FEDERAL RAILROAD ADMINISTRATION

OFFICE OF RAILROAD SAFETY 

VOLUME I - SIGNAL AND TRAIN CONTROL

COMPLIANCE PROGRAMS AND POLICIES

April 2012
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VOLUME I - TABLE OF CONTENTS

Chapter 1 – General ............................................................................................................. 1

Introduction ................................................................................................................................................ 1

Program Goals ............................................................................................................................................ 2

On-the-Job Training (OJT) Program .......................................................................................................... 2

S&TC Division Staff Director, HQ Staff Specialists, and HQ Staff Electronic Engineers ....................... 3

S&TC Division PTC Branch Supervisory Specialist (Branch Chief), PTC Senior Test Monitors, and 

PTC Regional Specialists ........................................................................................................................... 5

S&TC Regional Supervisory Specialist ..................................................................................................... 6

S&TC Railroad Safety Inspector ............................................................................................................... 8

Basis for Regulation and Inspection ........................................................................................................ 11

Signal and Train Control Regulations, Laws, and Orders ....................................................................... 12

Correct Reference to the Federal Regulations ......................................................................................... 13

Title 49 CFR Part 233 – Signal Systems Reporting Requirements – Overview ...................................... 14

Title 49 CFR Part 234 – Grade Crossing Signal System Safety and State Action Plans – Overview ..... 14

Title 49 CFR Part 235 – Instructions Governing Applications for Approval of a Discontinuance or 

Material Modification of a Signal System or Relief from the Requirements of Part 236 – Overview .... 15

Title 49 CFR Part 236 – Rules, Standards, and Instructions Governing the Installation, Inspection, 

Maintenance, and Repair of Signal and Train Control Systems, Devices, and Appliances – Overview . 16

Hours of Service Law Governing Railroad Signal Employees - Overview ............................................ 16

Personal Safety ......................................................................................................................................... 17

Chapter 2 – Inspection and Investigation Procedures .................................................... 18

Inventory of Inspection Territory (Regional Inspection Points) .............................................................. 18

Inspection Priorities ................................................................................................................................. 18

Discipline Inspection Guidance (DIG) .................................................................................................... 18

Using Data Analysis to Determine Appropriate Focus ............................................................................ 18

Preparation for Inspection or Investigation .............................................................................................. 24

Notice of Inspection or Investigation ....................................................................................................... 24

Time of Inspections and Investigations ................................................................................................... 25

Conference Prior to Inspection or Investigation ...................................................................................... 25

Followup Inspection or Re-inspection ..................................................................................................... 26

Refusal to Permit an Inspection or Investigation ..................................................................................... 26

Waiver of Responsibility ......................................................................................................................... 27

Unusual Problems or Incidents ................................................................................................................ 27

Cooperation of Personnel with Industry and other Governmental Agencies ........................................... 27

Chapter 3 – Gaining Compliance ..................................................................................... 28

Purpose ..................................................................................................................................................... 28

Regular Inspections .................................................................................................................................. 28

Conducting an Inspection or Investigation .............................................................................................. 29

Conference During and After an Inspection or Investigation .................................................................. 30

Special Inspections and/or Assessments .................................................................................................. 31

Special Investigations .............................................................................................................................. 33

Accident Investigation ............................................................................................................................. 33

Complaint Investigation ........................................................................................................................... 33

Block Signal or Waiver Application Investigation .................................................................................. 35
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False Proceed Signal Investigation .......................................................................................................... 35

Activation Failure Investigation ............................................................................................................... 37

Conducting Interviews ............................................................................................................................. 40

Determining When and What Enforcement Action Is Necessary ............................................................ 40

Handling of Defective Conditions ........................................................................................................... 42

Defective Conditions Not Cited as a Violation ........................................................................................ 42

Defective Conditions Cited as a Violation ............................................................................................... 42

Railroad Action to Correct Defective Conditions .................................................................................... 47

Written Reporting of Remedial Actions Taken ....................................................................................... 48

Chapter 4 – Field Reports, Procedures, and Forms ....................................................... 49

General Requirements .............................................................................................................................. 49

S&TC Inspections and Unit Count Guidelines ........................................................................................ 49

Completion of Inspection Report Form, FRA F6180.96 ......................................................................... 50

Distribution of Inspection Reports ........................................................................................................... 51

Regional Supervisory Specialist Review of Inspection Reports .............................................................. 51

Completion of Violation Report Form ..................................................................................................... 51

Distribution of Violation Reports ............................................................................................................ 52

Regional Supervisory Specialist Review of Violation Reports ............................................................... 53

Block Signal or Waiver Application Investigation Reports ..................................................................... 53

Regional Supervisory Specialist Review of Block Signal or Waiver Application Investigation Reports

 .................................................................................................................................................................. 53

False Proceed Signal Failure Investigation Reports ................................................................................ 54

Regional Supervisory Specialist Review of False Proceed Signal Failure Investigation Reports ........... 55

Highway-Rail Grade Crossing Activation Failure Investigation Reports ............................................... 55

Regional Supervisory Specialist Review of Highway-Rail Grade Crossing Activation Failure 

Investigation Reports ............................................................................................................................... 55

National Safety Program Plan (NSPP) Status Reports ............................................................................ 56

Other Special Project Reports .................................................................................................................. 56 

Activity Code Tables ........................................................................................ Appendix A

  
1 

Chapter 1 – General

Introduction 

This portion of the Signal and Train Control (S&TC) Technical Manual sets forth the methods, policies, 

and procedures that shall be used by Federal Railroad Administration (FRA) and State S&TC inspectors 

during their inspection and investigation activities to enforce and obtain railroad compliance with the 

regulations, laws, and orders issued by FRA, and such other activities as may be assigned as part of their 

duties. 

The directives and guidance contained in the S&TC Technical Manual are designed to maximize the 

effective use of available resources to obtain uniform application of FRA signal and train control 

regulations throughout the Nation. This uniformity is mandated, to the extent practicable, by the Federal 

Railroad Safety Act of 1970 and is necessary for the effective management of the national safety program. 

The S&TC Technical Manual is applicable to Federal and State S&TC inspectors and State highway-rail 

grade crossing inspectors. All S&TC personnel should refer to the manual as often as necessary to obtain 

a clear understanding of: (1) FRA policies, procedures, and programs, (2) proper applications of the 

regulations pertaining to signal and train control systems, and (3) required personal conduct while 

enforcing those regulations and performing inspections and investigations. If there is any doubt at any 

time about the intended meaning or proper application of any section of the manual, an inspector should 

ask his or her regional supervisory specialist for clarification. 

As Federal regulations continue to be revised, amended, and newly promulgated—or new FRA policies, 

procedures, or programs are created or existing ones revised—the manual will likewise be in need of 

revision. Therefore, any comments or suggestions pertaining to future revisions are encouraged. Such 

comments or suggestions should be forwarded to the S&TC Staff Director, through the respective 

regional supervisory specialist and/or Regional Administrator or Deputy Regional Administrator. 

The information in the manual is intended to provide internal guidance, and does not provide any basis for 

a private party to challenge FRA’s exercise of enforcement discretion in a particular case. The guidance 

provided in the manual may be revoked or modified by FRA without prior notice at any time. The 

manual supersedes all previous S&TC enforcement and/or compliance manuals. 

The manual is a complement to the Office of Railroad Safety’s General Manual (General Manual). The 

General Manual provides detailed information regarding FRA’s overall operation, history, and statutory 

authority; rulemaking process; and inspection and investigation procedures. Both manuals are 

specifically intended for use by S&TC safety inspectors and technical specialists throughout the country 

who monitor compliance with Federal law and safety regulations that apply to railroad signal and train 

control systems and highway-rail grade crossing warning devices. 

Using both the discipline-specific manual and the General Manual will aid FRA and State inspectors in 

the performance of their duties and in the uniform application of Federal S&TC safety laws and 

regulations. 
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Program Goals 

The goal of the S&TC safety program is to improve railroad safety by limiting the number of train 

accidents and highway-rail grade crossing accidents caused or contributed to by improperly installed 

and/or maintained signal and train control systems. This is done by reducing the number of unsafe 

failures and limiting the associated risks related to these systems. The S&TC safety program strives to 

reduce errors or defective conditions resulting in false proceed signal failures, malfunctions of highwayrail grade crossing active warning systems, noncompliance with the applicable Federal requirements, and 

other unsafe conditions related to signal and train control systems. FRA seeks to achieve the safety 

program’s goals through effective oversight of the level of compliance with the Federal requirements 

related to the design, installation, maintenance, inspection, testing, and repair of these systems. 

While FRA recognizes that it may never be possible for the railroads to eliminate all possibility of 

accidental derailments and/or collisions, FRA does believe it is possible to significantly reduce the 

number of rail-related accidents that do occur through compliance with its regulations. Very few 

accidents are actually caused by the failures of signal or train control systems. However, the record 

shows that each year the Nation’s railroads report dozens of false proceed signal failures and several 

hundred activation failures of highway-rail grade crossing active warning systems. One of FRA’s goals is 

to achieve a significant reduction of the occurrence of these type failures, thereby also reducing the risk of 

railroad accidents and injuries related to their occurrence. 

On-the-Job Training (OJT) Program 

The S&TC Field Training and Orientation Guide (also referred to as the OJT Booklet) is intended for OJT 

of new GS-09, -11, and -12 Federal inspectors as well as the State inspector equivalents of these grade 

levels. The standards contained in the guide are not intended to be used to evaluate GS-05 Federal 

inspectors or their State equivalents. However, they may be used for GS-07 inspectors, provided two 

conditions are met: (1) The GS-07 level trainee has completed the Level 2 task standards, and (2) FRA 

and the trainee have agreed upon a discipline of expertise for achieving the GS-09 level. 

The task inventories that provide the foundation of the OJT program are the consensus product of the 

Safety Improvement and Development Division (SIDD). The methodology used in development of the 

program included validation of the standards against the inspection program activity codes, as well as the 

policies and guidelines available in the enforcement manuals and technical bulletins. 

These standards supersede any previous methods the organization has used to evaluate proficiency levels 

of new inspectors. The use of written tests or other mechanisms to supplement the criteria set forth in this 

document are not acceptable, unless they are a formal part of the OJT program and listed in the OJT 

Booklet. 

The standards intentionally require a significant amount of practice; experience has proven that 

proficiency improves with repetition. 

The S&TC OJT program includes the following standards: 

 S&TC and State highway-rail grade crossing inspectors should not be partially certified for Title 

49 Code of Federal Regulations (CFR) Parts 233, 234, 235, or 236. 
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 All disciplines may be certified to perform Part 214 inspections once they have completed all 

related tasks, including completion of the self-study guide and test that are incorporated in those 

standards. 

Analysis of the table at the end of the foreword section of the OJT Booklet is critical for understanding 

the process. Those involved in the process should take particular note of the “Conditions” column, which 

places responsibility on the organization to provide the tools, equipment, documentation, and practice 

necessary for a new inspector to achieve the standards. 

The S&TC OJT standards are intended for two groups of inspectors: 

 

 Federal and State S&TC Inspectors 

 State Highway-Rail Grade Crossing Inspectors 

The tasks specific to Parts 233, 235, and 236 are for S&TC inspectors only. The tasks specific to 

Parts 214 and 234 are for both S&TC and State highway-rail grade crossing inspectors. For quick 

reference, the tasks that apply only to State highway-rail grade crossing inspectors are bolded and 

italicized in the table of contents of the OJT Booklet. 

S&TC regional supervisory specialists and inspectors should become familiar with the instructions and 

guidelines associated with the OJT program, and ensure that the standards are followed regarding all new 

S&TC inspectors. S&TC regional supervisory specialists and inspectors should read the foreword section 

of the OJT Booklet, specifically the section that outlines their roles and responsibilities. 

Additional OJT Booklets, computerized versions of the OJT Booklet, and the training verification forms 

can be obtained by contacting the S&TC training specialist. 

S&TC Division Staff Director, HQ Staff Specialists, and HQ Staff Electronic 

Engineers 

Responsibilities

The S&TC Division Staff Director is responsible for the technical oversight of all S&TC discipline 

functions and outcomes within the Nation, and for the highest level possible of uniform application and 

enforcement of all FRA regulations and orders pertaining to railroad signal and train control systems. He 

or she is a member of the staff of the Director–Office of Safety Assurance and Compliance, and serves as 

the ultimate technical advisor on all S&TC matters throughout the Nation. 

 

The FRA headquarters (HQ) staff specialists (staff specialists) and the HQ staff electronic engineers 

(electronic engineers), also referred to as HQ staff members, are responsible for the technical oversight of 

all S&TC discipline functions and outcomes within the Nation in the categories that are specifically 

assigned to them by the Staff Director. They are also responsible for providing the associated guidance 

necessary to achieve the highest level possible of uniform application of all Federal regulations and orders 

pertaining to railroad signal and train control systems. HQ staff members serve as the nationwide 

technical experts and advisors on specific S&TC matters as assigned by the Staff Director. 

 
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Duties

The Staff Director provides general technical review, evaluation, and analysis of the activities and 

outcomes of all inspection, enforcement, and investigation functions of the respective discipline. The 

Staff Director assigns and coordinates this oversight by specific category among the HQ staff members. 

The Staff Director and HQ staff members: 

 Provide guidance, direction, and advice to all personnel of the discipline in order to obtain the 

highest level possible of uniform application of the S&TC regulations. If there is a question about 

the correct application of a regulation, the regional supervisory specialist shall contact the Staff 

Director or the assigned HQ staff member for guidance. 

 Direct the implementation of national enforcement policies and programs and assist in determining 

railroad compliance with Federal railroad safety regulations, laws, and standards involving S&TC 

discipline matters. They maintain accident and signal-related failure information and evaluate the 

safety performance of railroads across the country. They identify the need and develop 

recommendations for railroad system assessments, special areas of focus, and adjustment of 

enforcement priorities that result from safety evaluations of S&TC discipline matters. 

 Direct the planning of special investigations and studies assigned throughout the Nation. For 

major investigations, the Staff Director and HQ staff members may personally plan and outline 

procedures to be followed and may be team leaders for a project. 

 Oversee the appropriate and successful development, testing, and implementation of new 

technologies within the S&TC discipline. This function, in great part, includes HQ staff 

involvement in the various Positive Train Control (PTC) projects ongoing nationwide. 

 

 Keep field personnel appropriately advised and involved to the extent available and applicable in 

these projects, and provide the guidance necessary in their development, implementation, and 

eventual in-service inspection techniques and practices. 

 Advise FRA senior leadership on railroad safety issues or concerns related to S&TC discipline 

matters having railroad system, regional, or national impact, and make suggestions or 

recommendations regarding revision of agency policies, procedures, and specific activities 

included in such as the National Safety Program Plan (NSPP) or the National Inspection Plan 

(NIP). 

 Represent FRA in contact with the railroad industry, other governmental agencies, unions, and 

civic and private groups related to all S&TC discipline matters. Through these contacts they are 

able to evaluate the status of assigned activities and ensure that the railroad industry and the public 

have a better understanding of FRA’s S&TC programs and functions. 
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S&TC Division PTC Branch Supervisory Specialist (Branch Chief), PTC Senior Test 

Monitors, and PTC Regional Specialists 

Responsibilities

The S&TC Division PTC Branch supervisory specialist (Branch Chief) provides specialized technical 

support to the Staff Director and S&TC Division, and leadership and direction to the other members of 

the PTC Branch staff. The Branch Chief also provides technical guidance to other internal and external 

personnel, related to PTC implementation and use across a major portion of the U.S. rail industry. He or 

she is a member of the staff of the Staff Director, and serves as the primary technical advisor to the Staff 

Director and other staff members on all PTC matters throughout the Nation. 

The PTC Branch senior test monitors and the PTC regional specialists are members of the staff of the 

PTC Branch Chief and are responsible for the direct oversight of the design and implementation of PTC 

systems, as assigned, that are occurring within the railroad industry. The PTC senior test monitors and 

PTC regional specialists provide advice and guidance within FRA and other agencies, and to industry 

signal engineering officials, manufacturers of signal equipment, and labor organizations on the 

requirements of the Rail Safety Improvement Act of 2008 (RSIA) and the Federal rules and regulations 

pertaining to PTC systems. 

Duties

The PTC Branch Chief leads and directs the PTC Branch staff in analyzing and overseeing the proper and 

safe development, testing, and implementation of PTC, as well as providing direction and guidance in 

monitoring the ongoing development, testing, and use of these systems. The PTC Branch Chief plans, 

develops, coordinates, implements, and directs the PTC Program consistent with the FRA NSPP and other 

policies and plans, the U.S. Department of Transportation (DOT) Strategic Plan, FRA technical directives 

and guidance, and accepted criteria for railway and structural engineering. He or she coordinates and 

directs the review of various industry-submitted PTC documentation, as well as the implementation of 

national enforcement policies and programs, to ensure a uniform enforcement of Federal laws, 

regulations, and standards pertaining to PTC systems. The PTC Branch Chief serves as the primary 

advisor to the Staff Director on all aspects of PTC development, testing, and program implementation, to 

include development and revision of national policies, programs, rules, regulations, standards, and 

procedures related to the program. 

The PTC Branch Chief, senior test monitors, and PTC regional specialists: 

 Provide oversight of the design and implementation of PTC systems that are occurring within the 

railroad industry. 

 Review PTC systems and all associated documentation submissions as they are developed and 

provide recommendations to the Staff Director, the PTC Branch Chief, and the senior technical 

staff of the Associate Administrator for Railroad Safety/Chief Safety Officer. 

 Provide advice and guidance within FRA, other agencies, industry signal engineering officials, 

manufacturers of signal equipment, and labor organizations on the requirements of Federal rules 

and regulations in this area of expertise. 
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 Attend various review and planning meetings associated with the individual PTC projects. 

 Monitor laboratory and field testing of PTC systems presently under development and test, as well 

as future systems, to ensure the proper and safe development, testing, and implementation of PTC 

within the U.S. 

 Determine railroad compliance with Federal railroad safety regulations, laws, and standards 

involving PTC matters. 

 

 Provide technical advice to the railroads and help ensure that the applicable Federal regulations are 

adhered to and that safety principles are appropriately applied to these projects and programs. 

 Provide advice to FRA regional personnel on PTC systems and the application of the associated 

rules. 

 Conduct evaluations of PTC system failures and focused inspections of PTC systems. 

 Assist the S&TC Training Specialist in developing training materials related to PTC systems and 

in training classes as needed. 

S&TC Regional Supervisory Specialist 

Responsibilities

The S&TC regional supervisory specialist (regional specialist) is responsible for the technical review and 

oversight of all S&TC inspection and investigation activity within his or her region, and for the uniform 

application and enforcement of all FRA regulations and orders pertaining to railroad signal and train 

control systems. The regional specialist is a member of the staff of the Regional Administrator and serves 

as the primary advisor on all S&TC matters within his or her region. 

Duties 

The regional specialist reports to and receives direction from the Regional Administrator. On matters 

pertaining to signal and train control systems, the regional specialist serves as a staff advisor to the 

Regional Administrator. 

In addition, the regional specialist has the following duties: 

 Provides technical evaluation of the S&TC safety inspectors (S&TC inspectors) and their work. 

The regional specialist will also coordinate the assignment and review of special assignments 

involving S&TC inspectors while exercising administrative supervision over a dispersed technical 

workforce. Approves work schedules and forms of leave, counsels employees, adjudicates 

employee complaints and problems, evaluates performance of subordinates, identifies and makes 

provisions for training needs of employees, and interviews candidates and makes 

recommendations for appointments, promotions, and reassignments. 
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 Provides guidance and advice to the S&TC inspectors in his or her region in order to attain 

uniform application and enforcement of the S&TC regulations. If there is a question about the 

correct application of a regulation, the regional specialist shall contact the S&TC Staff Director or 

S&TC HQ staff specialists for their guidance. 

 Provides the assignment and evaluation of individual inspection areas to attain a uniform and 

effective workload among the various S&TC inspectors in his or her region. 

 Reviews S&TC inspection reports; technical correspondence; and reports of investigations of false 

proceed signal failures, highway-rail grade crossing activation failures, applications and waivers, 

complaints, violations, etc., for timeliness, appropriate format, as well as technical thoroughness 

and correctness. Assures that associated reports are complete, accurate, meet expected standards, 

and are submitted in an appropriate and timely manner. 

 Provides coordination of the investigation and preparation of the reports of investigations of 

serious rail accidents, and reviews the final report for technical thoroughness and accuracy of 

items pertaining to signal and train control systems. 

 Assigns the investigation of railroad applications to remove or materially modify signal or train 

control systems, and for relief from the requirements of signal-associated Federal regulations. 

Further, the regional specialist provides the review for completeness and technical accuracy of the 

resulting report before it is forwarded through the Regional Administrator to the Associate 

Administrator for Railroad Safety/Chief Safety Officer. 

 Directs the implementation of regional enforcement policies and programs to determine railroad 

compliance with Federal safety regulations, laws, and standards pertaining to railroad safety 

involving signal and train control matters. Maintains accident and signal failure information and 

evaluates the safety performance of railroads in his or her area of responsibility. Identifies the 

need and develops recommendations for system assessments and adjustments of enforcement 

priorities that result from his or her safety evaluation of signal and train control matters. 

 

 Directs the formulation of plans for special investigations and studies assigned within the region. 

For major investigations, the supervisory specialist may personally plan and outline procedures to 

be followed. Reviews planned and completed itineraries to ensure thorough coverage of 

inspection points and economy of travel. Directs the investigation of violations and complaints 

regarding railroad safety, or alleged noncompliance with safety rules. 

 

 Provides input and recommendations for the revision of existing regulations and promulgation of 

new regulations involving signal or train control systems. 

 Provides guidance to State S&TC or highway-rail grade crossing inspectors and monitors their 

activities to achieve inspection efforts that are uniform with FRA’s goals and activities. 

 Carries out such special inspections, investigations, or other projects as may be assigned to him or 

her. 
8 

 Develops plans of action to resolve unique problems involving signal or train control systems and 

the compliance with associated regulations and standards that might come to his or her attention. 

 Maintains appropriate and effective contact with the railroads that operate in his or her region and 

with manufacturers of signal equipment to keep abreast of new installations on the railroads, and 

new industry developments in the design of signal and train control systems. 

 Administers the responsibilities of the Regional Administrator in his or her absence (when 

directed). 

S&TC Railroad Safety Inspector 

Responsibilities

The S&TC railroad safety inspector (S&TC inspector) is responsible for the enforcement of all Federal 

rules, regulations, and orders pertaining to railroad signal and train control systems within an assigned 

inspection area. The S&TC inspector is obligated to perform inspections and investigations within the 

guidelines established by FRA and effectively enforce the appropriate regulations, orders, or statutes. If 

the S&TC inspector is unsure about the application or relevancy of a particular regulation, it is the 

responsibility of the S&TC inspector to consult with his or her regional specialist for a correct application. 

In instances where the regional specialist is unavailable and guidance is needed immediately, the S&TC 

inspector may consult with the Staff Director or the HQ staff specialist assigned to the specified area or 

topic of interest. In such a case, the regional specialist shall be readily advised of the results of the 

consultation. 

DOT and FRA require that S&TC inspectors perform their duties with courteous and professional 

deportment. S&TC inspectors are representatives and the primary public contacts of the agency. It is the 

S&TC inspector’s responsibility to see that his or her activities and demeanor reflect creditably on the 

FRA. FRA’s success in obtaining railroad compliance with its railroad safety program depends not only 

on S&TC inspectors being fully knowledgeable and consistent in correctly applying the railroad safety 

regulations, orders, and statutes, but also on S&TC inspectors acting in a polite and professional manner. 

S&TC inspectors must never engage in conduct or make statements that are unbecoming to their 

positions, even if such conduct or statements are invited or provoked by the people with whom they are 

dealing. S&TC inspectors shall not make any derogatory remarks about any railroad, railroad employee, 

or group of railroad employees. Likewise, S&TC inspectors shall not make any derogatory remarks or 

recommendations about any manufacturer, manufacturer’s employees, or a manufacturer’s product, nor 

about any service a railroad contractor might offer. 

It is the responsibility of the S&TC inspector to be aware of and to conform to the rules of conduct in 

order to eliminate the possibility of being accused of actually having (or having the appearance of) a 

conflict of interest. No S&TC inspector shall (or appear to) solicit, accept, or agree to accept—directly or 

indirectly—any favor, gift, loan, free service, or other item of economic value in any form whatsoever, 

from any railroad or railroad employee, or from any outside person, corporation, or group, if the S&TC 

inspector has reason to believe that the person, corporation, or group: 
9 

1. Has, or is seeking to obtain, contractual or other business of a financial relationship with DOT or a 

State agency; 

2. Conducts operations or activities that are regulated by DOT; 

3. Has interests that may be substantially affected by the S&TC inspector’s performance or 

nonperformance of his or her official duties; or 

4. Is attempting to reward or influence the S&TC inspector’s official actions. 

It is the responsibility of the S&TC inspectors to be guarded in their conversations in public places and to 

refrain from discussing the affairs of FRA or from making critical comments about the policies, actions, 

or competence of officials or employees of FRA or any other governmental, railroad, or labor 

organization. 

S&TC inspectors shall remain aware that the railroads are private corporations and the conduct of their 

business is the prerogative of their officers. S&TC inspectors shall not preempt the authority of railroad 

officials to issue lawful orders or instructions to railroad employees. 

 

S&TC inspectors are frequently asked about the applicability or the proper technical application of FRA’s 

signal or train control regulations. It is the responsibility of the S&TC inspector to give appropriate 

answers regarding the application of the Federal regulations by making reference to the proper regulations 

and appropriate documents. If S&TC inspectors have any reservations about a particular issue, they shall 

refer the question to their regional specialist. 

From time to time, S&TC inspectors will be asked about Federal regulations other than railroad S&TC 

regulations. S&TC inspectors shall not attempt to furnish answers about Federal regulations governing 

other disciplines, but shall refer such questions to the regional office for resolution. Further, S&TC 

inspectors shall not respond to inquiries concerning regulations not promulgated by FRA, but shall, in a 

courteous manner, suggest to the persons making such inquiries that they contact the agency or 

administration having jurisdiction in such matters. 

In addition to the issues addressed above, State inspectors should be familiar with and adhere to the rules 

of conduct prescribed by their respective States. 

Duties

The S&TC inspector shall: 

 Carry out the FRA compliance program and conduct such investigations that may be assigned to 

him or her in compliance with established procedures. An S&TC inspector shall not undertake the 

investigation of matters not within FRA’s purview without the express authority of his or her 

supervisor. 

 Inspect and observe testing of railroad signal and train control systems, devices, appliances, and 

similar systems for compliance with the Rules, Standards, and Instructions (RS&I), and the Grade 

Crossing Signal System Safety and State Action Plans requirements. At the conclusion of each 
10 

inspection, an S&TC inspector shall issue an inspection report (Form FRA F 6180.96) to a railroad 

representative accompanying the inspector or otherwise having jurisdiction, citing the defects 

found and, if appropriate, recommending that a violation report be forwarded to FRA’s Office of 

Chief Counsel. 

 Monitor railroad properties to ensure that railroads are in compliance with all applicable CFR 

parts, including the requirements for reporting, the requirements and provisions for the filing of 

block signal applications, and the process for applying for relief from the RS&I and/or the Grade 

Crossing Signal System Safety and State Action Plans requirements, respectively. 

 Conduct investigations of railroad accidents as directed by his or her supervisor, or (as occasion 

demands) on his or her own initiative. He or she shall make inspections and observe railroad tests 

to determine the condition and operation of the involved signal and train control systems and 

devices, or the highway-rail grade crossing active warning systems and devices, in service at the 

time of the accident. The investigation of the accident should include an evaluation of each of the 

following: 

o The railroad’s associated operating practices and operating rules 

o The condition and design of the railroad’s associated signal system 

o The stopping distances of trains involved 

o The appropriate spacing of associated signals for the train speeds involved 

o Any other significant factors contributing to the accident. 

The S&TC inspector shall submit a detailed report of his or her investigation and file appropriate 

violation reports where warranted. 

 Conduct investigations of complaints alleging noncompliance with FRA’s signal regulations or of 

malfunctioning signal and train control systems, devices, or appliances, or any other unsafe 

conditions, when assigned to do so by his or her supervisor. When the investigation is completed, 

an S&TC inspector shall submit a written report of the investigation. This report shall clearly state 

whether the allegations were substantiated and what action was taken. If the S&TC inspector 

finds that the allegations are substantiated and involve noncompliance with any FRA regulation, 

he or she shall file a violation report, when warranted. 

 Conduct investigations and submit reports with his or her recommendations for action to be taken 

on railroad applications to discontinue or materially modify signal and train control systems, or on 

petitions for relief from applicable Federal requirements, when assigned to do so by his or her 

supervisor. 

 Conduct investigations and submit reports of investigations of reported false proceed signal 

failures, highway-rail grade crossing activation failures, and other related reports when instructed 

to do so by his or her supervisor. If an S&TC inspector learns of a condition that appears to 

present imminent danger to the passage of trains, to the safety of railroad employees, or to the 

general public, he or she is expected to take immediate action to ascertain the facts and then take 

such action, as appropriate, to prevent an accident or incident. The S&TC inspector will inform 

his or her supervisor or other regional management of the events and of his or her actions as soon 

as possible. 
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 Maintain an appropriate and effective liaison with the railroad officers in his or her inspection area 

and with industry representatives to keep abreast of new signaling technologies and new 

developments in railroad signal equipment. 

 Assist as assigned in the training of State S&TC inspectors where such State inspectors are 

employed. 

Basis for Regulation and Inspection 

Statutory Authority

FRA’s authority to promulgate and enforce regulations pertaining to railroad signal systems derives from 

the Federal Railroad Safety Statutes (49 U.S.C. ch. 201-213), which have incorporated the Signal 

Inspection Act of 1937 (Signal Inspection Act) and the Federal Railroad Safety Act of 1970 (Federal 

Railroad Safety Act). The Signal Inspection Act and the Federal Railroad Safety Act, as amended, give 

the Secretary of Transportation virtual plenary authority over signal and train control systems in use on 

the Nation’s railroads. As discussed below, the legislation gives the Secretary authority to (1) order 

railroads to install signal and train control systems, devices, and appliances; (2) prohibit railroads, 

without approval, from materially modifying or discontinuing signal and train control systems once 

installed; (3) promulgate regulations pertaining to the installation, maintenance, and repair of signal and 

train control systems; (4) order the railroads to report failures of signaling devices in such manner as the 

Secretary may require; (5) prohibit the railroads to use or permit to be used any system, device, or 

appliance that is not in condition to be safely used; and (6) inspect and observe testing of the signal and 

train control systems in use on the Nation’s railroads. 

The Signal Inspection Act sets forth the basic requirements pertaining to railroad signal systems. When it 

was enacted by Congress on August 27, 1937, the statute charged the Interstate Commerce Commission 

(ICC) with the responsibility for administering the provisions of the act. Pursuant to the Department of 

Transportation Act of 1966, that responsibility now rests with the Secretary of Transportation and has 

been delegated to FRA. 

The Signal Inspection Act provides that the Secretary may—after an investigation and if found to be in 

the public interest—order any railroad, within a time specified in the order, to install a block signal 

system, interlocking, automatic train stop, train control, and/or cab signal devices, and/or other similar 

appliances, methods, and systems intended to promote the safety of railroad operation (collectively 

referred to as “signal systems”). The railroad operation would be required to comply with the 

requirements prescribed by the Secretary, upon the whole or any part of its railroad, as prescribed in the 

order. Further, the Signal Inspection Act provides that any such signal systems put into service or 

installed pursuant to an order of the Secretary may not be discontinued or materially modified without the 

consent of the Secretary. 

The Signal Inspection Act authorizes the Secretary to promulgate rules, standards, and instructions for the 

installation, inspection, maintenance, and repair of systems, devices, and appliances covered by the Act; 

serve them on the railroads, and make them obligatory for each railroad. 
12 

The Signal Inspection Act further provides that each railroad shall be required to report to the Secretary, 

in such manner as the Secretary might determine, each signal system failure to function as intended. In 

cases where an accident that is caused by the failure of a signal system results in an injury to person or 

property, the railroad is required to make a written report of the failure and circumstances of the accident. 

Such accidents also are subject to investigation by the Secretary. 

Authority to Inspect

Under the Signal Inspection Act, it is unlawful for a railroad to use any signal system covered by S&TC 

regulations unless the signal system can be operated without unnecessary peril to life and limb. The 

signal system must be inspected from time to time and meet the requirements of those tests required by 

the rules, standards, and instructions adopted and approved by the Secretary. FRA’s S&TC employees 

play an essential role in ensuring that such signal systems are properly inspected and that they operate 

safely. 

The Federal Railroad Safety Act generally provides authority for the Secretary to “enter and inspect 

railroad equipment, facilities, rolling stock, operations, and relevant records.” The Signal Inspection Act 

specifically authorizes the Secretary to inspect and observe testing of S&TC systems to determine that the 

systems are in proper condition to operate and provide adequate safety. The Secretary may employ 

persons familiar with signal systems to make inspections. However, such persons may not have an 

interest in a patented article that is required to be used in a railroad signal system and cannot have a 

financial interest in a railroad carrier or in an entity that deals in railroad supplies. 

Penalties for Violations of S&TC Regulations 

The Federal Railroad Safety Act, as amended, set penalties for violations of FRA regulations governing 

railroad signal systems, railroad employees engaged in signal construction and maintenance work under 

the hours of service laws, and provided further authority for safety regulations. Through subsequent 

legislation, the penalty amount for a violation of an FRA regulation pertaining to signal systems can range 

from $650 to $100,000. 

Signal and Train Control Regulations, Laws, and Orders 

The Interstate Commerce Commission (ICC) issued the initial rules pertaining to signal and train control 

systems on September 24, 1937. Under the new rules, railroads could no longer discontinue or materially 

modify signal or train control systems without approval of the ICC. Each railroad was required to file its 

rules, standards, and instructions for such systems within 6 months after the enactment of the amendatory 

provisions. Moreover, those railroads owning signal or train control systems were required to 

immediately report each accident resulting from the failure of such systems, devices, or appliances to 

function as intended. 

On December 1, 1937, the ICC issued detailed instructions on the procedure for submitting applications 

for approval of a discontinuance or material modification, and for the reporting of signal failures and 

accidents on published forms beginning with the month of January 1938. In response to the failure of 

most railroads to submit their own rules, standards, and instructions for railroad signal systems, the ICC in 

1939 issued its own Rules, Standards, and Instructions for the Installation, Inspection, Maintenance, and 

Repair of Automatic Block Signal Systems, Interlocking, Centralized Traffic Control Systems, Automatic 
13 

Train Stop and Train Control Systems, Automatic Cab Signal Systems, Dragging Equipment and Slide 

Detectors and other Similar Protective Devices, and Other Similar Appliances, Methods, and Systems (the 

RS&I). The RS&I was originally promulgated under 49 CFR Part 136. On April 1, 1967, the RS&I was 

retitled as 49 CFR Part 236 as a result of the creation of FRA under DOT. 

On June 17, 1947, the ICC issued Order 29543, which required the Nation’s railroads to install a manual 

block system or an automatic block signal system on any track where freight trains were permitted to 

operate at 50 or more mph or passenger trains were permitted to operate at 60 mph or more. Order 29543 

also required an automatic cab signal system, automatic train stop system, or automatic train control 

system be installed on any track where any train would be permitted to operate at 80 mph or more. 

Further, such systems were required to comply with the RS&I, identified then as 49 CFR Part 136. Many 

efforts were made to modify Order 29543 over the years, but the Order remained unchanged until 

February 27, 1984, when its provisions were modified and incorporated into the FRA’s Rules RS&I, now 

49 CFR Part 236. 

Presently, there are four parts of 49 CFR that pertain exclusively to railroad signal and train control 

systems: Parts 233 (Signal Systems Reporting Requirements), 234 (Grade Crossing Signal System Safety 

and State Action Plans), 235 (Instructions Governing Applications for Approval of a Discontinuance or 

Material Modification of a Signal System or Relief from the Requirements of Part 236), and 236 (Rules, 

Standards, and Instructions Governing the Installation, Inspection, Maintenance, and Repair of Signal and 

Train Control Systems, Devices, and Appliances). Federal and State S&TC inspectors also affect 

oversight of compliance with requirements for Roadway Worker Protection, Bridge Worker Safety, and 

Roadway Maintenance Machines found in Part 214, and of the limitations and requirements of the Hours 

of Service Act related to Signal Covered Service as well as the associated recordkeeping and reporting 

requirements of Part 228. 

Correct Reference to the Federal Regulations 

Many times Federal and/or State personnel must reference Federal regulations, verbally and/or in written 

form. It is important that the manner in which those references are made be technically proper. The 

following guidance is provided so that reference can be made in the technically correct manner. 

The applicable regulations are found in 49 CFR–Transportation, Parts 200–299 under the title Chapter II– 

Federal Railroad Administration, Department of Transportation. CFR parts may be divided into subparts. 

Each rule within a part or subpart is titled as a “section” (symbol §). A section may be divided into 

subsections. A few examples of correct reference are as follows: 

 Title 49 CFR Part 233, Section 5, or directly referred to as Section 233.5 or § 233.5; 

 Title 49 CFR Part 234, Subpart D, Section 209, subsection (b)(1), or directly referred to as 

Section 234.209(b)(1) or § 234.209(b)(1); 

 Title 49 CFR Part 235, Section 7, Subsection (b)(24)(vi), or directly referred to as 

Section 235.7(b)(24)(vi) or § 235.7(b)(24)(vi); 

 

 
14 

 Title 49 CFR Part 236, Subpart E, Section 587, Subsection (a)(4), or directly referred to as 

 Section 236.587(a)(4) or § 236.587(a)(4). 

Notice that there is a space between the section symbol (§) and the number, just like if section were 

spelled out, but no spaces between the section number and the subsection(s) (i.e., § 235.7(c)(24)(vi)). 

Title 49 CFR Part 233 – Signal Systems Reporting Requirements – Overview 

Title 49 CFR Part 233, “Signal Systems Reporting Requirements,” contains the reporting requirements 

and sets forth the responsibilities of the railroads to report to FRA, in a timely manner, the occurrence of 

the failure of an appliance, device, method, or system to function or indicate as required by Part 236 that 

results in a more favorable aspect than intended or other condition hazardous to the movement of a train 

(commonly termed false proceed signal failures), and specifically the occurrence of any accident/incident 

caused by signal failures. It also requires railroads to report, once every 5 years, current information 

surrounding their methods of operation, block signal systems, interlockings, traffic control systems, 

automatic train stop, train control, and cab signal systems, or other similar appliances, methods, and 

systems. 

Part 233 requires the railroads to report any failure of a signal system or its components to function or 

indicate as intended within 15 days of the occurrence and requires the railroad to report within 24 hours 

by telephone, any accident/incident that is caused by a failure of a signal system or a component of a 

signal system to function as intended. A toll-free telephone number is maintained by FRA for such 

reporting. The 5-year signal systems report initially became due no later than April 1, 1997, and once 

every 5 years thereafter. This report is used by FRA to compile statistics on how our Nation‘s railroads 

are being operated. 

The technical application of Part 233 regulations is further defined in Volume II of FRA’s Signal and 

Train Control Technical Manual titled: “S&TC Regulations, Technical Applications, and Defect Codes.” 

The manual section addressing Part 233 provides authoritative guidance regarding the correct application 

of the Federal requirements, as well as a listing of the appropriate defined defect codes, regarding the 

reporting requirements of Part 233. 

Title 49 CFR Part 234 – Grade Crossing Signal System Safety and State Action Plans 

– Overview 

Title 49 CFR Part 234, “Grade Crossing Signal System Safety And State Action Plans,” contains the 

reporting requirements and sets forth the responsibilities of railroads regarding the installation, 

maintenance, inspection, testing, and repair of highway-rail grade crossing active warning systems, 

devices, and appliances; as well as recordkeeping, and activation failure and accidents caused by 

activation failure, reporting requirements. 

The technical application of the Part 234 regulations are further defined in Volume II of FRA’s Signal and 

Train Control Technical Manual titled: “S&TC Regulations, Technical Applications, and Defect Codes.” 

The chapter addressing Part 234 provides authoritative guidance regarding the correct application of the 

Federal requirements, as well as a listing of the appropriate defined defect codes, regarding the inspection 

and determination of compliance related to highway-rail grade crossing active warning systems, devices, 

and appliances. 
15 

The rules contained in Part 234 are used by inspectors in their inspection and investigation activities, and 

are the minimum standards by which highway-rail grade crossing warning systems are evaluated for 

compliance. It is pertinent to note that many railroads have adopted their own standards that are more 

stringent than those set forth in Part 234. However, the FRA and State inspectors can enforce only the 

minimum standards set forth in Title 49 CFR Part 234. 

Title 49 CFR Part 235 – Instructions Governing Applications for Approval of a 

Discontinuance or Material Modification of a Signal System or Relief from the 

Requirements of Part 236 – Overview 

Title 49 CFR Part 235, “Instructions Governing Applications for Approval of a Discontinuance or 

Material Modification of a Signal System or Relief from the Requirements of Part 236,” prescribes the 

procedure to be used by a railroad to obtain FRA approval of a discontinuance or material modification of 

a signal or train control system or similar protective system or device. As noted above, these instructions 

were originally issued by the ICC in 1937. They have been amended many times to help ensure that 

discontinuation, modification, and regulatory relief issues are clearly defined. The railroads may examine 

these rules to determine the circumstances under which an application must be filed. 

Part 235 also provides the format for such applications, and details the information the railroad must 

provide with its application. Part 235 further sets forth the procedure and details regarding the manner in 

which an application is to be filed in order to gain relief from any provision of Part 236, the RS&I. Such 

applications are acted on by FRA and relief is either granted, dismissed, or denied. In the matter of both 

block signal applications and applications for regulatory relief, FRA may take one of the following 

actions: 

 Approve the application 

 Approve the application with conditions 

 Approve the application in part and deny the application in part 

 Dismiss the application as either not being necessary or not being filed in accordance with the 

requirements 

 Deny approval of the application in the interest of safety. 

The railroad may petition FRA for reconsideration, and the agency may reconsider the application if the 

conditions and information warrant such an action. 

Further, FRA may hold public hearings to permit a railroad to make its case and/or to permit interested 

parties and the general public to present arguments and information that might have a bearing on the case. 

A notice of such hearings will be published in the Federal Register, and such hearings are normally held 

at or near the application area to permit easier access by those most interested in the disposition of the 

application. 

The technical application of the Part 235 regulations is further defined in Volume II of FRA’s Signal and 

Train Control Technical Manual. The chapter addressing Part 235 provides authoritative guidance 

regarding the correct application of the Federal requirements, as well as a listing of the appropriate 
16 

defined defect codes regarding the filing of block signal applications and requests for relief from the 

requirements of Part 236. 

Title 49 CFR Part 236 – Rules, Standards, and Instructions Governing the 

Installation, Inspection, Maintenance, and Repair of Signal and Train Control 

Systems, Devices, and Appliances – Overview 

Title 49 CFR Part 236, “Rules, Standards, and Instructions Governing the Installation, Inspection, 

Maintenance, and Repair of Signal and Train Control Systems, Devices, and Appliances,”—referred to as 

the Rules, Standards, and Instructions (RS&I)—governs the installation, maintenance, inspection, and 

testing of signal and train control systems on our Nation’s railroads. 

The RS&I have been modified many times since its adoption in 1939. Major revisions were made to the 

RS&I on January 26, 1984, which became effective on February 27, 1984. Additional major revisions 

were made on March 7, 2005, becoming effective on June 6, 2005, when Part 236, Subpart H (the 

“processor-based” rule commonly known as the PTC rule) became a final rule. The most recent major 

revisions were made on January 15, 2010, becoming effective on March 16, 2010, when Subpart I (the 

mandate for PTC subsequent to the RSIA) became a final rule. 

Part 236 now contains the provisions of the original Order 29543 as well as all the regulations pertaining 

to the installation, maintenance, inspection, testing, and repair of signal and train control systems, 

protective devices or systems, and other similar devices, systems, and methods. The RS&I are the 

technical regulations governing the way signal and train control systems are to be designed, installed, 

tested, and maintained. 

The technical application of the Part 236 regulations is further defined in Volume II of FRA’s Signal and 

Train Control Technical Manual. The chapter addressing Part 236 provides authoritative guidance 

regarding the correct application of the Federal requirements, and lists the appropriate defined defect 

codes regarding the installation, maintenance, inspection, testing, and repair of signal and train control 

systems, devices, and appliances. 

The rules contained in Part 236 are used by inspectors in their inspection and investigation activities, and 

are the minimum standards by which a railroad’s signal and train control systems are evaluated for 

compliance. It is pertinent to note that many railroads have adopted their own standards that are more 

stringent than those set forth in Part 236. However, FRA and State S&TC inspectors can enforce only the 

minimum standards set forth in title 49 CFR Part 236. 

Hours of Service Law Governing Railroad Signal Employees - Overview 

The Hours of Service Act (“Act”) was first enacted in 1907, and was intended to promote the safety of 

employees and travelers upon railroads by limiting the hours of service of certain railroad employees. 

The original Act, popularly known as “the 16-hour law,” covered only certain operating employees and 

employees engaged in the transmittal or receipt of train orders. The Act has been amended several times, 

with major changes being made in 1969, 1976, and 2008. First enacted into law in 1976, the limitations 

on hours of signal employees were clarified by the 1978 amendments. 
17 

FRA S&TC inspectors assigned to perform hours of service inspections or investigations should consult 

FRA Technical Bulletin G-00-02, “The Federal Hours of Service Laws and Signal Service.” The 

guidance in this technical bulletin, along with that which may be attained from either the FRA S&TC 

Division or the Operating Practices Division at HQ, provides the guidance necessary for inspection and 

investigation related to railroad signal employees’ hours of service. This technical bulletin is in the 

process of being updated to reflect FRA’s final decisions regarding the correct interpretation of the most 

recent modifications to both the law and the recordkeeping and reporting requirements. Once completed, 

this manual will be revised accordingly with the reissued technical bulletin. 

The technical application of the hours of service requirements are further defined in Volume II of FRA’s 

Signal and Train Control Technical Manual. The chapter addressing hours of service–Rules of Signal 

Service, along with the recordkeeping and reporting requirements of Part 228, provides authoritative 

guidance regarding the correct application of the Federal requirements, regarding the limitations and 

associated recordkeeping and reporting requirements of the hours of service related to signal employees. 

Personal Safety 

Inspectors shall make a conscious effort to maintain their personal safety and the safety of those with 

whom they are working. Inspectors should watch for and voice a cautionary warning if they see any 

condition that might imperil any person comprising the inspection group, or any train movement. 

Inspectors should be especially alert and attentive when riding on the rails in hi-rail vehicles. The safety 

of everyone in the vehicle makes it imperative that each person aboard understands the rules and authority 

limitations under which they operate. Each person must be aware that their subsequent actions and 

vehicle movements must comply with those rules and authorities. Be particularly wary when inspections 

and/or investigations are being performed on or around multiple track main lines, and/or third-rail 

electrified territory. 

The inspector shall strive in every way possible to comply with the provisions of the Roadway Worker 

Protection regulations found at 49 CFR Part 214. Failure to comply with these regulations sends the 

wrong message to railroad employees who may observe this action. 

If the inspectors have their own safety equipment, they shall use it. If the railroad provides other 

additional safety equipment and requests that it be used, inspectors shall comply with the railroad’s 

request. 
18 

Chapter 2 – Inspection and Investigation Procedures

Inventory of Inspection Territory (Regional Inspection Points) 

Each inspector will use the inventory of signaling devices located within his or her inspection area to 

assist in the planning of inspection activity. Inspectors shall keep their Regional Inspection Points (RIP) 

inventory updated by noting the changes in signaling apparatus or systems while making their inspections. 

When requested, inspectors will provide the regional supervisory specialist with updated information to 

maintain a reliable inventory of signaling systems, devices, and appliances. 

Inspection Priorities 

The Regional Administrator, through the regional supervisory specialist, shall establish priorities 

appropriate to the urgency and seriousness of any alleged violation or other situation. If catastrophic 

and/or fatal accidents, or complaints of a serious nature, require the full usage of existing resources, the 

regional supervisory specialist shall accomplish the handling of the problems before releasing resources to 

resume the activity of regular inspection work. 

Unless otherwise instructed, an inspector shall perform his or her duties in accordance with definite 

priorities. The priorities established are as follows: 

Priority Category

 1 Accident Investigation 

 2 Complaint Investigation 

 3 BSAP/Waiver Application Investigation 

 4 False Proceed Signal Failure/Activation Failure Investigation 

 5 Assessments/Special Inspection 

 6 Regular Inspection 

Discipline Inspection Guidance (DIG) 

The following guidance was developed so that those working in the S&TC discipline may best determine 

the areas on which to focus the attentions of their limited resources. This guidance is intended to work in 

harmony with the allocation of resources identified in the NIP resource allocation model provided 

annually to each region, which the Regional Administrator may adjust as the need arises. This guidance 

may be revised as database programs, or other applicable information or processes, change. 

Using Data Analysis to Determine Appropriate Focus 

Purpose:

The purpose of using data analysis to determine appropriate areas of focus in ongoing S&TC 

inspection/investigative efforts is so that we can best determine how to use FRA’s limited resources 

toward areas of identified concern, and therefore increase rail safety. Analysis of the data most applicable 

includes: signal-caused rail equipment accidents/ incidents, malfunction-related highway-rail grade 
19 

crossing accident/incidents, false proceed signal failures, highway-rail grade crossing active warning 

system activation failures, and past inspection efforts and findings. Other possible areas of consideration 

may become available on a case-by-case basis (e.g., high-profile accidents/incidents, complaints, waivers, 

etc.). Pertinent data related to these primary areas indicated above needs to be tracked, sorted, and 

analyzed on a national level, on specific railroads, within each specific region, and/or within each specific 

inspector’s assigned territories. 

The most uniformly accurate, thorough, and cost- and time-effective way to sort and analyze a major part 

of this data currently is through the detailed data programs developed by FRA’s Knowledge Management 

staff. The exception will be the direct review and analysis, by HQ and the regions, of both the false 

proceed signal and activation failure databases. What follows is a description of the data retrieval, 

review, and analysis process within each category, including who should perform what function and how 

often, and how the findings should be determined, formatted, and disseminated. 

1. Rail Equipment Accidents/Incidents:

The review of rail equipment accidents/incidents is performed in order to identify any that involved signal 

causes and sort them by cause, problem area, and any trends that warrant particular follow up or attention. 

While there are relatively few train accidents associated with signal causes, the S&TC discipline still 

needs to be informed when they occur. We further need to identify and separate those events that are 

truly “signal caused” in the sense of discipline-related technical or regulatory issues within a signal or 

train control system (e.g., false proceed signal failure) as opposed to those that are of a different nature 

(e.g., accidents involving yard, hump, or retarder operations, radio communication, hand signals, etc.). 

Both categories are important, but they may warrant different types of responses and follow up by FRA. 

Railroads are required to file a Rail Equipment Accident/Incident Report (Form 6180.54) to report rail 

equipment accident/incidents to FRA within 30 days following the end of the month in which the event 

occurred. (See 49 CFR §§ 225.11 and 225.19) However, this is not the only reporting requirement when 

an accident/incident involves a signal system failure. Railroads are required to report to FRA any 

accident/incident arising from a signal failure within 24 hours of the event, through the National Response 

Center (NRC), by toll-free telephone. See 49 CFR § 233.5. Therefore, FRA should have very timely 

knowledge of the occurrence of these types of events. The S&TC HQ staff will review accident/incident 

reports being submitted by railroads for those that indicate a signal cause, determine if any necessary 

telephonic notification was forthcoming, and review for incomplete or incorrect reporting (particularly 

related to cause). Discrepancies in these reporting areas will be handled for correction with the reporting 

railroad. 

The data to be retrieved should include the numbers and specifics associated with the previous full 

calendar year and the current year-to-date information. This data should be sorted monthly on a national 

perspective by railroad, region, and cause. 

A HQ staff member will use the Office of Safety Analysis Web site to retrieve all train accident data 

associated with signal causes (see criteria below). Any accident/incident indicating a signal cause will be 

listed along with its associated individual detailed report (Form 6180.54). 

This information will be provided directly to the S&TC regional supervisory specialist of the region in 

which the event occurred, with copies provided to the RA, DRAs, and the S&TC Staff Director. A copy 
20 

also will be saved to a designated file on the FRA’s R drive. Appropriate regional follow up will then be 

expected with the ultimate findings/ actions taken reported back to HQ. The idea is to access and review 

the data, identify issues and trends (including any reporting discrepancies warranting correction), draw 

conclusions, and formulate possible recommendations for action. The designated S&TC HQ staff will 

create a “running” summary report of the pertinent information surrounding the events, sorted by region 

and by railroad, which will also be maintained in the file on the R drive. 

Criteria for reviewing and analyzing railroad-submitted rail equipment accident/incident reports that 

indicate a signal cause include:

Who: S&TC HQ staff (the S&TC regional supervisory specialists, their regional 

managers, or field inspectors may perform the same review as the need may 

arise). 

When: Monthly review (info then provided to the region for follow up on a case-bycase basis). 

What: S&TC HQ staff shall conduct a monthly review of the data and email to the 

regions any issues for their follow up on a case-by-case basis; a “tally report” of 

events and actions taken will be maintained by HQ. 

Action: Inspection efforts or other appropriate follow up will be identified and 

performed. 

2. Highway-Rail Grade Crossing Accidents/Incidents:

The review of highway-rail grade crossing accidents/incidents is performed in order to identify all 

that may have involved active warning system malfunctions and sort them by cause, problem 

areas, and any trends that warrant particular follow up or attention. While there are relatively few 

grade crossing accidents associated with warning system malfunctions, the S&TC discipline still 

needs to be informed about their occurrence. We further need to identify and separate those 

events that are truly malfunctions in the sense of discipline technical or regulatory issues related to 

the functioning of the system (e.g., involving activation failure) in comparison to those that are 

related to different disciplines (e.g., involving hi-rail vehicles, on-track equipment, or other 

movements not expected to activate the warning system). Both categories are important, but they 

may warrant different types of responses and follow up by FRA. 

Railroads are required to report highway-rail grade crossing accident/incidents to FRA within 30 days 

following the end of month in which the event occurred using the Highway-Rail Grade Crossing 

Accident/Incident Report (Form 6180.57). (See 49 CFR §§ 225.11 and 225.19.) Railroads are also 

required to report to FRA within 24 hours, using a toll free telephone number, the occurrence of a 

highway-rail grade crossing accident/incident involving an activation failure. (See 49 CFR § 234.7.) As 

a result, FRA should have very timely knowledge of the occurrence of these types of events. The S&TC 

HQ staff will review grade crossing accident/incident reports being submitted by railroads that indicate a 

warning system malfunction, determine that any necessary telephonic notification was forthcoming, and 

review for incomplete or incorrect reporting (particularly related to the functioning of the warning 

system). Discrepancies in these reporting areas will be handled for correction with the reporting railroad. 

The data that should be retrieved includes the numbers and specifics associated with the previous full 

calendar year and the current year-to-date information. This data will be sorted monthly on a national 
21 

level by railroad, region, malfunction type, and qualifying codes and associated comments to identify 

involvement of bonafide malfunctions of an active warning system. The warning system conditions 

applicable and as reported in Block 33 of each detailed report (Form 6180.57) as confirmed include: 

greater than 60 seconds (possible false activation), less than 20 seconds, and no warning (both of the latter 

being activation failures by definition). 

The process begins by a HQ staff member using the Office of Safety Analysis Web site to retrieve all 

highway-rail grade crossing accident/incident data associated with confirmed warning system 

malfunctions. (See criteria below). 

A listing of all the qualifying events with pertinent information, to be accompanied by an associated 

individual detailed report for each incident (Form 6180.57), will be provided directly to the S&TC 

regional supervisory specialist, with copies provided to the RA and DRAs and the S&TC Staff Director. 

A copy also will be saved to a designated file on FRA’s R drive. Appropriate regional follow up would 

then be expected with the ultimate findings/actions taken reported back to HQ. The idea is to access and 

review the data, identify issues and trends (including any reporting discrepancies warranting correction), 

draw conclusions, and formulate possible recommendations for action. The designated S&TC HQ staff 

will create a running summary report of pertinent information surrounding the events addressed, sorted by 

region and railroad, that will be maintained in the file on the R drive. 

Criteria for reviewing and analyzing railroad-submitted highway-rail grade crossing accident/incident 

reports that indicate a signal cause include:

Who: S&TC HQ staff, S&TC regional supervisory specialists, their regional managers, 

and field inspectors, as the case may be. 

When: Monthly review (info then provided to the region on a case-by-case basis). 

What: S&TC HQ staff shall conduct a monthly review of the data and email to the 

regions any issues for follow up on a case-by-case basis; a tally report of events 

and actions taken will be maintained. 

Action: Inspection efforts or other appropriate follow up identified and performed. 

3. False Proceed Signal Failures:

The intention is to identify when and where false proceed signal failures occur and sort for top causes, 

specific problem areas (railroads, geographic, or topical), and any trends that warrant specific attention. 

Railroads are required to report false proceed signal failures to FRA by use of a False Proceed Signal 

Report (Form 6180.14) within 15 days following the event. (See 49 CFR § 233.7.) Railroads are to 

submit these reports to the FRA regional office of the region in which the railroad is headquartered or 

where their reporting office is located. The S&TC regional supervisory specialists then enter false 

proceed signal failure information pertaining to their respective regions into a national false proceed 

database, using the information on the report combined with the findings of their investigation of these 

incidents. Each quarter, the designated S&TC HQ staff member will review the data from national, 

railroad system, and regional perspectives and help identify possible trends, areas of concern, and/or any 

specific necessary focus. The S&TC regional supervisory specialists should already have knowledge of 

these issues from the regional perspective. Reporting concerns or deficiencies will also be identified and 

handled for correction. 
22 

The designated S&TC HQ staff will create a summary report for each region and submit it to the S&TC 

Staff Director for concurrence. These reports, consisting of a summary of findings and possible 

recommended actions, will be emailed to the S&TC regional supervisory specialists with copies provided 

to the RA/DRAs and the S&TC Staff Director. The regional personnel may then review these reports and 

make their own additional determinations. It is expected that the S&TC regional supervisory specialists 

will subsequently email a report with applicable specific guidance to their various inspectors. 

Conclusions and actions taken will then be summarized and provided to HQ with copies provided to the 

inspector’s RA/DRAs. 

For a national, railroad system, or regional review, start the process using the FRA secure Web site home 

page: https://safetydata.fra.dot.gov/securesite. Once logged into the system, start the following processes 

by selecting the Activation Failure/False Proceed program, then select the Browse/Edit/Update Record 

program under False Proceed. 

Steps for reviewing and analyzing reports of false proceed signal failures by railroads: 

Who: S&TC HQ staff, the S&TC regional supervisory specialists and their regional 

managers. 

When: Quarterly 

What: S&TC HQ staff shall access and review the report, create summary reports, 

and email their findings to the regions for their further review. Regions will 

email guidance to the inspectors, and will email their conclusions and 

actions taken to HQ with copies sent to their RA and DRAs. 

Action: Inspection efforts or other appropriate follow up identified and performed. 

4. Highway-Rail Grade Crossing Activation Failures:

The intention is to determine when and where activation failures occur and sort for top causes, specific 

problem areas (railroads, geographic, or topical), and any trends that warrant specific attention. Railroads 

are required to report activation failures to FRA by filing a Highway-Rail Grade Crossing Warning System 

Activation Failure Report (Form 6180.83) within 15 days following the event. See 49 CFR § 234.9. 

These reports are to be submitted by the railroads to the FRA regional office of the region where the 

railroad is headquartered or their reporting office is located. The S&TC regional supervisory specialists 

will then enter activation failure information pertaining to their respective region into a national activation 

failure database, using the information on the report combined with the findings of their investigation of 

these incidents. Each quarter, the designated S&TC HQ staff will review the information within that data 

from a national, railroad system, and regional perspective and help identify possible trends, areas of 

concern, and/or any specific necessary focus or other type recommendations. The S&TC regional 

supervisory specialists should already have knowledge of these issues from the regional perspective. 

Reporting concerns or deficiencies will also be identified and handled for correction. 

The designated S&TC HQ staff will create a summary report applicable to each region and submit it to 

the S&TC Staff Director for concurrence. These reports, consisting of a summary of findings and 

possible recommended actions, will be emailed to the S&TC regional supervisory specialists with copies 

provided to the RA and DRAs and the S&TC Staff Director. The regional personnel may then review 

these reports, make their own additional determinations, and it is expected the S&TC regional supervisory 

specialists will subsequently email a report with applicable specific guidance to their various inspectors. 
23 

Conclusions and actions taken will then be summarized and provided to HQ with copies provided to their 

RA and DRAs. 

For a national, railroad system, or regional review, the process begins by using the FRA secure Web site 

home page (https://safetydata.fra.dot.gov/securesite). Once logged into, start the following process by 

selecting the Activation Failure/False Proceed program then select the Browse/Edit/Update Record 

program under Activation Failure. 

Steps for reviewing and analyzing reports of highway-rail grade crossing activation failures by railroads: 

Who: S&TC HQ staff, S&TC regional supervisory specialists, and their regional 

managers 

When: Quarterly 

What: S&TC HQ staff shall access and review; create summary reports; email to 

the regions; further regional review; email guidance to the inspectors. 

Action: Inspection efforts or other appropriate follow up identified and performed. 

5. Signal Inspection Data:

The intention is to analyze past inspection efforts, findings, and outcomes and sort for units inspected, 

both the highest number and the most serious defective conditions found, violation recommendations, 

specific problem areas (national, railroads, or geographic), any trends that warrant particular attention, 

and to identify S&TC inspector activities relative to locations or subjects of concern. The data FRA will 

retrieve includes the above associated data within the previous 2 full calendar years and the current yearto-date information. This data will be sorted on a national level by railroad system, region, and inspector. 

The process begins by the Knowledge Management staff using a predetermined Special Analysis System 

(SAS) tool to retrieve all the S&TC HQ designated inspection information. The Knowledge Management 

staff will provide this information to the S&TC Staff Director and designated S&TC HQ staff on a 

quarterly basis by placing the data within a designated folder on the S&TC HQ server R drive. The 

S&TC Staff Director and/or designated S&TC HQ staff will in turn access and review the data, identify 

issues and trends, draw conclusions, and formulate possible recommendations. 

The designated S&TC HQ staff will create a summary report applicable to each region and submit it to 

the S&TC Staff Director for concurrence. These reports, consisting of a summary of findings and 

possible recommended actions, will be emailed to the S&TC regional supervisory specialists with copies 

provided to the RA and DRAs. The regional personnel may then review these reports and make their own 

additional determinations, and the S&TC regional supervisory specialists will subsequently email a report 

with applicable specific guidance to their various inspectors. Conclusions and actions taken will then be 

summarized and provided to HQ with copies provided to their RA and DRAs. 

Steps for reviewing and analyzing signal inspection data:

Who: Knowledge Management staff, S&TC HQ staff, the S&TC regional 

supervisory specialists, their regional managers, and field inspectors, as the 

case may be. 

When: Quarterly 

 
24 

What: Knowledge Management staff will provide a quarterly sort of inspection 

data. S&TC HQ staff will access and review, create summary reports, and 

email to the regions for their further review. Regions will email guidance to 

the inspectors, and email conclusions and actions taken to HQ with copies provided 

to their RA and DRAs. 

Action: Inspection efforts or other appropriate followup identified and performed. 

Preparation for Inspection or Investigation 

Before leaving their duty station to conduct inspections or investigations, inspectors should know what 

type of system they will be inspecting during the coming week. If an inspector is not fully familiar with 

the territory, he or she should review an inventory of the railroad line segment to be inspected. Further, 

the inspector should obtain and study the railroad’s timetable for the section to be inspected. The 

railroad’s timetable will provide information about the type of signal system installed, the maximum 

authorized speed, and any speed restrictions that might be in effect in the inspection area. Some 

timetables also list the locations of special protective devices such as slide fences and high-water 

detectors. 

Before leaving their duty station, inspectors will make sure that they have the necessary equipment to 

generate inspection report forms, and a copy of the current applicable portions of the Technical Manual 

identifying appropriate application of the regulations and the defect codes to be used to report defective 

conditions. Inspectors should also have a copy of the appropriate portions of the Technical Manual 

available to reference when questions of proper rules application arise. 

Notice of Inspection or Investigation 

A signal inspection requires advance planning by the FRA or State inspector and by the railroad officers 

and/or other employees that will accompany the inspector. Railroad officers need to arrange for 

employees to assist in the inspection and/or testing. The railroad must make travel arrangements and 

notify the affected employees. If on-the-rail transportation is required, arrangements must also be made 

to obtain a vehicle for such use. 

It is the inspector’s responsibility to notify the railroad in advance of when and where the inspection will 

be made. Care should be taken to not give excessive notice (i.e., 3+ weeks), but sufficient notice (i.e., 

1–2 weeks) should be given to the extent possible in order to enable the railroad officers to make suitable 

arrangements for a tentative inspection. 

While an unaccompanied inspection is permitted, such inspection activity is not encouraged and should 

only occur on a very limited basis. On an unaccompanied inspection, the inspector’s activities are limited 

to making visual inspections of signals, switches, and appliances. Since no railroad representative would 

be available to grant access to signaling equipment and circuits, the inspector would not be able to 

observe any tests, or inspect the relays, other signal apparatus, or the circuit plans inside of signal 

instrument cases and equipment housings. 

If a railroad officer declines to accompany or fails to provide someone else to accompany an inspector 

due to previous commitments, an inspector should arrange to make the inspection at a later date. In those 
25 

rare occasions when it appears that a railroad officer is deliberately thwarting all efforts of an inspector to 

make an inspection, the inspector should contact his or her regional supervisory specialist for assistance.

Time of Inspections and Investigations 

Normally, inspection activity will be conducted during the hours of the railroad signal employee’s regular 

working day. It is not FRA policy to require a railroad employee to work overtime making routine or 

regular inspections. The regular inspection day will commence at the railroad employee’s regular starting 

time and will include a lunch period consistent with that of the employee. The inspector will cease his or 

her inspection activity at a time that will permit the railroad employees to return to the point where they 

normally quit each day by their regular quitting time. Where the railroad employees accompanying the 

inspector are not returning to their headquarters daily, the inspection activity should cease at a time that 

will permit the railroad employees to reach the place where they are staying by their regular quitting time. 

This should not be construed as to encourage or permit an FRA inspector to require a railroad to cease 

work to correct a defective condition discovered during the day’s inspection. It is possible and very likely 

that at some time during inspection activity, a condition will be found that will require immediate 

corrective action, even though such action cannot be completed during the hours of a regular working day. 

At times during accident investigations, assessments, and special investigations, inspection activities may 

be conducted outside of the hours of the regular duty day. When such activities are performed outside of 

regular hours, the inspector will make appropriate arrangements with the railroad to provide employees 

who can perform tests and assist in the inspections. 

It is also important to note that inspections of onboard automatic train stop (ATS), train control (ATC), or 

cab signal devices (ACS), will sometimes require inspection activities at odd hours. Inspectors are 

encouraged to make ATS, ATC, and ACS inspections at times other than regular daytime duty hours to 

ascertain that proper tests and inspections are made on all locomotives during all duty shifts. The 

inspector shall receive approval from his or her regional supervisory specialist before performing 

inspections outside regular duty hours. 

Conference Prior to Inspection or Investigation 

Before starting an inspection or investigation, inspectors should introduce themselves to the parties who 

are accompanying them. The inspector shall obtain and make a list of the names and titles of all who will 

take part in the inspection or investigation. 

The inspector should explain the reasons for the inspection or investigation as being one or more of the 

following: 

1. Routine or regular inspection activity conducted to determine railroad compliance with the RS&I; 

Grade Crossing Signal System Safety; and or other Federal regulations. 

2. Inspection and testing of the signal systems in connection with an accident investigation. 

3. Inspection and testing of the signal systems in connection with the performance of a safety 

assessment of the railroad. 
26 

4. Inspection and investigation of a block signal application or an application for relief from a section 

of the regulations. 

5. Investigation of a reported false proceed signal failure or activation failure. 

 (Note: When making an inspection in connection with the investigation of a complaint, the inspector 

shall take particular care not to reveal the purpose of the inspection or the identity of a complainant.) 

All parties should be informed that the inspector’s objective is to determine compliance with Federal 

regulations in order to improve the safety of railroad operations, railroad employees, and the general 

public. 

Followup Inspection or Re-inspection 

A followup or re-inspection should be made: (1) after an assessment indicates that a problem exists on a 

particular railroad or portion of a railroad; (2) after an accident, and it has been determined that some 

prevalent condition existing on the railroad caused or contributed to the accident; (3) after an emergency 

order involving the railroad signal systems has been issued by the FRA; (4) where there has been a series 

of false proceed signal failures and/or highway-rail grade crossing activation failures caused by similar or 

related defective conditions; (5) where the previous inspections have found a higher-than-average number 

of defective conditions; and/or (6) where an order or BSAP or waiver approval has contained specific 

condition(s), and it needs be confirmed that the applicable condition(s) are met. 

Where an inspector finds, during a week’s work period or during an inspection of a fairly long line 

segment, that the ratio of defective conditions found to the number of signal units inspected, (the defect 

average or ratio) is higher than 15 percent, the inspector will schedule a re-inspection of the area having 

the high defect average. This line segment or signal installation might be a subdivision, a signal 

supervisor’s territory, a signal maintenance territory, or even a certain interlocking. The re-inspection 

shall be conducted within 60 days of the first inspection. Should the re-inspection find a defect average 

higher than 15 percent, another re-inspection will be scheduled. Such re-inspections will continue until 

the defect average falls to an acceptable level. 

The instruction to make a re-inspection within 60 days of any system wherein the inspector finds a defect 

average of more than 15 percent, does not preclude the inspector from making re-inspections on his or her 

own initiative. The inspector has the prerogative to reschedule any area for re-inspection, or more 

frequent inspection if, in the inspector’s judgment, such inspection is necessary to attain compliance and 

therefore safety. 

Refusal to Permit an Inspection or Investigation 

When trying to gain access to railroad property, inspectors may answer reasonable questions regarding the 

scope and purpose of the investigation. However, if access is denied, inspectors should ask the reason, 

leave the premises, and report the matter to their regional supervisors. The regional supervisors will then 

contact FRA HQ management and the Office of Chief Counsel for further instructions. Under no 

circumstances should inspectors engage in disputes with any railroad or shipper representative who 

refuses to permit an inspection. 
27 

Note: Reference the FRA General Manual for further guidance regarding interference with inspection or 

investigation activities, handling strikes or labor disputes, forcible resistance to inspections, use of 

credentials, and etc. 

Waiver of Responsibility 

The inspector shall not sign any form of release or agree to any form of waiver. If, after the inspector has 

pointed out FRA’s authority under the Signal Inspection Act of 1937 and the Federal Railroad Safety Act 

of 1970, a railroad still insists that an inspector sign some sort of release before entering upon the 

railroad’s property, the inspector shall suspend the inspection or investigation and promptly report the 

circumstances to his or her regional supervisory specialist. 

The inspector may sign a visitor’s register, property pass, or any form or book that the railroad uses to 

control entry and movement of persons on its property, so long as such signature does not constitute any 

form of waiver or release of prosecution or liability. 

Unusual Problems or Incidents 

Should the inspector encounter an unusual condition or situation that is questionable, but is not covered 

by regulations or guidance issued by FRA, the inspector should carefully weigh any action he or she 

takes. 

If the condition or situation clearly represents a danger to the public, railroad employees, or to the 

operation of trains, the inspector is expected to take action to ensure that the danger is mitigated. The 

inspector should notify his or her regional supervisory specialist and give full details of the situation as 

soon as possible. 

If the condition or situation does not represent an imminent danger to the railroad, its employees, or the 

general public, the inspector should contact his or her regional supervisory specialist and obtain advice 

and further guidance. 

Cooperation of Personnel with Industry and other Governmental Agencies 

The inspector should maintain a cordial relationship with the railroads, the manufacturers of railroad 

signaling equipment, and other governmental agencies. However, an inspector should not offer help or 

cooperation on any project or investigation without specific authorization of the Regional Administrator, 

Deputy Regional Administrator, or regional supervisory specialist. The regional supervisory specialist 

shall not authorize any such cooperation without specific authority from the Regional Administrator’s 

office. 
28 

Chapter 3 – Gaining Compliance

Purpose 

The purpose of this chapter is to provide guidance to Federal and State personnel for planning and 

conducting inspections and other related activities for determining appropriate levels of compliance with 

the Federal regulations. 

Regular Inspections 

Each inspector will sufficiently cover his or her inspection territory to assure that each railroad and/or 

system is inspected on a regular basis. However, the inspector shall direct his or her efforts to the 

railroads or areas that are most in need of improvement as indicated by previous inspection defect ratios, 

accident data, and/or the occurrences of false proceed signal failures and activation failures of highwayrail grade crossing warning devices. 

Each inspector has been furnished an S&TC Technical Manual. The technical manual provides detailed 

technical guidance covering the proper application of the S&TC regulations (primarily Parts 233, 234, 

235, and 236). 

In line with the guidance provided by the technical manual and general compliance policy, and because it 

is necessary to direct resources toward areas that are most in need of an inspector’s attention, the 

inspection program will emphasize re-inspection within 60 days of those systems where high-defect ratios 

are noted. Major test points for ACS, ATS, and ATC systems should be inspected monthly. Minor test 

points at outlying points should be inspected at least once every 6 months. Moveable bridges that are 

protected by an interlocking signal arrangement should be inspected at least once annually. 

The defect average is determined by dividing the number of defective conditions cited by the number of 

units inspected. 

By following these guidelines, FRA will be involved with systems that exhibit the highest percentage of 

defective conditions and on railroads where the most improvement in safety can be attained. Systems 

having excellent compliance levels will normally not be scheduled for re-inspection unless it is needed in 

connection with the investigation of accidents, complaints, applications, false proceed signal failures, 

highway-rail grade crossing activation failures, and assessments or other special assignments. 

Each inspector should strive to average at least one inspection per workday, except when on leave, 

performing a particular investigation or special assignment or completing the associated reports, or in 

training. 

 
29 

To assure the quality of inspection activity, the following guidelines are provided: 

 - S&TC Inspection Task - Time Allowance Table - 

Note: Times are shown as averages and they will vary in relation to system and 

equipment complexity and unit count

Inspection Task Time Allowed

Inspect each signal 20 minutes 

Inspect each switch 20 minutes 

Inspect each time locking circuit, 

approach locking circuit, 

route locking circuit, cut section, slide fence, 

dragging equipment 

detector, etc. 

20 minutes 

Inspect each ATC, ATS, or ACS equipped 

locomotive 30 minutes 

Inspect each ATC, ATS, or ACS inductor, 

acknowledgement loop, or test loop 10 minutes 

Inspect each highway-rail grade crossing 

warning device 45 minutes 

Inspect each record of test 2 minutes 

Investigate – BSAP 3 days 

Investigate – Complaint 3 days 

Investigate – False Proceed 2 days 

Investigate – Activation Failure 2 days 

It is the responsibility of each regional supervisory specialist to provide technical guidance to the 

inspectors in his or her region to effectively direct the safety program. Each regional supervisory 

specialist shall devise systems of monitoring the safety program to assure satisfactory progress, and will 

coordinate technical aspects of the program with appropriate S&TC HQ staff. 

Conducting an Inspection or Investigation 

An S&TC inspector’s primary duty is to perform effective inspections and investigations to ascertain 

whether the railroads are installing and maintaining their signal and train control systems, to include 

highway-rail grade crossing active warning systems, in compliance with S&TC regulations. The S&TC 

inspector is also expected to monitor the railroads’ activities to see that they are properly reporting as 

required by Parts 233 and 234, and to see that the railroads are complying with regulations governing the 

discontinuance and/or material modification of railroad signal systems (Part 235). 
30 

The inspections for compliance with Parts 234 and 236 require the inspector to visually inspect the signal 

systems and observe railroad personnel in the performance of tests to detect systems, devices, and 

apparatus that fail to meet the requirements of the regulations. It is important to note that the Federal 

regulations are minimum requirements and that many railroads have more stringent rules than FRA. The 

inspector is advised that he or she can enforce only FRA’s rules and standards. 

The inspector should always ascertain whether the railroad employees are using test equipment that is in 

suitable condition to make the required tests. Further, the inspector shall take care that no tests are 

performed that will imperil the safety of an approaching train or of highway users, or of a train that is 

within the limits of a system where tests are being conducted. For instance, ground tests shall not be 

conducted while a train is approaching passing over or passing by any switch or signal of an interlocking 

or controlled point. An inspector should be careful when ground tests or locking tests are being made, 

since such tests often affect control circuits at an adjoining interlocking or controlled point. An inspector 

should also be careful that testing does not create inappropriate highway-rail grade crossing active 

warning system malfunction. 

The inspection should be started at a particular point, (e.g., the end of the inspector’s territory, the end of 

the railroad’s signal territory, where the previous day’s inspection ended, etc.). The inspector should take 

each signal and/or switch location in turn, inspecting plans, equipment, and apparatus. 

The inspector should ask the railroad’s employees to make appropriate tests on the various apparatus and 

circuits of the systems under inspection. The inspector should not personally perform tests on the 

railroad’s signal systems, but should observe the tests made by the railroad’s employees to ascertain that 

the tests are made in accordance with the railroad’s instructions and the requirements of FRA’s 

regulations, that the apparatus being tested meets the requirements set by the regulations, and that the 

apparatus tested is in condition to perform its intended function. An inspector shall neither require nor 

permit a railroad employee to perform a test that will imperil the safety of train movements, highway 

users, or otherwise create an unsafe condition. 

The inspector shall point out each condition found that does not comply with the Federal requirements 

and shall notice what corrective action is taken by the railroad representatives and employees. The 

inspector shall make notes and keep track of the equipment inspected and the defective conditions noted 

during the inspections. 

In no case shall an inspector require or permit a railroad to leave uncorrected a condition that might 

imperil the movement of a train or engine. If it is evident that the railroad’s representative accompanying 

the inspector intends to leave a dangerous condition uncorrected, even after the inspector points out the 

inappropriateness of doing so, the inspector shall take immediate action to contact a higher official of the 

railroad and make the railroad aware of the condition. Should this course of action fail to achieve the 

needed corrective action, the inspector should immediately communicate the particulars of the situation to 

his or her regional supervisory specialist or other regional manager. 

Conference During and After an Inspection or Investigation 

After the day’s inspection activity on a railroad is finished, the inspector will make out his or her 

inspection reports, listing each defective condition he or she noted during the day’s work. The inspector 
31 

will then go over each item listed on the inspection reports with the railroad representative to make sure 

that the representative understands each item listed on the report(s) as defective, the location of each such 

condition, and what sort of corrective action is indicated. A copy of each inspection report will be given 

to the railroad’s representative before the inspector departs from the railroad’s property. 

Special Inspections and/or Assessments 

Special inspections, team inspections, and/or assessments are special inspections conducted to develop 

sufficient information to prepare a detailed evaluation of all or a major portion of a railroad system. All 

special inspection activities will be governed by the current instructions issued by FRA HQ for the 

conductance of such projects. 

Before starting to make inspections in connection with an assessment, the inspector should review all of 

the requirements of this chapter and be prepared to obtain sufficient information to complete his or her 

narrative report. 

Assessments will normally be assigned by the Associate Administrator for Railroad Safety/Chief Safety 

Officer, and in most cases, will involve more than one region. However, this does not prohibit the 

Regional Administrator from assigning an assessment on a railroad on a regional basis. 

Inspection reports shall be submitted for all inspections using the appropriate predetermined source code. 

All conditions that are not in accordance with the requirements of the regulations shall be duly reported 

on an Inspection Report Form F6180.96. During assessments or special inspection activities, violation 

reports will be filed in accordance with the instructions governing the conductance of such projects. 

An assessment narrative report shall be prepared by the inspector and shall contain sufficient information 

to support the conclusions of the inspector as to the degree of compliance with FRA’s signal regulations 

found and the overall condition of the railroad’s signal and train control systems. Further, the report 

should contain logical recommendations to present to the railroad to affect an improvement in the 

condition of the railroad’s signal and train control systems. 

The narrative report should be broken up into sections, each covering a defined line segment. In most 

cases, each line segment can be defined by the limits of a subdivision or district. When describing the 

line segment in the report, it should be identified by division, subdivision or district, milepost limits, and 

major cities. In some cases, it may be appropriate to break up extremely long subdivisions into milepostto-milepost segments because of different types of signal systems installed on the subdivisions (such as 

100 miles of ABS and 150 miles of TCS). 

Each line segment should be identified as to the type of signal systems installed, the maximum authorized 

speed, the number and kind of trains per day (passenger-freight), whether Amtrak operates over this line 

segment, and the amount of hazardous materials transported over the line segment. To provide further 

guidance during assessment activities, the following will provide a basic list of items an inspector should 

obtain or note. This list should not be considered as all inclusive, and the administrator or team leader of 

the assessment may require additional information. The inspector must be alert for special circumstances 

or conditions to be included in his or her assessment report, as follows: 
32 

 Note the size of territories of the signal maintainers, inspectors, and supervisors. Does each 

employee appear to have enough time to do the things he or she is supposed to be performing, or 

is his or her territory or area of responsibility so large as to make it impossible to perform all of his 

or her duties? The inspector should be alert and observe the safety consciousness and work habits 

of the employees so that he or she can adequately address the issue in the narrative report to be 

submitted at the end of the assessment. 

 Note the tools, test equipment, and material furnished to the signal maintainers and inspectors. 

Are the tools sufficient and in good condition? Are such items as the meters, shunt wires, relay 

test sets, and insulation resistance test sets adequate and appropriate to make proper and 

meaningful tests? Are the materials furnished adequate and appropriate to make the necessary 

repairs and replacements to keep the signal systems in good repair and functioning properly? 

 The inspector should interview the railroad’s signal department employees during his or her 

inspection activities to determine the level of training the railroad is furnishing its employees. It 

should be noted if the training is available for newly hired employees and older employees who 

were hired before the training program began. 

 Inspect the records of tests and determine whether the required tests are being properly performed 

on a timely basis. Ask signal maintainers and inspectors to perform a variety of tests to determine 

if they are properly trained and know how to make the required tests. 

 Note the general condition of the signal systems during the inspection activity. While the 

Inspection Report Form (F6180.96) will show the defective conditions found, it will not indicate 

such conditions as rusted out and/or deteriorated instrument housings, equipment in need of 

painting, rotting poles and crossarms, and brush growing under pole lines. 

 When the assessment includes the inspection of locomotive onboard ACS, ATS, and ATC 

devices, the inspector should make inspections and observe tests of each device. The inspector 

should also note the overall condition of the locomotive equipment. The inspector shall cite all 

conditions not in compliance with the Federal regulations on an inspection report and file violation 

reports when appropriate. He or she should also determine, through casual interviews, what type 

of training the railroad provides the personnel who maintain and test the onboard devices. Further, 

the inspector should try to determine if the railroad is complying with the Hours of Service Act as 

it pertains to employees performing departure tests, daily or after trip tests, or periodic tests of the 

onboard devices. 

 When making the final assessment report, the inspector should determine: 

o His or her overall defect ratio (defects cited divided by the number units inspected) 

o A breakdown of what the defects were 

o How many reports recommend violation 

o A breakdown of what the violations were 

o How many false proceed signal failures and activation failures have occurred in the area 

inspected within the last 2 years 

o Whether the defective conditions noted cause or contribute to other signal system or 

equipment failures 
33 

o The overall condition of the systems inspected 

o The overall condition of the signal employee’s qualifications and training, etc. 

Special Investigations 

Special investigations are assigned by the Regional Administrator, his or her representative, or by HQ 

staff through the Regional Administrator. There are at least five different types of investigations that 

inspectors routinely make. They are: 

 

1. Accident Investigations 

2. Complaint Investigations 

3. Block Signal and Waiver Applications 

4. False Proceed Signal Failure Investigations 

5. Highway-Rail Grade Crossing Activation Failure Investigations 

Inspectors may also be assigned other types of specific special investigations as the need arises. 

Accident Investigation 

Accident investigations will normally be assigned by the Associate Administrator for Railroad 

Safety/Chief Safety Officer. This does not prohibit the Regional Administrator from assigning accident 

investigations on a regional basis. Technical bulletins have been issued that define the types of accidents 

to be investigated and the procedures to be followed when making such investigations. Inspectors should 

also refer to the latest guidance found in FRA’s General Manual. 

If an S&TC inspection is made during the investigation of an accident, the inspector shall complete an 

Inspection Report Form F6180.96. The appropriate source code on the inspection report shall be shown. 

If the accident that is under investigation has been assigned an accident investigation number by HQ or by 

the region, the number shall be entered in the space titled “File Number.” Refer to the Railroad 

Inspection System for Personal Computers (RISPC) program for specific instructions concerning Form 

F6180.96. 

Complaint Investigation 

Complaints must be acted upon as soon as possible in keeping with the priorities and procedures 

contained in this manual and FRA’s General Manual. 

The regional supervisory specialist will establish priorities regarding the action to be taken on individual 

complaints. Complaints alleging the existence of eminent danger shall be accorded the highest priority. 

High priority shall also be given to complaints alleging conditions which appear to be serious safety 

concerns. 

If an oral complaint is made to an inspector during the course of an inspection, he or she should act on it 

to the extent possible as part of that inspection. If additional days will be involved in investigation of the 

complaint, the inspector must contact the regional specialist for guidance on any further handling of the 

complaint. 
34 

When acting on a complaint, the inspector should fully investigate the facility or systems involved in the 

alleged unsafe condition and/or noncompliance with FRA regulations. 

The procedures for handling complaints are: 

 Upon receipt of a written complaint, the Regional Administrator, or a member of his or her staff, 

will obtain a control number (complaint file number from CCM) to be used on all correspondence 

concerning the complaint, as well as the report of the investigation of the complaint. 

 Complaints that are received at FRA HQ will be assigned a control number before being sent to 

the applicable regional office for investigation. 

 The regional supervisory specialist will assign and schedule the investigation. For complaints 

directly received by the region, when the investigation is completed, the regional supervisory 

specialist will review the inspector’s report and prepare a closeout letter for the Regional 

Administrator’s signature. It would be helpful if a copy of the completed closeout letter and the 

inspector’s report is forwarded to the S&TC HQ staff for their information and for the purpose of 

recognizing possible trends or systemic issues. For complaints received by headquarters, HQ staff 

will prepare an interim response to be provided to the complainant, and the complaint will be 

assigned to the applicable region for investigation. When the investigation is complete, the 

regional supervisory specialist will review the inspector’s report and forward the report with 

applicable attachments to the S&TC HQ staff for preparation of a closeout letter. A copy of the 

subsequent closeout letter shall be provided to the region for their information and files. 

 The complaint should be evaluated to determine if the alleged violation or danger exists. The 

inspector should call or contact the complainant and obtain details of the alleged violation or 

danger. It may be desirable to meet with the complainant in person if possible. 

 When a regional or State office receives an oral complaint, in person or by telephone, action must 

be taken. This action can take the form of a formal investigation or be handled very much like a 

regular inspection. 

 If it is determined that a violation of FRA regulations or danger might exist, an investigation shall 

be scheduled as soon as practicable. If there appears to be an imminent danger to the operation of 

trains, to railroad employees, or to the general public, immediate action must be taken to mitigate 

such danger. 

 The investigation shall be conducted in accordance with the instructions in this manual. 

Normally, the investigation should be in detail and cover not only the alleged violations and/or 

dangerous conditions, but also the other facilities and systems in the immediate area. 

 After a field investigation of all of the allegations has been completed, the inspector will prepare a 

written narrative report describing the facility or system that was inspected, the conditions found, 

what corrective action was taken by the railroad, and what action was taken by the inspector. An 

inspection report, Form FRA F6180.96, shall be submitted to cover each such inspection using 

appropriate source code and the complaint file number shall be shown in the space titled, “File 

Number.” If allegations of a violation of FRA’s signal regulations are found to be valid, a 
35 

violation report should be submitted in most instances. The inspector will forward the original 

report with all documents and backup materials to the regional office for review and handling as 

described above. 

Block Signal or Waiver Application Investigation 

Part 235, Instructions Governing Applications for Approval of a Discontinuance or Material Modification 

of a Signal System or Relief from the Requirements of Part 236, specifically provides the mechanism for a 

railroad to make application to discontinue or materially modify signal systems on its property, or to ask 

for relief from any of the requirements of Part 236, the RS&I. 

 

A thorough field investigation and a complete report are required on each application for relief from the 

requirements of the RS&I (RS&I-Ap) and on each application for approval of a discontinuance or 

material modification of a block signal system, interlocking, ATS, ATC, and ACS device (BS-Ap). 

The information submitted by the railroad in accordance with the provisions contained in Part 235 will 

form the basis for the investigation and report on each BS-Ap and RS&I-Ap. This information should be 

checked at the time of investigation to ensure that it is correct for use in the preparation of the report and 

in order that additional information, if necessary to complete the report, may be obtained promptly. Two 

copies of this information are provided with each application assigned for field investigation. One copy is 

to be retained in the inspector’s file. 

Each application should be promptly investigated and the field investigation report should be prepared 

and mailed in time to reach HQ staff prior to the closing date shown on the assignment. 

False Proceed Signal Investigation 

Upon receipt of a False Proceed Signal Report (Form FRA F6180.14), the regional supervisory specialist 

shall determine if the false proceed signal failure occurred within his or her region. If it did not, the 

regional supervisory specialist should immediately furnish a copy of the report to the region in which the 

false proceed signal failure did occur. All reports of false proceed signal failures shall be investigated, the 

difference being only the degree of investigation warranted. The regional supervisory specialists, for all 

occurrences within their respective regions, shall ensure the following procedures are followed. 

Informal Investigation 

Each false proceed signal failure incident reported by a railroad shall receive, at a minimum, an 

“informal” investigation that shall consist of at least an inquiry to ascertain that the information submitted 

is accurate and complete and that the cause reported is appropriate. In addition, a determination shall be 

made as to whether any reportable accident/incident (as defined in 49 CFR § 225.5) occurred as a result of 

the false proceed and whether any further “formal investigation” is necessary. Each informal 

investigation shall include a verbal conversation between the regional supervisory specialist or an S&TC 

inspector, and an appropriate representative of the railroad (i.e., signal supervisor, signal manager, etc.). 

The findings of each informal investigation shall be recorded on the “False Proceed Signal Failure 

Informal Investigation” form. 
36 

Any cause reported by the railroad on the false proceed signal report is to include sufficient narrative 

explanation of the occurrence and should properly identify the type of system involved. If a sufficient 

narrative explanation is not provided, and/or the informal investigation reveals that another more specific 

cause is appropriate, that fact should be discussed with the railroad and the railroad should be asked to 

submit a revised report. If an agreement cannot be reached on the proper cause, the FRA database shall 

reflect the most applicable cause, and the discrepancy should be addressed on the “False Proceed Signal 

Failure Informal Investigation” form or within any subsequent written formal investigation report. 

Formal Investigations

Each false proceed that results in an accident/incident (as defined in 49 CFR § 225.5) shall be formally 

investigated. As part of the investigation process, a determination shall be made as to whether the 

National Response Center was notified within 24 hours, as required in 49 CFR § 233.5, and as to whether 

an accurate and complete Rail Equipment Accident/Incident Report (Form 6180.54) was submitted to 

FRA in accordance with 49 CFR § 225.11. The investigating inspector shall obtain a copy of the 

report(s), review it for proper reporting per the instructions contained in the FRA Guide for Preparing 

Accident/Incident Reports, and contact the railroad reporting officer to facilitate any necessary correction. 

If an agreement cannot be reached, the inspector’s narrative in his/her false proceed signal failure 

investigation report shall include a description of the circumstances. 

Additionally, a false proceed signal failure that the railroad describes as being caused by one or more of 

the following factors should normally be formally investigated: 

 Sand, rust, or other deposits on rail 

 Failure of relay 

 Failure of electronic device 

 Failure at an interlocking 

 Interference 

 Design error 

 Errors in connections or adjustments 

 Where the cause is undetermined 

However, if in any of these instances, the regional supervisory specialist determines that a formal 

investigation is not warranted, the regional supervisory specialist shall notify the Regional Administrator 

and the S&TC Staff Director (via email is acceptable). In that case, a “False Proceed Signal Failure 

Informal Investigation” form shall be completed that shall contain a brief explanation of the reason(s) 

supporting his or her determination. The explanation shall then be entered into the comments section of 

the report in the false proceed signal failure database. 

A narrative report must be prepared for each formal investigation of a false proceed signal failure. Each 

false proceed signal failure investigation report shall follow the guidelines established for completion and 

submission. The report shall be addressed to the Regional Administrator. A copy of the completed 

report, with any associated inspection and accident/incident report(s), shall be forwarded to the S&TC 

Staff Director. All associated inspection reports should indicate the correct source code for the inspection 

and the assigned file number. 

 
37 

File Numbers

Each reported false proceed signal failure occurrence shall receive a file number. The file number for 

each occurrence will begin with FP, followed by the two-digit calendar year in which it occurred, then the 

region number, followed by a sequential number for each occurrence within the region for the calendar 

year (e.g., FP11-6-1, FP11-6-2, etc.). 

Database Records

Each regional supervisory specialist shall ensure that all pertinent information regarding false proceed 

signal failures occurring within his or her region is entered into the false proceed database at least once 

each month. This database, which is an important tool for recording information pertaining to these 

events, as well as analysis of that data, is subject to review by numerous entities, including the public. 

Important fields in the database for which accurate data is essential include: 

1. Reported cause and FRA’s cause code (especially when FRA’s cause code differs from what was 

reported by the railroad); 

2. Whether the false proceed was formally investigated; 

3. Investigation file number; 

4. Record open or closed, and closed by whom; 

5. Remarks, if applicable, that include relevant or expanded information related to the cause of the 

false proceed and the corrective action taken; and that should identify specific types of equipment 

failures when applicable, for example: GRS B-1 relay; and, 

6. Whether an accident/incident was involved. In addition, it is important to ensure that the type of 

system in which the failure occurred is correctly entered in the database because occasionally the 

railroad’s report is incorrect. 

As soon as the FRA investigation (informal or formal) is completed and the regional supervisory 

specialist is satisfied with all database entries, the file must be closed. Partial information from each 

record will then be released onto the FRA public Web site by S&TC HQ staff. 

The regional supervisory specialist shall ensure that the completed false proceed signal reports, including 

a copy of the original Form FRA F6180.14 reported by the railroad, copy of associated inspection 

report(s), and any other associated documentation, are forwarded to the S&TC Staff Director in 

Washington, DC. The S&TC HQ staff shall then keep these records on file in the headquarters office. 

Activation Failure Investigation 

Upon receipt of a Highway-Rail Grade Crossing Warning System Activation Failure Report, the regional 

S&TC supervisory specialist shall determine if the activation failure occurred within his or her region. If 

it did not, the regional S&TC supervisory specialist should immediately furnish a copy of the report to the 

region in which the activation failure occurred. All reports of activation failures shall be investigated, and 

the results entered on the new “Activation Failure Form,” the difference being only the degree of 

investigation warranted. The new form is an electronic version in Microsoft InfoPath. A “Help” section 

with instructions is provided for each block that needs to be filled out on the form. The regional S&TC 

supervisory specialists, for all occurrences within their respective regions, shall ensure the following 

procedures are followed. 
38 

Informal Investigation

Each activation failure incident reported by a railroad shall receive, at a minimum, an “informal 

investigation,” that shall consist of at least an inquiry to ascertain that the information submitted by the 

railroad is complete and accurate and that the cause reported is appropriate. In addition, a determination 

shall be made whether any accident/incident (as defined in 49 CFR § 225.5) occurred as a result of the 

activation failure, and whether any further “formal investigation” is necessary. Each informal 

investigation shall include a verbal conversation between the regional S&TC supervisory specialist, or an 

S&TC inspector, and an appropriate representative of the railroad (i.e., signal supervisor, signal manager, 

etc.). The findings of each informal investigation shall be recorded on the “Activation Failure Form” with 

the box checked to indicate an informal investigation. 

Any cause reported by the railroad as “Other, miscellaneous” on the activation failure report (Form FRA 

F6180.83) is to include sufficient narrative explanation in the comments section of the report. If a 

sufficient narrative explanation is not provided, and/or the informal investigation reveals that another 

more specific cause is appropriate, that fact should be discussed with the railroad and the railroad should 

be asked to submit a revised report. If agreement cannot be reached on the proper cause, the FRA 

database shall reflect the most applicable cause and the discrepancy should be addressed on the 

“Activation Failure Form.” 

Formal Investigation

Each activation failure that results in an accident/incident (as defined in 49 CFR § 225.5) shall be 

formally investigated. An accident/incident is defined as an impact between on-track railroad equipment 

and an automobile, bus, truck, motorcycle, bicycle, farm vehicle, or pedestrian at a highway-rail grade 

crossing. As part of the investigation process, a determination shall be made whether the National 

Response Center was notified within 24 hours, as required in 49 CFR § 234.7, and whether a complete 

and accurate Highway-Rail Grade Crossing Accident/Incident Report (Form 6180.57) was submitted to 

FRA in accordance with 49 CFR § 225.11. The investigating inspector shall obtain copy of the report(s), 

review for proper reporting per the instructions contained in the FRA Guide for Preparing Accident/ 

Incident Reports, and contact the railroad reporting officer(s) to facilitate any necessary correction. If 

agreement cannot be reached, the inspector’s narrative in his or her activation failure investigation report 

shall include description of the circumstances. 

Additionally, an activation failure that the railroad indicates was caused by one or more of the following 

factors should also be formally investigated: 

 Sand, rust, or other deposits on rail 

 Failure of relay 

 Failure of electronic device 

 Interference 

 Design error 

 Errors in connections or adjustments 

 Where the cause is undetermined 

However, if in any of these instances, the regional S&TC supervisory specialist determines that a formal 

investigation is not warranted, the specialist shall notify the Regional Administrator and the S&TC Staff 
39 

Director (via email is acceptable). In that case, an informal investigation shall be completed which shall 

contain a brief explanation of the reason(s) supporting his or her determination. The explanation shall 

then also be entered into the comments section of the report in the activation failure database. A regional 

S&TC supervisory specialist, on a case-by-case basis, may also identify the need for formal investigation 

of any event of any other cause(s). 

A report must be prepared for each investigation of a highway-rail grade crossing warning system 

activation failure. If it is determined that an activation failure did not take place, the appropriate box 

“Invalid Report” must be checked on the form to indicate such. Each activation failure investigation 

report shall follow the new form guidelines established for completion and submission, a “Help” section 

accompanies each field of the new form for clarity of completion. A copy of the completed report, with 

all associated attachments including inspection reports, accident/incident report(s) and the 6180.83 report, 

shall be forwarded to the S&TC Staff Director no later than the month following the completed 

investigation. All associated inspection reports should indicate the correct source code for the inspection 

and the assigned file number. 

File Numbers 

Each reported activation failure occurrence shall receive a file number. The file number for each 

occurrence will begin with AF, followed by the calendar year in which it occurred; then the region 

number. For each investigation, the region number will be followed by a sequential number for each 

occurrence within the region for the calendar year (e.g., AF05-6-1, AF05-6-2, etc.). 

Database Records

Each regional S&TC supervisory specialist shall input all pertinent information regarding reported 

activation failures occurring within his or her region into the activation failure database at least once each 

month. This database, which is an important tool for recording information pertaining to these events, as 

well as analysis of that data, is subject to review by numerous entities, including the public. Important 

fields in the database for which accurate data is essential include: 

1. Reported cause code and FRA’s cause code (especially when FRA’s cause code differs from that 

which was reported by the railroad); 

2. Whether the activation failure was investigated (always yes); 

3. Date of investigation; 

4. Investigation file number; 

5. Record open or closed, and closed by whom; 

6. Remarks, if applicable, that include relevant or expanded information related to the cause of the 

activation failure and the corrective action taken; and 

7. Whether an accident/incident was involved. 

As soon as the FRA investigation (informal or formal) is completed and the regional S&TC supervisory 

specialist is satisfied with all database entries, the file must be closed, in any case no later than the quarter 

following the month the AF investigation was completed. Partial information from each record will then 

be released onto the FRA public web page by S&TC headquarters staff. 

 
40 

By no later than the end of each month, the regional S&TC supervisory specialist shall gather all of the 

previous month’s completed activation failure reports and forward them to the S&TC Staff Director in 

Washington, DC. The S&TC headquarters staff shall then keep these records on file in the headquarters 

office. 

Conducting Interviews 

Inspectors will, from time to time, need to conduct an interview of a railroad employee or other person in 

connection with an investigation of an accident, complaint, application, false proceed signal or activation 

failure, assessment, etc. Such interviews shall be conducted within the guidelines set forth in the General 

Manual. 

The interview shall be conducted in a businesslike manner, with no frivolity. The person interviewed will 

be treated courteously and with respect. The questions should be pertinent to the investigation and not be 

made in a leading manner. The idea of the interview is to get that person’s viewpoint about the subject or 

what happened. The interview should be audio-recorded if at all possible. Good notes should be kept of 

the interview so that an accurate report of interview can be prepared. 

The inspector will give full credence and consideration to the comments and statements of the person 

being interviewed. The inspector will weigh those comments and statements in concert with established 

facts and the comments and statements of other persons. 

Determining When and What Enforcement Action Is Necessary 

FRA does not have to take a formal enforcement action every time it discovers or learns of a condition of 

noncompliance with the Federal railroad safety laws and regulations. FRA has enforcement discretion, 

and it can choose which cases to pursue for civil penalty or other form of enforcement based on available 

resources and on what it believes to be the best method of promoting compliance. Moreover, when FRA 

decides that enforcement action is warranted, it has a range of enforcement tools (discussed below) and 

has the authority to choose those best suited to the circumstances. One of these tools—the emergency 

order—can be used to address an immediate hazard, even if no existing Federal regulation or law has been 

specifically violated. 

The existence of this wide enforcement discretion, concerning when and what enforcement action is 

necessary, calls for general guidelines to ensure effectiveness, fairness, and an acceptable level of 

consistency in the exercise of that discretion. The purpose of these guidelines is not to dictate absolute 

identical treatment of like situations; that would be unrealistic and would require a false assumption that 

each of the many variables going into an enforcement decision could objectively and accurately be 

quantified. Instead, the purpose of these guidelines is to control the subjective elements of this process, as 

much as is feasible, by requiring that those making enforcement decisions weigh the same factors and 

make full, uniform use of the information available to them. In this way, the appropriate enforcement tool 

is most likely to be applied, responsible discretionary judgments are made, and an acceptable level of 

consistency is achieved. Application of these factors should preclude abuses of discretion such as basing 

an enforcement decision on personal bias, or failure to enforce the law because of a personal aversion to 

action and/or the “extra work.”
41 

FRA’s Statement of Agency Policy Concerning Enforcement of the Federal Railroad Safety Laws 

(49 CFR Part 209, Appendix A) stresses that discretion is exercised at the field and regional levels. 

Although inspectors make initial determinations on the need for enforcement action, regional personnel 

play an active role in reviewing those determinations with an eye toward effectiveness and consistency. 

Moreover, regional supervisory specialists play a primary role in ensuring that field inspectors have the 

data necessary to make effective and appropriate enforcement decisions. The regional supervisory 

specialist, for example, periodically analyzes the relevant data on accidents, incidents, and inspections to 

detect patterns or problem areas at the regional, railroad, or office level. This information should be used 

not only in deciding where to inspect but, as discussed below, is also used in deciding when and what 

enforcement action is necessary. Office of Railroad Safety headquarters personnel are, of course, 

responsible for spotting national trends in the data that warrant particular levels of enforcement action and 

for providing guidance to the regional and field staffs on difficult enforcement policy issues. 

FRA’s policy statement sets forth key factors to be considered in making enforcement decisions. The 

following information in this chapter should be considered when weighing factors regarding any S&TC 

enforcement decisions. 

1. The inherent seriousness of the condition or action. 

2. The kind and degree of potential safety hazard the condition or action poses in light of the 

immediate factual situation. 

3. Any actual harm to persons or property already caused by the condition or action. 

4. The offending person’s (i.e., railroad or individual) general level of current compliance as 

revealed by the inspection as a whole. 

5. The person’s recent history of compliance with the relevant set of regulations, especially at the 

specific location or division of the railroad involved. 

6. Whether a remedy other than a civil penalty (ranging from an individual warning up to an 

emergency order) is more appropriate under all of the facts. 

7. Such other factors as the immediate circumstances make relevant. 

The exercise of this discretion at the field and regional levels is a vital part of the enforcement process, 

ensuring that the exacting and time-consuming civil penalty process is used to address those situations 

most in need of the deterrent effect of available penalties. 

Parts 233, 234, 235, and 236 contain the minimum standards by which the Nation’s railroads must design, 

install, test, and maintain their signal and train control systems and highway-rail grade crossing active 

warning systems. The railroads may adopt more stringent requirements than these regulations specify, 

which some railroads have done. The S&TC inspector is required to take exception to any condition that 

does not meet the requirements of these regulations. However, at the same time, the S&TC inspector 

cannot take exception to a condition just because it does not comply with the railroad’s standards, or 

because the inspector does not like the way a signal circuit or apparatus is designed, installed, tested, or 

maintained. The S&TC inspector’s authority extends only to the enforcement of the Federal regulations. 

Should an inspector find or note a hazardous condition that is not covered by the S&TC Federal 

regulations, he or she should orally bring it to the attention of the railroad and report the condition to their 

regional supervisory specialist. 

All defective conditions noted by the inspector shall be reported on the FRA inspection report, using the 

defect codes contained within the RISPC program and as listed in the applicable Technical Manual 
42 

section. Only these defect codes may be used. The inspector is encouraged to add clarifying notations of 

particular deficiencies, especially when violations are recommended; however, inspectors are not 

permitted to make up their own defect codes. 

Handling of Defective Conditions 

The inspector will inspect and observe the performance of railroad tests of signal systems for compliance 

with 49 CFR Parts 233, 235, and 236, and for highway-rail grade crossing active warning systems for 

compliance with 49 CFR Part 234. The objective of the inspector’s regular inspection activity will be to 

find and cause to be corrected any condition that does not meet the requirements of these regulations. 

In their inspection activities, inspectors shall be guided by the information contained in the applicable 

Technical Manual portions regarding the application of the rules and regulations contained in Parts 233, 

234, 235, and 236. 

The Technical Manual provides a rule-by-rule analysis of the correct application of the rules and 

regulations, and what each rule means and how its requirements are to be applied. When making regular 

S&TC inspections, the guidelines provided by the appropriate Technical Manual portion shall be applied 

and followed. All defective conditions found will be cited as defects on an FRA inspection report and 

handled with the railroad for correction. When warranted, it will be appropriate for the inspector to issue 

an inspection report that recommends a violation. FRA has given its inspectors latitude to use their 

discretion to file violations as one of the tools to be used to obtain railroad compliance with the safety 

regulations, and the agency expects its inspectors to use that discretion wisely. For instance, violation 

reports may be justified for defective conditions that would normally be handled as citations of 

deficiencies (i.e., defects) by showing a related noncompliant trend on a railroad, or by showing that the 

railroad failed or refused to correct defective conditions cited on a previous inspection report. 

Defective Conditions Not Cited as a Violation 

When, in the judgment of the inspector, the defective conditions found do not represent an imminent 

hazard to the operation of trains, do not present a danger to the railroad’s employees or the general public, 

do not appear to be a trend or pattern of defective conditions, and are not associated with a specific 

condition previously cited for correction which has not been performed, the inspector should cite the 

defects on an inspection report while not recommending a violation. Subsequently, the inspector shall 

take such action as necessary to make sure the railroad corrects the defective conditions and brings its 

systems into compliance with the applicable regulations. 

Defective Conditions Cited as a Violation 

Noncompliance with the requirements in any section of Parts 233, 234, 235, and 236 can be cited as a 

violation. The following are guidelines for situations that—depending on conditions found, 

circumstances involved, or compliance history—violations are nearly always warranted: 

 When an inspector finds conditions that are not in compliance with the regulations, and in the 

judgment of the inspector, the conditions present an imminent hazard to movement of trains or the 

general public. 
43 

 When a condition is found during a re-inspection that was cited on a previous inspection report 

and can be clearly identified as having remained uncorrected since that previous inspection. The 

re-inspection must have been performed within 60 days of the previous inspection to support 

violation work. 

 When, during the course of an investigation of an accident, false proceed signal failure, or 

highway-rail grade crossing active warning system activation failure, the inspector finds that the 

accident or failure was caused by a defective condition that does not comply with the requirements 

of the regulations and a violation is warranted. For example, instances such as interference, failure 

to properly test after performing adjustments or repairs, failure to test after a vital component was 

replaced, etc. 

In order to increase and maintain appropriate and uniform enforcement of the regulations across the 

discipline, the following rule sections and associated deficiencies are provided as examples of noncompliance that in most instances warrant citing violations: 

§ 233.5 When a false proceed signal failure caused or contributed to an accident and the railroad fails 

to properly report the accident. 

 

§ 233.7 When the railroad fails to properly report a false proceed signal failure within the required 

time frame. 

§ 234.7 When an activation failure caused or contributed to a highway-rail grade crossing accident 

and the railroad fails to properly report the accident. 

§ 234.9 When the railroad fails to properly report an activation failure within the required time 

frame. 

§ 234.103 When the railroad fails to respond in a timely manner to a credible report of a malfunction of 

a highway-rail grade crossing active warning system. 

§ 234.105 When the railroad fails to notify a train crew of an activation failure condition prior to their 

operating over the affected crossing; or, when a duly notified train crew fails to operate their 

train in accordance with the alternative warning requirements associated with an activation 

failure. 

§ 234.106 When the railroad fails to notify a train crew of a partial activation condition prior to their 

operating over the affected crossing; or, when a duly notified train crew fails to operate their 

train in accordance with the alternative warning requirements associated with a partial 

activation. 

§ 234.107 When the railroad fails to notify a train crew of a false activation condition prior to their 

operating over the affected crossing; or, when a duly notified train crew fails to operate their 

 train in accordance with the alternative warning requirements associated with a false 

activation. 

 
44 

§ 234.203 When a control circuit that affects the safe operation of a highway-rail grade crossing active 

warning system does not operate on the fail-safe principle. 

§ 234.207 When the railroad fails to use due diligence in determining the cause of a highway-rail grade 

crossing active warning system failure, malfunction, or defective condition affecting the 

proper operation and/or ability of the system to warn highway users of an approaching train; 

or, when a railroad fails to conduct necessary adjustment, repair, or replacement without 

undue delay. 

§ 234.209 When an inspector finds a railroad is in noncompliance with this section. 

§ 234.215 When an inspector finds a highway-rail grade crossing active warning system with no 

standby power provided; or, the standby power is knowingly of insufficient capacity. 

§ 234.227 When the railroad fails to take appropriate action under § 234.105 where sand, rust, dirt, 

grease, or other foreign matter is known to prevent effective shunting. 

§ 234.229 When an inspector finds a train detection circuit so installed and adjusted that it does not 

detect a shunt of 0.06 ohm when the shunt is connected across the track rails at any location 

in the train detection circuit. 

§ 234.231 When an inspector finds a switch turnout in the detection circuit that is equipped with 

fouling wires fails to shunt during test of fouling section or switch circuit controller because 

both the fouling or shunt wires are not sufficient (broken or missing, or too small, corroded, 

or bad plug connection) to ensure proper operation of the train detection circuit as required in 

§ 234.227. 

§ 234.237 When an inspector finds a switch circuit controller interconnected with the highway-rail 

grade crossing warning system circuitry used as a reverse switch cutout circuit to be so 

maintained that the warning system can be cut out when the switch point is open 1 inch or 

more from the full reverse position. 

§ 234.267 When an inspector finds the railroad has not repaired or removed from service a conductor 

found with insulation resistance of less than 200,000 ohms. 

§ 235.5 When the railroad has failed to obtain FRA permission to make signaling changes that 

require FRA approval under the provisions of Part 235. 

§ 236.0 When an inspector finds that a railroad is scheduling and operating trains in noncompliance 

with provisions of this section and it is determined the maximum authorized speed is in 

excess of the speeds permitted by this section. 

§ 236.3 When an inspector finds an electro-mechanical, electro-pneumatic, or power interlocking 

cabinet is not sealed or locked to prevent someone from improperly manipulating the 

mechanical locking contained in the interlocking machine without breaking the seal or 

unlocking the cabinet. 

 
45 

§ 236.4 When an inspector finds a railroad is in noncompliance with this section. 

§ 236.6 When an inspector finds a circuit controller to be so maintained that the track circuit or 

control circuit is not opened or shunted when the switch point is open twice the distance 

specified by the requirement. 

§ 236.11 When an inspector finds a railroad not promptly making repairs to signaling devices that are 

found to be malfunctioning, if such delay contributed to or constituted a hazard to safety of 

train operation. 

§ 236.13 When an inspector finds a switch circuit controller or circuit controller associated with a 

spring switch to be so maintained that the track circuit is not opened or shunted or the 

 control circuit is not opened when the switch point is open twice the distance specified by 

the requirement. 

§ 236.16 When an inspector finds a main track electric lock releasing circuit to be so installed or 

maintained that it extends into the turnout beyond the heel of the switch points. 

§ 236.18 When an inspector finds that a railroad required to have done so has not developed and 

implemented a software management control plan; or where a process or procedure 

identified within the plan was not complied with, which results in an unsafe failure. 

§ 236.51 When an inspector finds that a track circuit is so installed that the removal of a rail or frog, 

or a car or engine standing on the track circuit, will not cause the associated track relay to be 

in deenergized position or device that functions as a track relay not in its most restrictive 

state. 

§ 236.55 When an inspector finds a dead section that exceeds 35 feet, or is longer than the shortest 

outer wheel base of a railroad locomotive operated over it and a special circuit is not 

installed to provide equivalent track circuit protection. 

§ 236.56 When an inspector finds a track circuit so installed and adjusted that the track circuit is not in 

deenergized position when a shunt of 0.06 ohm is placed across the rails at any location in 

the circuit. 

§ 236.57 When an inspector finds a main track circuit fails to shunt during test of fouling section or 

switch circuit controller because both the fouling or shunt wires are not sufficient (broken or 

missing, or too small, corroded, or bad plug connection) to perform their intended function. 

§ 236.58 When an inspector finds that a 0.06 ohm shunt placed on the rails in the fouling section does 

not properly shunt down the main track circuit because of missing, broken, or defective rail 

bonds on the fouling section. 

§ 236.60 When an inspector finds a new switch (installed after 2-26-84) with shunting circuit that 

does not open track circuit or control circuit. See § 236.60 in technical manual for definition 

of new switch. 
46 

§ 236.108 When an inspector finds the railroad has not repaired or removed from service a conductor 

found with insulation resistance of less than 200,000 ohms. 

§ 236.207 When an inspector finds an electric lock with an emergency release device that is not locked 

or sealed and it is not equipped with an effective latch-out device. 

§ 236.309 When an inspector finds an automatic interlocking approach circuit which activates approach 

or time locking, or approach track circuit , or a new power-operated switch (installed after 2-

26-84), where a loss of shunt of 5 seconds or less permits respectively the established route 

or route locking to be changed. 

§ 236.312 When an inspector finds an emergency release is provided to release bridge locking that is 

not kept locked or sealed and it is not equipped with an effective latch-out device. 

§ 236.314 When an inspector finds an electric lock on a hand-operated switch within the limits of an 

interlocking with an emergency release device that is not sealed and it is not equipped with 

an effective latch-out device. 

§ 236.327 When an inspector finds that a power-operated switch or movable point frog is so maintained 

that the switch will lock up when the point is open one-half inch or more.

§ 236.334 When an inspector finds that a point detector will assume the position corresponding to 

switch point closure when switch point is open one-half inch or more.

§ 236.342 When an inspector finds that a switch circuit controller which is connected to pipe-connected 

switch, derail, or movable-point frog; and, where an external switch circuit controller is 

added to a power-operated switch; is so maintained that the contacts assume a position to 

indicate the switch point is closed while switch point is open one-half inch or more. 

§ 236.410 When an inspector finds the railroad has not installed an electric lock or a signal to govern 

movement from an auxiliary track at a hand-operated switch that is required by this section 

to have such protection; an electric lock on a hand-operated switch is equipped with an 

emergency release device that is not locked or sealed and it is not equipped with an effective 

latch-out device; or, when an inspector finds that the approach or time locking is not 

effective due to a design error or other defective condition. 

§ 236.526 When an inspector finds the railroad failed to set wayside signal to display its most 

restrictive aspect when an associated roadway element is defective or missing, or that the 

railroad has restored the signal to normal operation before the defective or missing 

associated roadway element has been replaced or repaired. 

§ 236.553 When an inspector finds that a locomotive was used in the lead position in equipped 

territory, and that the cut-out device used to cut out the pneumatic portion of the apparatus

was not sealed; or, if locomotive is found on the ready track and is listed as available to be 

dispatched into equipped territory as the lead locomotive after a daily or after trip test, or a 

departure test, and such cut-out device is not sealed. 
47 

§ 236.566 When an inspector finds that a train was operated into equipped territory with a nonequipped locomotive; or, a locomotive with a device that was not in serviceable condition, 

on departure from its initial terminal. 

§ 236.567 When an inspector finds that a train has proceeded with a failed or cut-out device without 

making a report to the designated officer at the next available point of communications; or, 

such a train is permitted to proceed at speeds in excess of 79 mph with a cut-out or failed 

device. 

§ 236.586 When an inspector finds that a daily or after trip test has not been performed when required

and the equipped locomotive has been subsequently dispatched into equipped territory. 

§ 236.587 When an inspector finds the locomotive controlling the brakes has not received a proper 

departure test before leaving its initial terminal, before entering equipped territory where the 

 system is cut out between initial terminal and equipped territory, or when making more than 

one trip in a 24-hour period, at least once every 24 hours. 

§ 236.588 When an inspector finds a locomotive available for service that is equipped with automatic 

cab signal, train control, or train stop has not received a proper periodic test according to 

either an interval of not more than 2 months, or at least once every 92 days, whichever is 

applicable.

Railroad Action to Correct Defective Conditions 

Some railroad personnel have the mistaken idea that when a noncompliant or defective condition is cited 

on an inspection report, the railroad has 30 days to correct that condition. It should be pointed out to the 

railroad that defects must be corrected immediately (i.e., as soon as possible given the particular 

circumstances of the condition). If the condition can be corrected by making adjustments or repairs while 

making the inspection, the railroad is expected make such adjustments or repairs. If the condition cannot 

be corrected during the inspection, the railroad is obligated to initiate and complete the corrective action 

as soon as possible after the inspection. 

The inspector should use good judgment about the railroad’s obligation and ability to promptly correct the 

defective conditions cited on an inspection report. The inspector must recognize that some defective 

conditions, such as broken poles, broken crossarms, or temporary cable on top of the ground, may take 

some time and/or collection of material to correct. While such conditions are not likely to be corrected 

immediately, they should still be given high priority by the railroad. The material should be ordered 

and/or work started as soon as possible to make the repairs or replacements. 

On the other hand, the inspector should not condone the actions of a carrier that fails to promptly start 

work to correct conditions that may be accomplished immediately, such as grounded control circuits, 

defective or out of adjustment switch circuit controllers, loose switches or other components, etc. 
48 

Written Reporting of Remedial Actions Taken 

When a violation is indicated as being recommended on an inspection report, the inspector must select 

whether the railroad is required to report the remedial action, in writing, within 30 days following the end 

of the calendar month of the citation. The inspector should determine whether a remedial action is 

applicable and if so, select the box indicating that a written report of remedial action is required. When 

this is the case, the inspector must follow up to assure the remedial action is indeed reported, or a 

separate citation for the railroad’s failure to do so may be warranted (see Part 209, Subpart E, specifically 

§ 209.405). When the inspector receives the railroad’s written notification of remedial action, he or she 

shall upload the necessary information into the RISPC program. 
49 

Chapter 4 – Field Reports, Procedures, and Forms

General Requirements 

An Inspection Report Form FRA F 6180.96 shall be completed and submitted any time an inspector 

engages in inspection activity. This requirement applies to all field inspections, regardless of whether 

they are performed in connection with regular inspection activity or in connection with some special 

activity such as the investigation of an accident, complaint, block signal application or waiver request, 

false proceed signal failure, activation failure, or special assessment. All of the pertinent information 

shall be provided on the form. 

S&TC Inspections and Unit Count Guidelines 

Signal inspectors conduct inspections of wayside signal systems, automatic train stop, train control, and 

cab signal systems, and grade crossing active warning systems to determine the level of compliance 

associated with the Federal regulations applicable to those systems. Signal inspections are the backbone 

of the S&TC safety oversight program. Therefore, a high level in the quality of signal inspections is 

critical, as only a relatively small portion of the railroad’s signal and grade crossing active warning 

systems can be inspected over a period of time due to FRA’s limited resources. In order to maintain a 

high level of quality inspections, signal inspectors are, a majority of the time, to be accompanied by 

appropriate railroad personnel when conducting their inspections, with unaccompanied inspections being 

a rare exception. Appropriate railroad personnel would include those authorized to enter signal 

bungalows, instrument cases, and other similar housings, who are able to conduct the requested testing of 

the signal equipment adjustments and functionality, and who are able to establish the necessary roadway 

worker protection, as applicable. 

Generally, inspection activity related to the activity codes listed below should be conducted with some 

reasonable level of actual inspection “practice and process.” The inspection process is necessary for 

determining compliance with the various standards contained in the regulations, most notably those 

standards associated with the required functionality of the applicable systems, subsystems, or 

components. For example, whereas it is certainly possible to identify (or suspect) various safety concerns 

or even deficiencies through a cursory visual inspection (e.g., broken, loose, or missing components, or 

components not in their required location or in otherwise defective conditions, such as insulated rail 

joints, track wires, shunt wires and fouling wire connections, rail joint bonding, switch machine layout, 

and associated apparatus), a cursory visual inspection would not normally, in and of itself, constitute a 

thorough inspection. Instead, a more indepth inspection, to include an observation of various testing for 

proper functionality and required operating parameters of associated equipment, is normally desired. In 

the instance of safety concerns being visually identified prior to actually conducting specific testing, 

action should be taken to immediately notify the applicable railroad personnel and arrange for testing of 

the associated functions. If safety concerns or defective components are visually identified during an 

accompanied inspection, the associated functions of the system that could be affected must be tested or 

otherwise observed at the earliest opportunity possible in each of these scenarios, taking into 

consideration the safety risk that may be associated with the suspected condition. 

Refer to Appendix A, or the latest version of the S&TC and Multi-discipline Activity Code Table for 

further guidance regarding activity codes and unit counting. 
50 

Inspectors’ uniform use of these unit-counting criteria is necessary in that the data recorded on the FRA 

F6180.96 is entered into FRA’s electronic database and is available to generate management reports to 

determine the effectiveness of the inspection program and the degree of activity of any particular 

inspector. The information in the database can also be used to determine the degree of railroad 

compliance with FRA regulations, thus indicating which railroads are in need of more intensive signal 

inspections. 

Completion of Inspection Report Form, FRA F6180.96 

This section describes the methods to be used in preparing the FRA Form F6180.96 (Inspection Report 

Form) and the information that is required to be recorded on the form. 

The Form FRA F6180.96 is contained in the RISPC program and is designed to be used with a computer. 

It is designed so that data from the completed inspection report forms can be used for computer-aided 

storage, retrieval, sorting, and generation of reports of inspection data. 

Each inspector or regional supervisory specialist (or chief inspector) who performs a signal inspection 

shall complete and submit an FRA inspection report to the railroad when the inspection is completed. 

When a Form FRA F6180.96 is submitted that indicates a violation has been recommended, the inspector, 

regional supervisory specialist, or chief inspector is required to complete and submit a subsequent 

violation report. 

Note: The inspection report form is designed such that each line item is to indicate whether a violation is 

being recommended. Therefore, it is generally inappropriate to use more than one inspection report form 

per day to indicate a combination of deficiencies and violations, or that two or more violations are being 

recommended, even in the event different CFR parts and/or rule sections within a CFR part are being 

cited, unless it is necessary due to other information on the form (i.e., different railroad, State, division or 

subdivision, etc.) 

The S&TC Inspection Report shall be complete and understandable and shall be presented to the railroad 

representative at the end of the day’s inspection activities. If two or more inspectors are working 

together, only one FRA Inspection Report shall normally be filed and the accompanying inspector(s) 

identified in the appropriate location on the report. When the inspection activity involves an area 

regularly inspected by one of the inspectors engaged in the activity, the report shall be filed by the 

inspector who normally covers that area. 

The Inspection Report shall be filled out in accordance with the instructions found within the RISPC 

program (see “Help” file). (See Technical Bulletin G-07-03, which presents the revised source codes for 

use on the inspection report form; and Technical Bulletin S-08-01, which presents the revised S&TC 

Activity Codes.)

Note: The description block on the inspection report form is where the inspector is to describe the 

defective condition being cited. In many instances, the insertion of the defect code itself will adequately 

provide that description. However, in many other instances, especially those where a violation is 

recommended, it is highly desirable to add explanatory language as to the detail of the exception. When 
51 

clarification is necessary to a viewer of the report, the inspector shall add that minimal additional 

description of the subject condition. For example, if recommending a violation for noncompliance with 

§ 234.209, insert the defect code and add a minimal explanation of what occurred. If recommending a 

violation for noncompliance with § 236.334, insert the defect code and add a minimal explanation of the 

width of the obstruction wherein the switch was actually still indicating to be in proper position, etc. 

Distribution of Inspection Reports 

The railroad copy of the inspection report should be provided to the appropriate railroad representative 

upon the completion of each day of inspection to the extent possible. The inspector should at a minimum 

inform the railroad representative of any exceptions taken, particularly those in which a violation will be 

issued. The inspector should obtain the railroad representative’s signature on each inspection report 

provided the railroad, especially any report recommending a violation; or a receipt of acknowledgment for 

any inspection report emailed to the railroad. 

The report shall be uploaded to the data processing contractor in accordance with current instructions. 

State inspectors shall be governed by guidance from their immediate supervisors regarding the handling 

of inspection reports. 

Regional Supervisory Specialist Review of Inspection Reports 

The regional supervisory specialist shall periodically review inspection reports of each of their assigned 

inspectors for errors and/or omissions, and technical appropriateness and correctness. Each reviewed 

report shall be examined to see that all spaces are filled in with the mandatory information. 

The regional supervisory specialist shall ascertain that the rules used to cite defective conditions are 

correctly applied and that they are applicable to the system inspected, (i.e., interlocking rules cannot be 

used to cite defective conditions in automatic block signal systems). The regional supervisory specialist 

shall also review that the citations made appear to be appropriately determined to be either cited as a 

defect or a violation. Any question in either case should be discussed and resolved with the applicable 

inspector. 

Should the regional supervisory specialist find errors, omissions, or technical issues, he or she should 

immediately take steps to get a corrected copy to the data entry contractor so that the inspection data can 

be successfully entered into the database. The regional supervisory specialist should advise the inspector 

of the errors, omissions, or technical issues so that similar ones will not be made on future reports. 

The regional supervisory specialist shall also ensure that when an inspector prepares an inspection report 

recommending a violation, sufficient explanation of the condition is provided and the subsequent 

violation report is properly forthcoming. 

Completion of Violation Report Form 

Inspectors should adhere to the following instructions when writing the narrative section of the 

F 6180.112, S&TC violation report, unless otherwise instructed by their immediate supervisor or by staff 

at FRA HQ in Washington, DC.
52 

Paragraph 1. State that the carrier (full corporate name) is in violation of section XXX of the Rules, 

Standards, and Instructions Governing the Installation, Inspection, Maintenance, and Repair of Signal and 

Train Control Systems, Devices, and Appliances; or of the requirements for Grade Crossing Signal 

System Safety. Do not use abbreviations such as RS&I, HGC, etc. The violation report is an official 

document that may be used in a court of law and therefore should be as precise as possible. 

Paragraph 1a. Immediately following the first paragraph, cite the entire rule of which the carrier is in 

violation, or if it is a very long rule, cite the appropriate portion of the rule. Include the section number 

and title as a heading for the rule, and ensure that the rule is quoted correctly down to every comma and 

hyphen. When only a portion of a rule is quoted, insert a row of three dots one space apart, either in front 

of the quoted text and/or behind, to denote that a portion of the rule is intentionally not quoted. 

Paragraph 2. State the date of the inspection, when the violation was found, the name of the railroad 

representative who was accompanying the inspector (along with his or her title), and the type of system 

inspected. 

Paragraph 3. List the specific appliance or location within the system where the defective condition was 

found and a full description of the condition that prompted the violation. 

Paragraph 4. State that the condition is dangerous and explain why; or in the case of a re-inspection, 

give justification for the violation by referring to the applicable previous inspection report. List the date 

and report number of the previous inspection report and that the carrier failed to perform required 

remedial action. 

Paragraph 5. State when applicable what action the carrier took to correct the defective condition and 

when such action was taken. 

Paragraph 6. The inspector should make a recommendation for violation counts and the number of days 

for each count. 

Note: There will be occasions when an inspector files a violation report based on non-compliance with 

parts 233 or 235. Such violation reports may be revised to conform to the circumstances of the violation. 

When the F6180.112 violation report and all supportive documentation is complete, the inspector will 

forward the entire violation package to his or her supervisory specialist according to their particular 

guidance. State inspectors will be governed by the instructions from their respective States as to handling 

of the violation reports when ready for transmittal. 

Distribution of Violation Reports 

Where the inspector is recommending prosecution for a violation, the completed report along with the 

supporting documentation shall be submitted to the Regional Administrator’s office within 30 days, 

where it will be reviewed and forwarded to the Assistant Chief Counsel’s Enforcement Division. 

When the violation report is complete and ready for transmittal, an electronic Transmittal From Region 

(TFR) form shall be generated using the FRA Violation Generation, and Tracking System (VGTS) web 
53 

page on the secure site and a copy shall be attached to the violation report packet. The original and one 

copy shall then be submitted to Assistant Chief Counsel for Enforcement. One copy should also be filed 

at regional headquarters. 

State inspectors will be governed by the instructions from their respective States as to handling of the 

violation reports when ready for transmittal. 

Regional Supervisory Specialist Review of Violation Reports 

 

The regional supervisory specialist shall review each violation report for errors and/or omissions; correct 

technical terms and technical application of the regulation cited; correct format, grammar, and spelling; 

and to make sure that the information contained in the violation report provides sufficient support for the 

recommendation and that it corresponds with the information on the inspection report upon which the 

violation is based. 

After the regional supervisory specialist has reviewed the violation report and ascertained that it contains 

the necessary information and meets the criteria for a well written report, he or she will generate the 

electronic TFR form using the FRA VGTS web page on the secure site and attach a copy to the violation 

report packet. The regional supervisory specialist shall then submit the original and one copy to the 

Assistant Chief Counsel. One copy should be filed at the regional headquarters. 

The regional supervisory specialist shall return to the inspector any violation report that is improper in 

regulatory application, deficient in content, improper in format, incorrect in grammar or spelling, or where 

the information in the violation report does not support the recommendation or does not correspond with 

the information of the inspection report that recommends the violation. 

If the regional supervisory specialist does not agree with the seriousness of the condition and does not 

support the violation, he or she should discuss the issue with the inspector involved. If the inspector 

insists on recommending a violation, the regional supervisory specialist should prepare a memorandum to 

the Regional Administrator citing his or her position and the basis upon which his or her position is 

supported. The Regional Administrator will attempt to resolve the matter and in doing so, determine 

whether to forward the violation package to the Assistant Chief Counsel. If so, the regional supervisory 

specialist’s memorandum should be enclosed as cover. 

Block Signal or Waiver Application Investigation Reports 

All block signal applications (BSAP or BS-Ap) and waiver requests shall be fully investigated. When the 

application is assigned for investigation, a field investigation shall be conducted. 

The field investigation report shall be prepared on the inspector’s “Report Form for BS-Ap and RS&I-Ap 

Applications” found in the S&TC Technical Manual under Part 235. Inspectors are to follow the reportwriting examples and guidance according to the instructions contained in the Part 235 section of the 

manual. 

Regional Supervisory Specialist Review of Block Signal or Waiver Application 

Investigation Reports 
54 

The regional supervisory specialist shall review each BSAP or waiver request report for errors and/or 

omissions; correct technical terms and technical application of any associated regulations; correct format, 

grammar, and spelling; and to determine whether the recommendation made by the inspector is 

appropriate and defensible. 

The regional supervisory specialist shall return to the inspector any BSAP or waiver report that is 

improper in regulatory application, deficient in content, improper in format, incorrect in grammar or 

spelling, or where the information in the report does not correspond with the information of the railroad’s 

submission. 

After the regional supervisory specialist has reviewed the BSAP or waiver report and ascertained that it 

contains the necessary information and meets the criteria for a well written report, he or she will sign off 

on the report by indicating whether they concur in the provided location (at the end of the report). If the 

regional supervisory specialist does not concur with the inspector’s report, he or she shall prepare a cover 

memorandum to the Regional Administrator citing his or her position and the basis upon which his or her 

position is supported. The Regional Administrator or Deputy Regional Administrator shall then indicate 

their concurrence before the finished report is forwarded to the S&TC Staff Director. 

False Proceed Signal Failure Investigation Reports 

The inspector shall file a narrative report of each formal false proceed investigation. The narrative report 

should contain the following information: 

1. First paragraph: Date, time, and location of failure or alleged failure and a brief summary 

regarding the cause of the failure. 

2. Second paragraph: Type of system, technical description of the system, method of train operation, 

and maximum authorized speed. 

3. Third paragraph: Type, direction, and consist of train which observed false proceed signal failure. 

4. Fourth paragraph: Signal number, aspect displayed, device that failed, cause of failure, show how 

the failure contributed to the false proceed signal indication or hazardous condition. 

5. Fifth paragraph: What carrier action was taken and when. 

6. Sixth paragraph: What action was taken by the inspector and when. 

7. Seventh paragraph: State here when it is determined a false proceed failure did not occur. 

Use additional paragraphs for other pertinent information that may be developed. 

Attach other pertinent information that may further explain the event or the remedial action should be 

included in the report. Fully explain any event logs, event recorder printouts, or other documentation that 

is helpful in understanding the particulars of the failure. (Reference Technical Bulletin S-05-02)
55 

Regional Supervisory Specialist Review of False Proceed Signal Failure Investigation 

Reports 

The regional supervisory specialist shall review each false proceed signal failure investigation report for 

errors and/or omissions; correct technical terms and technical application of any associated regulations; 

correct format, grammar, and spelling; and to determine whether the recommendations made by the 

inspector are appropriate and defensible. 

The regional supervisory specialist shall return to the inspector any false proceed investigation report that 

is improper in regulatory application, deficient in content, improper in format, incorrect in grammar or 

spelling, or where the information in the report does not correspond with the information of the railroad’s 

submission. 

After the regional supervisory specialist has reviewed the false proceed investigation report and 

ascertained that it contains the necessary information and meets the criteria for a well-written report, he or 

she will forward the full report to the S&TC Staff Director. 

Highway-Rail Grade Crossing Activation Failure Investigation Reports 

The inspector shall file a complete report of each activation failure investigated. The report should follow 

the current instructions found in the InfoPath form for activation failures. 

There is a complete help file found on the form which provides guidance for input into each block or 

field. 

For example, the “Synopsis” field says: 

The synopsis shall include the following information: Date and time of the activation failure, 

location including city, county, state, street-road name, railroad division, railroad subdivision, 

milepost, DOT No., and a short description of the cause of the failure. 

(NOTE: This section may be released in its entirety to the FR’'s public Web site.) 

 

Other pertinent information that may further explain the event or the remedial action should be included 

in any attachments to the report. Enclose other documentation that is pertinent and helpful in 

understanding the particulars of the event. (Reference Technical Bulletin S-05-02)

Regional Supervisory Specialist Review of Highway-Rail Grade Crossing Activation 

Failure Investigation Reports 

The regional supervisory specialist shall review each activation failure investigation report for errors 

and/or omissions; correct technical terms and technical application of any associated regulations; correct 

format, grammar, and spelling; and any recommendation made by the inspector as being appropriate and 

defensible. 

The regional supervisory specialist shall return to the inspector any activation failure investigation report 

that is improper in regulatory application, deficient in content, improper in format, incorrect in grammar 
56 

or spelling, or where the information in the report does not correspond with the information of the 

railroad’s submission. 

After the regional supervisory specialist has reviewed the activation failure investigation report and 

ascertained that it contains the necessary information and meets the criteria for a well-written report, he or 

she will forward the full report to the S&TC Staff Director. 

National Safety Program Plan (NSPP) Status Reports 

An NSPP is developed by both the S&TC Staff Director for national or multiregional scope, and by each 

respective region as it deems necessary. Each project identified is expected to be accompanied by a status 

report at the end of each quarter, and a final report is due at the end of the fiscal year. Each region, as is 

applicable, is to forward to the S&TC Staff Director the information required in order for him or her to 

complete the status reports of HQ projects that involved the region’s efforts. 

Other Special Project Reports 

Any time a special project, assessment, team or focused effort is conducted, the expectation is that a 

resulting report will be prepared regarding the issues identified, actions taken, findings, and the results or 

outcome. This report may be regional, multiregional, or national in scope. The report should be provided 

to the originator of the project, but at least one copy should be provided to the appropriate S&TC HQ 

staff. 
Appendix  A

Activity Code Tables
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

174A H, M General Requirements – The purpose of this inspection is to determine compliance with §§174.3, 

174.5, 174.9, 174.14, 174.16 and 174.50. This code is to be used for railroad facility inspections. 

Record one unit for the inspection of each car transporting hazardous materials. 

174B H, O General Operating Requirements – The purpose of this inspection is to review a train crew’s 

documentation for each railcar containing hazardous material, including any changes in placement of 

the car. The inspection should include determining compliance with the basic hazardous materials 

shipping paper descriptions as required in §174.26. Record one unit for each train consist inspected, 

and one subunit for each inspection of the basic shipping paper description of each car containing 

hazardous materials. 

Note 1: Inspectors must use activity code TPLH to record inspections associated with train placement 

requirements. 

Note 2: Inspectors must use this code instead of code 172C when inspecting shipping papers specific to 

a particular train. 

209 ALL Remedial Action – The purpose of this inspection is to report a railroad that has not complied with a 

requirement to provide a remedial action as noted in a previous inspection report. Record one unit for 

each remedial action not in compliance. (See General Manual for additional guidance).

215D H, O, S, T Freight Car Mechanical Inspection – The purpose of this inspection is for any inspector other than 

an MPE inspector to determine compliance with § 215, including Appendix D. The inspection 

includes those performed by an FRA inspector or when an FRA inspector observes railroad employees 

performing this inspection. MPE inspectors should reference activity code 215. Record one unit for 

each freight car inspected or observed inspected for compliance with §215. For articulated cars, count 

each platform as one unit. 

 

Note 1: HM and OP inspectors should use this activity code HM for ALL of their Part 215 inspections. 

Note 2: Properly stenciled Maintenance-of-way equipment is exempt from Part 215.305(b).

217E ALL Emergency Order – The purpose of this inspection is to determine compliance with a current 

Emergency Order. Record each unit and subunit as directed by the unique instructions issued by FRA 

HQ regarding each specific Emergency Order. Inspectors must thoroughly explain the inspection in the 

inspection report’s narrative. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

217O ALL Other Operations Observations - The purpose of this inspection is to observe railroad employees of 

any craft performing duties regarding railroad operating rules (ROR), and railroad safety rules(RSR). It 

will include all related RORs, RSRs, railroad bulletins, and any written railroad policy not otherwise 

covered in Federal regulations. Noncompliance will be recorded as a Non-FRA defect under this 

activity code. Record one unit for an entire yard or equivalent facility monitored, and one subunit for 

each crewmember, yardmaster, contractor, track employee, mechanical employee, signal maintainer, 

etc, that the inspector continually observed a sufficient amount of time to determine compliance or 

noncompliance. 

Note: Unlike noncompliance with Federal regulations, it is FRA policy that inspectors provide 

information recorded under this activity code regarding noncompliance of an ROR/RSR without 

identifying the noncompliant employee by name in the Federal inspection report. See the General 

Manual for a further explanation. 

Example 1: An FRA Track Inspector observes a 20 person section gang working for approximately 45 

minutes when the inspector observes a track employee sitting on the rail. The FRA inspector intervenes 

by addressing the employee’s noncompliance with an RSR, and then discusses the noncompliance with 

the employee’s supervisor. The inspection report will include the recording of one occurrence of a NonFRA defect for a track employee’s failure to comply with the specific RSR that prohibits employees 

from sitting on a rail. The inspector will record the inspection as one unit and 20 subunits 

Example 2: An FRA MPE Inspector observes four persons working on a railroad car with proper Blue 

Signal protection for approximately 10 minutes when the inspector observes one of the workers perform 

a task while not wearing the required protective equipment. The FRA inspector intervenes by 

addressing the employee’s noncompliance with a RSR by discussing it with the employee’s supervisor. 

The inspection report will include the recording of a Non-FRA defect for a car shop employee’s failure 

to comply with the specific RSR that prohibits performing the task without the proper protective 

equipment. The inspector will record the inspection as one unit and four subunits. 

218C O,S,T Camp Car Protection - The purpose of this inspection is to determine compliance with camp car 

protection. Record one unit for each track inspected that requires camp car protection. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

218M M, O Blue Signal Protection on Main or Other than Main Track - The purpose of this inspection is to 

determine if the protection provided railroad employees requiring Blue Signal protection in accordance 

with §§ 218.25, 218.27, and 218.30. Record one unit for each track that requires Blue Signal 

protection. If the track requiring Blue Signal protection has more than one train or cut of cars requiring 

protection record one unit for the entire track. 

Regarding inspecting compliance with Blue Signal regulations involving a remotely controlled switch. 

Record one unit for all associated recordkeeping requirements at that location, and one subunit for each 

track associated with those records. 

Note 1: Except for stub tracks, both ends of the track must be inspected for compliance with the Blue 

Signal regulations. 

Note 2: There is a drop-down FRA observation code inspectors may use in lieu of writing a comment 

when there are not any exceptions noted. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

1

Activity 

Code 

Discipline Definition 

211 S Hours of Service – One unit for each signal employee who exceeded the hours of service. DO 

NOT use this Activity Code for Part 228 Hours of Duty Recordkeeping, as it has its own activity 

code. 

Note: When using this activity code, the inspector must have a companion 228 code on the 

same report. If the activity results in a civil penalty recommendation against the railroad, any 

companion 228 code civil penalty recommendations found during the same inspection must be 

referenced on the same inspection report. If there is a discrepancy between the hours of service 

record and the alleged exceeding the hours of service it must be explained in the report. If 

additional 228 defects are found during a subsequent inspection for the same case of excess 

service (railroad’s excess service report, for example), the initial inspection report number must 

be referenced. 

ABSO S Automatic Block System Other - One unit for inspection and testing of each timing relay or 

timing device, and each auxiliary component within and interconnected to an Automatic Block 

System such as: slide protection devices, flood detectors, dragging equipment detectors, wide 

load detectors, hot bearing detectors, etc., or other similar devices affecting the control of the 

signal system. 

ABSS S Automatic Block System Signals - One unit for inspection of each signal and all basic 

components associated within the control of a signal, such as: the track circuits and track wire 

connections, insulated rail joints, signal control relays or processor-based control equipment, 

line circuits, circuit plans, and relay or processor-based equipment housings. 

Note: Count one unit for each complete signal as would be viewed from the approaching 

direction, regardless of the number of signal heads on the signal (i.e., a red, over red, over lunar 

would count as one unit; a yellow over red as one unit; etc. A back-to-back signal, regardless of 

the number of signal heads on each, would be counted as two units.) 

ABSW S Automatic Block System Switches - One unit for inspection of each switch, switch-and-lock 

movement, pipeline-connected lock, facing point lock of a mechanically locked switch, switch 

circuit controller, independently protected (circuited) derail, electric lock of a hand-operated 

switch, and any associated insulated rail joints, fouling circuits, pipe-connected derail, etc. 

within a switch layout. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

2

Activity 

Code 

Discipline Definition 

ACSL S Automatic Cab Signal Locomotive - One unit for each inspection of automatic cab signal 

(ACS) equipment, including the cab signal display, control equipment, audible alarm, cut-out 

device(s), and associated housings and wiring; and inspection and testing of each timing relay or 

timing device, that is installed on a diesel-electric locomotive unit, electric unit, or multiple-unit 

car. 

ACSO S Automatic Cab Signal Other - One unit for inspection of each ACS test loop, cut section, 

and/or other location where testing of control circuitry occurs; and for inspection and testing of 

each wayside timing relay or timing device associated with such ACS system. 

ATCL S Automatic Train Control Locomotive - One unit for each inspection of automatic train control 

(ATC) equipment, including the cab signal display, control equipment, audible alarm, cut-out 

device(s), and associated housings and wiring; and inspection and testing of each timing relay or 

timing device, that is installed on a diesel-electric locomotive unit, electric unit, or multiple-unit 

car. 

ATCO S Automatic Train Control Other - One unit for inspection of each ATC test loop, cut section, 

and/or other location where testing of ATC control circuitry occurs. 

ATSL S Automatic Train Stop Locomotive - One unit for each inspection of automatic train stop 

(ATS) equipment, including the cab signal display, control equipment, audible alarm, cut-out 

device(s), and associated housings and wiring; and inspection and testing of each timing relay or 

timing device, that is installed on a diesel-electric locomotive unit, electric unit, or multiple-unit 

car. 

ATSO S Automatic Train Stop Other – One unit for inspection of each ATS inductor, ATS 

acknowledgment loop, or other location where associated testing of ATS control circuitry 

occurs. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

3

Activity 

Code 

Discipline Definition 

HGCO S Highway-rail Grade Crossing Other - One unit for inspection and testing of any device 

associated with the HGCS installation which is not covered under activity code HGCS or other 

appropriate code. Examples: Special wayside indicators used to inform trains of the warning 

system status, special interconnected systems which utilize traffic signals in lieu of flashing 

lights, and etc. 

Note 1: This activity code should not be used for inspection and testing of switch cut-out 

circuitry associated with HGCS. Use of the HGCW code will include inspection and testing of 

any applicable switch cut-out device or reverse switch cut-out arrangements associated with 

highway-rail grade crossing warning systems. 

HGCR S Highway-rail Grade Crossing Record - One unit for each day, or partial day, for inspection of 

records regarding the results of tests and/or inspections performed in the office of a supervisory 

official having jurisdiction. 

 

Note: Record one subunit for each record inspected, i.e., each single form, card, page, or sheet, 

or comparable electronic record, filed or, in the case of electronic record, accessed or obtained, 

in an appropriate manner and from an official source. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

HGCS S Highway-rail Grade Crossing Signal – Inspectors must record one unit for inspection of an 

entire highway-rail grade crossing warning system installation. Examples of an entire 

installation include: flashing lights with bell, flashing lights with gates and bells, wigwag, and 

etc. This single activity code count shall include related components such as the main 

equipment housing, circuit plans, relay or electronic control equipment, standby battery or power 

source, battery chargers, signs mounted on crossing signal masts, associated pole line, aerial 

cable, underground cable, and etc. 

Note: In addition to the one unit for each installation covered by the HGCS activity code, 

inspectors should record one subunit for inspection or testing of certain sub-components related 

to the HGC or pathway crossing warning system, as listed below. 

 One subunit for flashing lights mounted on a mast (one subunit for each pair of flashing 

lights or in those rare cases where a single flashing light is used, by design, for an 

approaching lane of traffic.) 

 One subunit for flashing lights mounted on a cantilever (one subunit for each pair of 

flashing lights or in those rare cases where a single flashing light is used, by design, for 

an approaching lane of traffic) 

 One subunit for each strobe light, variable message sign, or other special lighting 

arrangement used in lieu of flashing lights, and etc. 

 One subunit for each gate mechanism including associated gate arm and gate lights 

 One subunit for each train detection circuit, including all track wire connections, rail 

joint bonding, and insulated rail joints 

 One subunit for each audible warning device (e.g., bell) 

 One subunit for each timing relay and/or timing device 

 One subunit for each cut-out device such as, push-button or key-operated devices 

associated with the system 

 One subunit for each highway traffic signal interconnect circuit, traffic signal preemption equipment and circuitry 

 One subunit for any additional approved component(s) not listed above 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

HGCW S Highway-rail Grade Crossing Switch - One unit for inspection of each power, or handoperated switch if the switch points or a derail is equipped with a cut-out feature, and/or is 

interconnected with HGCS control circuits. The insulated rail joints, any fouling circuits, 

fouling wires and connections, rail joint bonding in the switch layout, switch cut-out circuitry, 

and any associated pipe-connected derail, shall all be considered as part of the switch. 

Note: If a switch is being inspected for proper functioning of its interconnection with an HGCS 

System, use this activity code. If the switch is also being inspected for proper functioning as 

part of a signal system, use the appropriate activity code which matches the signal system, e.g. 

ABSW, TCSW, INTW and etc. It is possible in certain locations that inspectors may inspect the 

same switch as part of an HGCS system as well as another signal system, which will require the 

use of both activity codes, as applicable. 

IMBO S Interlocking – Movable Bridge Other - One unit for each signal interlocked movable bridge 

when additional testing and inspection is performed beyond what is listed under IMBS. 

If movable bridge interlocking is equipped with one or more of the following, count one subunit 

for inspection and/or testing of each: 

 Time locking circuit 

 Approach locking circuit 

 Route locking circuit 

 Indication locking circuit 

 Timing relay or timing device 

 Traffic locking circuit (if equipped) 

 Mechanical locking device, including mechanical locking of an interlocking machine 

 Associated boat or water traffic sensors or lights 

 Associated bridge position sensors 

 Associated audible warning or announcement (e.g. horns, sirens, and etc.) 

Note: Example - Inspector observed testing of 2 time locking tests and 3 timing relay tests. Unit 

count would be 1 Unit under IMBO, and 5 subunits under IMBO. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

IMBS S Interlocking – Movable Bridge Signal - One unit for inspection of each signal governing 

movements into and through an interlocking associated with a movable bridge, and everything 

associated within the control of the signal, such as: the track circuits and track wire connections, 

loss-of-shunt circuits, insulated rail joints, ground test of each energy buss, signal control relays 

or processor-based control equipment, line circuits, cable circuits, and circuit plans. 

Count one subunit for each test and/or inspection of the following: 

 Circuit controller or other detection device used in place of a circuit controller involved 

in detecting surface or alignment of movable rails 

 Circuit controller or other detection device used in place of a circuit controller involved 

in detecting bridge locking 

 Circuit controller or other detection device used in place of a circuit controller involved 

in detecting bridge seating 

 Circuit controller or other detection device used in place of a circuit controller involved 

in detecting rail locks or any other function which is part of the bridge interlocking 

 Switch machine that powers pipe lines, rail locks, easer bars, lift rails, Conley frogs, or 

any associated device other than a switch or derail 

 Pushbutton and/or emergency release device 

 

Example: Inspection of bridge with single track main would usually have a signal for each 

direction of rail traffic. The count would be 2 IMBS units, with the corresponding number of 

subunits, depending on which subunit items receive inspection. 

Note 1: Count one unit for each complete signal as would be viewed from the approaching 

direction, regardless of the number of signal heads on the signal (i.e., a red, over red, over lunar 

would count as one unit; a yellow over red as one unit; etc.). 

Note 2: Each switch or derail within limits of bridge interlocking should be counted as IMBW, 

following the instructions under IMBW activity code section. Locking circuit tests, timing 

relays, and other extra tests and inspections should be listed under IMBO as per the instructions. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

IMBW S Interlocking – Movable Bridge Switch - When switch or derail is within bridge interlocking 

limits, count one unit for inspection of each single switch, each power-operated derail, each set 

of movable-point frogs, each single-slip switch, and each double-slip switch. Everything in the 

operation or control of a switch or derail, such as the switch-and-lock movement, pipeline, 

facing point lock of a mechanically-locked switch, and switch circuit controller; and an electric 

lock of a hand-operated switch will be considered as a part of the switch. The insulated rail 

joints, any fouling circuits, fouling wires and connections, rail joint bonding in the switch layout, 

and any associated pipe-connected derail shall all be considered as part of the switch. 

INTO S Interlocking Other - One unit for inspection and testing of each traffic locking circuit, time 

locking circuit, approach locking circuit, route locking circuit, indication locking circuit, loss-ofshunt circuit, each timing relay or timing device, mechanical locking of an interlocking 

machine, or pushbutton and emergency release devices. 

INTS S Interlocking Signal - One unit for inspection of each signal governing movements into and 

through an interlocking, and everything associated within the control of the signal, such as: the 

track circuits and track wire connections, insulated rail joints, signal control relays or processorbased control equipment, line circuits, and relay or electronic equipment housings. 

Note: Count one unit for each complete signal as would be viewed from the approaching 

direction, regardless of the number of signal heads on the signal (i.e., a red, over red, over lunar 

would count as one unit; a yellow over red as one unit; etc.) 

INTW S Interlocking Switch - One unit for inspection of each single switch, each power-operated derail, 

each set of movable-point frogs, each single-slip switch, and each double-slip switch. 

Everything in the operation or control of a switch or derail, such as the switch-and-lock 

movement, pipeline, facing point lock of a mechanically-locked switch, and switch circuit 

controller; and an electric lock of a hand-operated switch will be considered as a part of the 

switch. The insulated rail joints, any fouling circuits, fouling wires and connections, rail joint 

bonding in the switch layout, and any associated pipe-connected derail shall all be considered as 

part of the switch. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

LCSR S Locomotive Control System Record - One unit for each day, or partial day, for inspection of 

records regarding the results of tests and/or inspections performed in the office of a supervisory 

official having jurisdiction, or obtained in an appropriate manner and from an official source. 

Note 1: Record one subunit for each record inspected, i.e., each single form, card, page, or sheet, 

or comparable electronic record, filed or, in the case of electronic record, accessed, or obtained 

in an appropriate manner and from an official source. 

Note 2: When inspecting records maintained onboard an equipped locomotive (e.g. departure 

test, daily or after-trip test, etc.) count one LCSR unit per locomotive where records are 

inspected, and one subunit for each specific record reviewed for compliance. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

LTS S Life Tips STC – Record one unit for each interaction/briefing of railroad or contractor 

employees regarding Federal regulations or issues regarding railroad safety. Record one subunit 

for each member of the work group. When using this code, the inspector must write a brief 

description (two sentences or so) in the “Comments” section of the inspection report (F6180.96). 

Example 1: You attend a safety meeting to discuss railroad safety issues (RWP, 218 Subpart F, 

and etc.). This meeting consisted of one signal supervisor and two signal maintainers. Record 

this activity as one unit under LTS, and three subunits under LTS. 

Example 2: You have active involvement in a job safety briefing with a train crew, group of 

roadway workers, etc. Your involvement may include FRA regulations regarding personal or 

operational safety (Parts 214, 218, etc.) Record this activity as one unit under LTS, and record 

one subunit for each train crew member, work crew member, etc. 

Example 3: You have active involvement in a discussion with five railroad workers regarding 

an FRA Safety or Emergency Advisory. Record this activity as one unit and five subunits under 

LTS. 

Note 1: This activity code does not include an FRA inspector debriefing a railroad 

representative(s) in connection with an FRA inspection report (F6180.96). 

Note 2: This activity code does not include attending a labor organization’s meeting. 

OTHL S Other System Locomotive - One unit is recorded for each locomotive inspected for onboard 

equipment, which is not covered by activity codes ACSL, ATCL, or ATSL. 

OTHO S Other System Other – One unit for inspection of each supplementary device or function within 

an "other signal arrangement" (similar to a type of signal system). Examples could include: 

track integrity warning system, remote switch control or switch position detection system, 

locomotive pacing or speed control system, unusual contingency detection system, etc., all 

within an otherwise non-signaled territory. 

OTHS S Other System Signal – One unit for inspection of each indicating device or method of 

providing route information (e.g., audio broadcast) in an “other signal arrangement” or system. 

Also includes supplementary devices or functions within an “other signal arrangement.” 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

OTHW S Other System Switch - One unit for inspection of each single switch, each power-operated 

derail, each set of movable-point frogs, each single-slip switch, and each double-slip switch in 

an "other signal arrangement" type of system, all within an otherwise non-signaled territory. 

Everything in the operation or control of a switch or derail, such as the switch-and-lock 

movement, associated pipeline, facing point lock of a mechanically-locked switch, and switch 

circuit controller; an electric lock of a hand-operated switch will be considered as a part of the 

switch. The insulated rail joints, any fouling circuits, fouling wires and connections, rail joint 

bonding in the switch layout, and any associated pipe-connected derail shall all be considered as 

part of the switch. 

PTCC S Positive Train Control Communications - One unit for inspection of any of the 

communications portion of a Positive Train Control (PTC) system that develops, executes, 

transmits, receives, or stores any safety-critical data, to or from one location to another, for 

which its proper function is relied upon in the expected performance of the system. 

PTCD S Positive Train Control - Dispatching or Control Center - One unit for inspection of any part 

of the office portion of a PTC system that is used to develop, execute, transmit, receive, or store 

any safety-critical data, for which its proper function is relied upon in the expected performance 

of the system. 

PTCG S Positive Train Control Geographic Information System - (GIS, includes Track Database) 

One unit for inspection of any of the GIS information portion of a PTC system that is used to 

develop, execute, transmit, receive, or store any safety-critical data, for which its proper 

function is relied upon in the expected performance of the system. 

PTCI S Positive Train Control – Incident Investigation - One unit for an “activity” directly associated 

with the informal investigation of any incident associated with any safety-critical function of a 

PTC system where an inspection report is not otherwise warranted. (This would not include a 

formal accident or complaint investigation as an inspection report would be warranted using the 

other applicable activity codes which would apply in such a case.) 

PTCL S Positive Train Control Locomotive - One unit for inspection of the equipment and/or 

functionality onboard any PTC-equipped locomotive that is associated with the proper and 

intended performance of the system. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

PTCM S Positive Train Control Monitor - One unit for accompanying and observing any type PTC 

system testing that would not be captured in one or more of the other existing PTC codes. This 

code is reserved for use in activities prior to revenue service of a PTC system. Examples would 

include: track database verification, wayside interface unit verification, train braking testing, 

back office testing, locomotive onboard installations, communication coverage testing, etc. 

Note: Use this code for pre-revenue service test monitor activity such as track database 

verification, train brake or stopping distance testing, and etc.

PTCO S Positive Train Control Other - One unit for inspection of the equipment and/or functionality of 

any PTC subsystem or component that is associated with the proper and intended performance 

of the system and is not better identified or included in any other PTC activity code.

PTCP S Positive Train Control Plans - One unit for inspection of a Railroad Safety Program Plan or 

Product Safety Plan and any associated documentation such as: the Operations and Maintenance 

Manual, training programs, configuration management plans, hazard tables and documents, etc. 

PTCR S Positive Train Control Record - One unit for inspection each day, or partial day, of the records 

associated with the proper and intended performance of a PTC system, such as: inspection or 

test records, training records, failure records, hazard logs, and etc. 

Note: Record one subunit for each record inspected, i.e., each single form, card, page, or sheet, 

or comparable electronic record, filed or, in the case of electronic record, accessed, or obtained 

in an appropriate manner and from an official source. 

PTCS S Positive Train Control Signal - One unit for inspection of any signal, other similar indicating 

device, or other method of providing route information associated with the proper and intended 

performance of a PTC system that is not already identified or included in any other activity code 

associated with an underlying conventional signal system or other signal arrangement (e.g., 

ABSS, TCSS, OTHS etc.).

PTCT S Positive Train Control Trackside Equipment - (includes Wayside Interface Unit –WIU). One 

unit for inspection of any trackside equipment associated with the proper and intended 

performance of a PTC system that is not already identified or included in any other activity code 

associated with a conventional signal system or other similar arrangement or system. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

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Activity 

Code 

Discipline Definition 

PTCW S Positive Train Control Switch - One unit for inspection of any monitored switch associated 

with the proper and intended performance of a PTC system that is not already identified or 

included in any other activity code associated with an underlying conventional signal system or 

other similar arrangement or system (e.g., ABSW, TCSW, OTHS, etc.).

SIGO S Signal Other - One unit for inspection or investigation of any matters concerning Part 236, 

Subpart H or I requirements, not otherwise captured within any of the other S&TC activity 

codes, including PTC. An example would be a new or novel processor-based dispatching 

system through which train movements or track occupancy authorities, or other safety-relevant 

information, are electronically generated and delivered without dispatcher or control operator 

concurrence or confirmation. 

SIGR S Signal Record - One unit for each day, or partial day, for inspection of records regarding the 

results of tests and/or inspections performed in the office of a supervisory official having 

jurisdiction or obtained in an appropriate manner and from an official source, which are not 

captured by another specific activity code. 

Note: Record one subunit for each record inspected, i.e., each single form, card, page, or sheet, 

or comparable electronic record, filed or, in the case of electronic record, accessed, or obtained 

in an appropriate manner and from an official source. 

SMCP S Software Management Control Plan - One unit for each location where inspector reviews or 

inspects a railroad's software management control plan (SMCP), the status of implementation of 

the plan, railroad compliance with the prescribed process and procedures of the plan, and etc. 

Note: Record one subunit for each specific software line item listed on the railroads SMCP 

inventory which is inspected or verified for compliance. 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

13

Activity 

Code 

Discipline Definition 

STRM S Signal Train Ride - One unit for conducting an inspection from onboard the locomotive of a 

train, including visual inspection of obvious conditions and/or functions of a signal system or 

other signal arrangement. A train ride warrants one STRM unit for each specific train, i.e., if 

riding on one train in one direction and another train back; or one train for a distance and then 

another train further in the same direction; record one unit for each of the two different trains in 

each case. 

Note 1: Record one subunit for each mile traveled during the onboard inspection. 

 

Note 2: Most defective conditions which may be observed from the train, such as those related 

to pole lines or highway-rail grade crossing warning systems should be shown on the inspection 

report as "Comments to The Railroad." If however an inspector observes any condition of an 

imminent safety concern (such as an observed activation failure), the train crew should 

be requested to immediately report the condition to the designated person(s). The other activity 

codes and unit counts associated with onsite inspection of the individual locations along the 

route of the train ride should not be listed on the report. This inspection data is only 

appropriate when separate specific onsite inspections are performed. 

TCSO S Traffic Control System Other - One unit for inspection and testing of each time locking 

circuit, approach locking circuit, route locking circuit, indication locking circuit, loss-of-shunt 

circuit, each timing relay or timing device; or slide protection device, dragging equipment 

detector, wide load detector, hot bearing detector, or flood detector, and etc., interconnected with 

the signal system at each location. 

TCSS S Traffic Control System Signal - One unit for inspection of each signal and everything 

associated within the control of a signal, such as: track circuits and track wire connections, 

insulated rail joints, signal control relays or electronic equipment, line circuits, circuit plans, and 

relay or electronic equipment housings. 

Note: Record one unit for each complete signal as would be viewed from the approaching 

direction, regardless of the number of signal heads on the signal (i.e., a red, over red, over lunar 

would count as one unit; a yellow over red as one unit; etc. A back-to-back signal, regardless of 

the number of signal heads on each, would be counted as two units.) 
Signal & Train Control Activity Code Table of Definitions 

April 3, 2012 

14

Activity 

Code 

Discipline Definition 

TCSW S Traffic Control System Switch - One unit for inspection of each single switch, each poweroperated derail, each set of movable-point frogs, each single-slip switch, and each double-slip 

switch. Everything in the operation or control of a switch or derail, such as the switch-and-lock 

movement, associated pipeline, facing point lock of a mechanically-locked switch, and switch 

circuit controller and electric lock of a hand-operated switch, will be considered as a part of the 

switch. The insulated rail joints, any fouling circuits, fouling wires, associated rail joint bonding 

in the switch layout, and any associated pipe-connected derail shall all be considered as part of 

the switch. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

218O ALL Part 218 Subpart F – The purpose of this inspection is to determine a railroad’s compliance with Part 

218 Subpart F, including the requirement for a railroad to have complying railroad operating rules as 

indicated in the regulation. Record one unit for each day, or partial day, spent reviewing relevant 

railroad rules or for each yard or equivalent facility monitored. Record one subunit for each 

crewmember, yardmaster, contractor, track employee, mechanical employee, signal maintainer, etc, that 

the inspector continually observed a sufficient amount of time to determine compliance or 

noncompliance. 

Note: It is FRA policy that inspectors provide information regarding incidents recorded under this 

activity code as noncompliance of a Federal regulation. It will include identifying the noncompliant 

individual by name in the inspection report. See the General Manual for a further explanation. 

Example 1: An FRA Track Inspector observes a 12 person section gang working for approximately 45 

minutes when the inspector observes a track employee throwing a switch with equipment in the foul of 

the switch. The FRA inspector intervenes by addressing the employee’s noncompliance with §218 

Subpart F, and then discusses the noncompliance with the employee’s supervisor. The inspection report 

will include the recording of the noncompliance for the track employee’s failure to comply with Part 

218 Subpart F, and the name of the employee in noncompliance. The inspector will record the 

inspection as one unit and 12 subunits. 

Example 2: An FRA MPE Inspector observes six persons switching railcars in a car shop for 

approximately 10 minutes when the inspector observes one of the workers fail to properly protect a 

shoving movement. The FRA inspector intervenes by addressing the employee’s noncompliance with 

§218 Subpart F, and then discusses the noncompliance with the employee’s supervisor. The inspection 

report will include the recording of the noncompliance for the car shop employee’s failure to comply 

with the Part 218 Subpart F, and the name of the employee in noncompliance. The inspector will 

record the inspection as one unit and six subunits. 

Example 3: An inspector reviews the railroad rules to determine if they are in compliance with the 

requirements setforth regarding railroad equipment in the foul and operating switches. The inspection 

report will include the recording of one unit for this inspection and will also reference the precise 

railroad rule(s), or lack thereof, in the inspection report’s narrative. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

218S M, O Blue Signal Protection Locomotive or Car Shops - The purpose of this inspection is to determine 

compliance with regulations requiring Blue Signal protection in a locomotive servicing track area, a car 

shop repair track area, or a track that has been designated as a repair track or expedite track. Record one 

unit for each area inspected. 

If § 218.29(c), Alternative methods of protection, applied in a car shop repair track area or a locomotive 

servicing track area, one unit is recorded for the entire area, regardless of the number of tracks in the 

area or the number of cars or locomotives on those tracks. 

Note 1: Except for stub tracks, both ends of the track, or each entrance to the area must be inspected for 

compliance with the regulation. Workers must be on, under, or between equipment, inspecting, testing 

repairing, or servicing before recording a unit for this activity. 

Note 2: There is a drop-down FRA observation code inspectors may use in lieu of writing a comment 

when there are not any exceptions noted. 

221 M, O Rear End Markers – The purpose of this inspection is to monitor compliance with Part 221. This 

activity code should not be used when inspecting an End of Train (EOT) device under Part 232. 

Record one unit for each train, locomotive (including DPU’s) or caboose inspected for compliance. 

The inspection of each rear end marking device in rooms or locations where rear end marking devices 

are stored and/or recharged and maintained is one unit. Each rear end marker ID must be recorded in 

the line item along with the appropriate observation. Individual marking devices that are not attached to 

trains or in storage areas not subject to service are not recorded as a unit. 

Note: There is a drop-down FRA observation code inspectors may use in lieu of writing a comment 

when there are not any exceptions noted. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

227N IH 227N - Occupational Noise Exposure - The purpose of this inspection is to determine compliance with 

Part 227 regarding occupational noise exposure in the locomotive cab. It will include audiometric test 

records, employee noise exposure monitoring plan and monitoring records, cab noise monitoring 

records, postings of monitoring results, training plans and records, or interviewing persons regarding 

noise exposure. Record one unit for each day or partial day of an inspection and one subunit for each 

Part 227 record reviewed. 

Note: This activity may only be claimed when accompanied by a member of the Industrial Hygiene 

staff. 

228 O, S Hours of Service Records Inspection – The purpose of this inspection is to determine if Hours of 

Service (HOS) records are in compliance with Part 228. Record one unit for each day or partial day of 

inspection, and one subunit for each HOS record reviewed. This activity code includes any examination 

of HOS logs, HOS report forms, HOS documents, interviewing employees regarding HOS, and any 

other HOS records review activity. This activity code is not used to document an employee exceeding 

the HOS. 

Note: Reports taking exception to an employee exceeding the hours of service should not be recorded 

under this activity code, please reference the proper activity code associated with the employee’s type of 

work or discipline. Example: Activity Code 228P, 211, or HSL. 

228C O,S Construction of Employee Sleeping Quarters – The purpose of this inspection is to determine 

compliance with Part 228 Subpart C. Record one unit for each day, or partial day, spent reviewing 

relevant facilities regarding Part 228 Subpart C. 

229X H, O Locomotive Inspection in Operations – The purpose of this inspection is for any inspector, other than 

an MP&E inspector, to determine a railroad’s compliance with Part 229. Record one unit for any 

locomotive inspected. The inspection may include, but is not limited to, the locomotive daily 

inspection, any passageway tripping hazards, cab sanitation, cab lighting, speed indicator check, etc. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

232E M, O End of Train Device – The purpose of this inspection is to inspect an End of Train (EOT) device for 

compliance of §232. The inspection must include verifying that the information on the calibration 

sticker is legible, and that it contains the date, name of person, and location of the last calibration. This 

activity also includes comparing the quantitative values between the front and rear unit, and the ability 

of the rear unit to effect an emergency application in response to an emergency application initiated 

from the front unit. Record one unit for each EOT inspected or observed for compliance. 

Note: This activity code will be used when citing defects on the Head End Device (HED) associated 

with the End of Train device (EOT). 

232O H, O, S, T Freight Train Brake Test Observation – The purpose of this inspection is for any inspector, other 

than an MP&E inspector, to determine compliance with Part 232 not covered in activity code 232E or 

232X. It includes any airbrake test required by Part 232. Airbrake test inspections should include in the 

narrative of the inspection report if the inspector was observing or accompanying a railroad employee or 

contractor employee performing the airbrake test. Record one unit for each observation or inspection, 

and one subunit for each railcar involved. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

232X M, O Securement of Locomotive and Cars – The purpose of this inspection is to determine if railroad 

equipment is in compliance with §232.103 (n). Record units as follows: 

1. Record one unit for an inspection of unattended equipment that consists of a single locomotive 

or locomotive consist, either attached to cars or not. This inspection includes determining 

compliance with the requirements for throttle position, status of the reverse lever, position of the 

generator field switch, status of the independent brakes, position of the isolation switch, 

handbrake, and position of the automatic brake valve. 

2. Record one unit for an inspection of unattended equipment NOT attached to locomotives that 

are required to be secured under this regulation. This unit includes inspections for bottled air. . 

Note 1: If a train is separated to avoid blocking any type of crossing it should have each section of the 

equipment recorded as a separate unit. 

 

Note 2: The inspection report that records a defect or recommended violation indentified should clearly 

state the number of handbrakes found to be applied, the number of handbrakes required to be applied, 

and the current operating rule in place that indicates the precise number of handbrakes required to be 

applied. 

Note 3: This inspection also includes an inspector reviewing railroad rules for compliance of this part. 

Example: If 30 unattended railcars are found on a track that is required to have seven hand brakes 

applied but the inspection reveals that only has one handbrake is applied, it will be recorded as one unit 

with one occurrence for the failure to have the other six handbrakes applied. 

238O H,O, S, T Passenger Equipment Inspection (Partial) – The purpose of this inspection is for any inspector, 

other than an MP&E inspector, to determine compliance with Part 238 that is not covered in activity 

codes 232X or 238T. Record one unit for each inspection and a subunit for each passenger car 

inspected. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

238T M, O Passenger Train Brake Test Observation – The purpose of this inspection is to document an 

observation of a passenger train airbrake test, excluding tourist equipment. Record one unit for each 

entire brake test observed for compliance with §238, and one subunit for each railroad record associated 

with the Class I airbrake test. 

Note: There is a drop-down FRA observation code inspectors may use in lieu of writing a comment 

when there are not any exceptions noted. 

238X M, O Passenger Equipment Securement – The purpose of this inspection is to determine if passenger or 

commuter equipment is properly secured (excluding tourist equipment). Record one unit for each train, 

whether or not a locomotive is attached. 

BPL H, M Bulk Packages, (Applies to bulk packagings, including Intermodal Portable Tanks and 

Intermediate Bulk Containers, other than tank cars) – One unit for each limited, ground level 

inspection of both sides of the bulk package and does not include a top level inspection. This activity 

code may only be used when assessing compliance with §§172.302, 172.304, 173.326, 172.502, 

172.516, and 174.50. 

Note 1: Use TCL & TCT codes to record tank car inspections. 

BWS S,T Bridge Worker Safety – An inspection concerning Part 214 Subpart B, Bridge Worker Safety 

Standards. Record one unit for each bridge gang or work group, and one subunit for each member of 

the gang or work group. 

FCL H, M Inspection of Freight Containers, General Handling and Loading Requirements – The purpose of 

the inspection includes inspecting the exterior of freight containers for markings, placards, structural 

integrity, and securement to the railcar. Record one unit for each freight container inspected. 

Note 1: Use BPL & BPT codes to record intermodal tank inspections.
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

NOIR ALL Noise Test Records – The purpose of this inspection is to document a review of a locomotive’s noise 

testing session, or a locomotive’s noise testing record. Record one unit for each locomotive’s noise 

testing session monitored and/or all noise testing records associated with the locomotive tested. 

 

Example 1: A short line railroad has three records on file documenting a locomotive horn test 

performed on locomotive SP 1234. Record one unit for the examination of all three records. 

Example 2: A short line railroad has three records on file documenting a locomotive horn test 

performed on locomotive SP 1234, and two records on SP 2345. Record two units for the inspection of 

the noise testing records for two locomotives. 

Example 3: An inspector monitors three noise testing sessions on SP 4567, and then reviews three 

noise testing records regarding that same locomotive. Record one unit for the locomotive and testing 

records involved. 

Note 1: This activity code should only be used by inspectors who have been trained to inspect 

locomotive horn testing records. 

Note 2: This activity code should not be used with Part 227 Occupational Noise Exposure inspections, 

(activity code 227N), or when performing a noise test (activity code NOIS). 

NOIS ALL Noise Tests – The purpose of this inspection is to perform a noise test in accordance with Federal 

regulations. This activity code should only be used by inspectors who have attended the FRA training 

course regarding the equipment used to conduct these inspections. Record one unit for each day or 

partial day of an inspection. 

 

This activity code should not be used with Part 227 Occupational Noise Exposure inspections, (activity 

code 227N), or when reviewing noise records (activity code NOIR). 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

RADX H, O, T Radar Speed Monitoring – The purpose of this inspection is to monitor and/or accurately validate the 

speed of trains and railroad equipment for compliance with Federal regulations and/or railroad operating 

rules. Record one unit for each speed monitoring session and one subunit for each locomotive, train, or 

railroad equipment on the rail monitored. Non-compliance with railroad operating rules should be 

recorded under activity code 217O. 

Note 1: When entering this code, the inspector must indicate the initials and number of the lead 

locomotive, or a locomotive within the consist, in the Train # / Site Field. This Field permits the entry 

of 15 characters. Each train or piece of equipment monitored will require a new line item. 

Note 2: FRA and participating state employees must not perform radar monitoring sessions unless they 

received a certificate of qualification from an FRA employee who holds a current certificate as a 

stationary radar trainer. See Chapter 3 of the General Manual for a complete discussion of FRA policy. 

RMM T, S Roadway Maintenance Machine & Hi-Rail – The purpose of this inspection is to document an 

observation or inspection concerning § 214 Subpart D, On-Track Roadway Maintenance Machines and 

Hi-Rail Vehicles. Record one unit for each Roadway Maintenance Machine or Hi-Rail Vehicle 

inspected. 

Example: If a large scale tie unit consisting of 20 roadway maintenance machines and one Hi-Rail 

vehicle is operating on the tracks, and only five of those machines are inspected, then record five units. 

Note: If a machine operator fails to comply with railroad rules not covered by Part 214 or any Federal 

regulation the inspector must note the non-compliance by recording it using a Non-FRA defect under 

activity code 217O, as provided in the guidelines of that activity code. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

RULE ALL Rulebook Review - The purpose of this inspection is to record an inspector’s review or formal 

discussion with a railroad manager, regarding railroad rules that will determine if they accurately 

correlate with current FRA regulations. Record one unit for each day, or partial day, spent reviewing a 

railroad rule(s) for compliance with Federal regulations. Record a subunit for each CFR section 

involved. Only comments should be recorded under this activity code. Any defects should be recorded 

under the proper corresponding activity code. 

Note: Inspections regarding reviewing railroad rules to ensure compliance regarding §232.103 (n) and 

Part 218 Subpart F should not be recorded under this activity code. Inspectors should reference activity 

code 232X and 218O respectively for those railroad rule inspections. 

Example 1: An inspection of NEBR railroad’s rulebook determined that railroad rules regarding signal 

systems (Part 234 and Part 236) comply with Federal regulations. Record one unit and two subunits. 

Example 2: An inspection that included discussions with railroad managers regarding NEBR railroad’s 

rulebook and bulletins determined that the railroad’s rules regarding Part 217 and Part 220 Subpart C, 

correlated with FRA regulations. Record one unit and two subunits. 
Multi-discipline Code Table of Definitions 

Revised January 17, 2012

Activity Discipline Definition 

RWP O, S, T Roadway Worker Protection – The purpose of this inspection is to determine compliance with Part 

214 Subpart C, Roadway Worker Protection (RWP). Record one unit for an individual worker or group 

of employees (with a roadway worker in charge) at a specific location. This will include attending a job 

briefing with a group of RWP employees. Record each train required to provide an audible warning 

signal as a separate unit, and each employee requiring RWP as a subunit. 

Note: When performing multi-point inspection work with the same employee (or group of employees), 

record only one unit for determining compliance, and one subunit for each employee of the workgroup 

per day. 

Example 1: When observing or inspecting a large production crew, record a separate unit for each 

different location where an employee (or group of employees) is monitored for compliance. E.g. large 

projects may have multiple teams or workgroups at various locations along the right of way, record each 

worker, team or workgroup at each different location as a separate unit. 

Example 2: You observe an RWP crew consisting of one employee-in-charge and 20 track employees 

together at a single location. Record one unit for the location and 21 subunits for the entire RWP work 

group. 

TCL H, M Tank Car Inspection – The purpose of this inspection includes inspecting for markings, placards, and 

structural integrity, and securement. Record one unit for each ground level inspection that did not

include a top level inspection. This activity code may only be used when assessing compliance with 

§§172.302(a)(1), 172.304, 172.502(a)(1)(i), 172.516(c)(2) and (6), 174.50, 179, & 180. 

TPLH H, M, O In-Train Placement of Placarded Rail Cars, Transport Vehicles, and Freight Containers - The 

purpose of this activity is to determine compliance with positioning in-train of placarded cars, §§174.84 

and 174.85. Record one unit for each train inspected. 
FEDERAL RAILROAD ADMINISTRATION

 

 

OFFICE OF RAILROAD SAFETY

 

VOLUME II – SIGNAL AND TRAIN 

CONTROL REGULATIONS, TECHNICAL 

APPLICATIONS, AND DEFECT CODES

April 2012 
i 

VOLUME II – TABLE OF CONTENTS

49 CFR Part 233 – Signal Systems Reporting Requirements ...................................................... 233-1

49 CFR Part 234 – Grade Crossing Signal System Safety and State Action Plans ................... 234-1

49 CFR Part 235 – Instructions Governing Applications for Approval of a Discontinuance 

or Material Modification of a Signal System or Relief from the Requirements of Part 236 .... 235-1

49 CFR Part 236 – Rules, Standards, and Instructions Governing the Installation, 

Inspection, Maintenance, and Repair of Signal and Train Control Systems, Devices, and 

Appliances ......................................................................................................................................... 236-1 

Reference A: Fouling Section Clearance Point Measurement Diagram 

Reference B: FRA Letter to the Association of American Railroads - 1985 

Reference C: Signal-Related Technical Bulletins and Safety Advisories 
233-1 

49 CFR Part 233 – Signal Systems Reporting Requirements

 § 233.1 Scope. 

 § 233.3 Application. 

 § 233.5 Accidents resulting from signal failure. 

 § 233.7 Signal failure reports. 

 § 233.9 Reports. 

 § 233.11 Civil penalties. 

 § 233.13 Criminal penalty. 
233-2 

§ 233.1 Scope.

This part prescribes reporting requirements with respect to methods of train operation, block 

signal systems, interlockings, traffic control systems, automatic train stop, train control, and cab 

signal systems, or other similar appliances, methods, and systems. 

Application: 

This section identifies the systems, methods, and appliances that are subject to the reporting 

requirements. 

This rule subjects the following to the reporting requirements of this part: 

 Automatic block signal systems 

 Traffic control systems 

 Interlockings 

 Automatic train stop 

 Train control 

 Cab signal systems 

 Other similar appliances, methods, and systems 

An automatic block signal system is a block signal system wherein the use of each block is 

governed by an automatic block signal, cab signal, or both. 

Note: A non-automatic block signal system is a term used to denote any method of maintaining 

an interval of space between trains as distinguished from an automatic block signal system, a 

traffic control system, an automatic cab signal system without roadway signals, or time interval 

system. 

A traffic control system is a block signal system under which train movements are authorized by 

block signals or cab signals whose indications supersede the superiority of trains for both 

opposing and following movements on the same track. 

An interlocking is an arrangement of signals, with or without other signal appliances, which may 

be controlled automatically, automatically with supervisory control, or remotely by an operator 

or dispatcher, and where train movements over all routes are governed by signal indication. 

An automatic train stop system is a system arranged so that its operation will automatically result 

in the application of the brakes until the train has been brought to a stop. 

An automatic train control system is a system arranged so that its operation will automatically 

result in the following: 

1. A full-service application of the brakes, which will continue either until the train is 

brought to a stop, or under control of the engineman, or until its speed is reduced to a 

predetermined rate. 
233-3 

2. When operating under a speed restriction, application of the brakes when the speed of 

the train exceeds the predetermined rate and which will continue until the speed is 

reduced to that rate. 

Automatic train control systems include those systems referred to as speed control systems. 

An automatic cab signal system is a system that provides for the automatic operation of the 

following: 

1. Cab signal, a signal located in the engineer’s compartment or cab, indicating a condition 

affecting the movement of a train and used in conjunction with interlocking signals and 

in conjunction with or in lieu of block signals, and 

2. Cab indicator, a device located in the cab which indicates a condition or a change of 

condition of one or more elements of the system. 

§ 233.3 Application.

(a) Except as provided in paragraph (b) of this section, this part applies to railroads that 

operate on standard gage track which is part of the general railroad system of transportation. 

(b) This part does not apply to rail rapid transit operations conducted over track that is used 

exclusively for that purpose and that is not part of the general system of railroad transportation. 

Application: 

This section makes this part applicable to each common carrier by rail subject to the Signal 

Inspection Act, 49 U.S.C. 205. 

It applies to each railroad that is part of the general rail system engaged in interstate commerce. 

It does not apply to: 

 

 Rapid transit systems 

 Privately owned systems that do not transport interstate commerce 

 Automatic classification yards 

 Highway-rail grade crossing active warning devices

§ 233.5 Accidents resulting from signal failure. 

Each carrier shall report within 24 hours to the Federal Railroad Administration by toll free 

telephone number 800-424-0201, whenever it learns of the occurrence of an accident/incident 

arising from the failure of an appliance, device, method, or system to function or indicate as 

required by part 236 of this title that results in a more favorable aspect than intended or other 

condition hazardous to the movement of a train.

Application: 

This section requires each carrier to call FRA at 800-424-0201 within 24 hours of each 

accident/incident resulting from a false proceed signal indication or failure. 
233-4 

A false proceed signal indication or a false proceed failure is the failure of an appliance, device, 

method, or system to function or indicate as required by the Rules, Standards, and Instructions 

(RS&I) that results in either a more favorable aspect than intended or a condition that is 

hazardous to the movement of a train. 

CLASSIFICATION OF DEFECTS

233.5.A1 Accident/incident resulting from or involving failure of appliance, device, 

method, or system to function or indicate as intended, not reported to FRA within 

24 hours after accident/incident. 

§ 233.7 Signal failure reports.

Each carrier shall report within 15 days each failure of an appliance, device, method, or 

system to function or indicate as required by part 236 of this title that results in a more favorable 

aspect than intended or other condition hazardous to the movement of a train. Form FRA 

F6180-14, “Signal Failure Report,” shall be used for this purpose and completed in accordance 

with instructions printed on the form.

Application: 

This rule requires that each false proceed failure, including those resulting in an accident/ 

incident, be reported to FRA within 15 days on Form FRA F6180-14, in accordance with the 

instructions contained on the form. Application of this rule includes that the report of each 

instance be complete and correct. 

A false proceed signal indication or a false proceed failure is the failure of an appliance, device, 

method, or system to function or indicate as required by the RS&I that results in either a more 

favorable signal aspect than intended or a condition that is hazardous to the movement of a train. 

CLASSIFICATION OF DEFECTS

233.7.A1 Report of failure of appliance, device, method, or system to indicate or function 

 as intended not made on prescribed form within 15 days. 

233.7.A2 Report of failure of appliance, device, method, or system to indicate or function as 

intended not complete. 

233.7.A3 Report of failure of appliance, device, method, or system to indicate or function as 

intended not correct. 

§ 233.9 Reports. 

Not later than April 1, 1997, and every 5 years thereafter, each carrier shall file with FRA a 

signal system status report titled “Signal System Five-Year Report” on a form to be provided by 

FRA in accordance with instructions and definitions provided on the report.
233-5 

Application: 

This section requires each carrier to file a “Signal System Five-Year Report” every 5 years. The 

report addresses the status of the filing railroad’s signal systems and methods of train operation. 

It is due no later than April 1 at regular 5-year intervals beginning with the year 1997. The 

report is required to be filed on a form to be provided by FRA in accordance with the instructions 

on the back of the form. Application of this rule requires that the report of each railroad be 

timely, complete, and correct. 

CLASSIFICATION OF DEFECTS

233.9.A1 Five-year signal system status report not filed no later than April 1 of the year in 

which it is due. 

233.9.A2 Five-year signal system status report not complete. 

233.9.A3 Five-year signal system status report not correct. 

§ 233.11 Civil penalty.

Any person (an entity of any type covered under 1 U.S.C. 1, including but not limited to the 

following: a railroad; a manager, supervisor, official, or other employee or agent of a railroad; 

any owner, manufacturer, lessor, or lessee of railroad equipment, track, or facilities; any 

independent contractor providing goods or services to a railroad; and any employee of such 

owner, manufacturer, lessor, lessee, or independent contractor) who violates any requirement of 

this part or causes the violation of any such requirement is subject to a civil penalty of at least 

$650 and not more than $25,000 per violation, except that: Penalties may be assessed against 

individuals only for willful violations, and, where a grossly negligent violation or a pattern of 

repeated violations has created an imminent hazard of death or injury to persons, or has caused 

death or injury, a penalty not to exceed $100,000 per violation may be assessed. Each day a 

violation continues shall constitute a separate offense. See Appendix A to this part for a 

statement of agency civil penalty policy.

Application: 

This section prescribes a civil penalty for failure to file reports as required by this part. 

This rule establishes that a carrier is liable for maximum penalty of $25,000 for each offense or 

failure to file reports as required, except in extraordinary cases, where the penalty may be 

aggravated to $100,000. Each day a failure or refusal to file continues is a separate offense. 

§ 233.13 Criminal penalty.

Whoever knowingly and willfully-- 

(a) Makes, causes to be made, or participates in the making of a false entry in reports 

required to be filed by this part; or 

(b) Files a false report or other document required to be filed by this part is subject to a 

$5,000 fine and 2 years imprisonment as prescribed by 49 U.S.C. 522(a) and section 209(e) of 

the Federal Railroad Safety Act of 1970, as amended (45 U.S.C. 438(e)). 
233-6 

Appendix A to Part 233 – Schedule of Civil Penalties1 

Section Violation Willful

233.5 Accidents resulting from signal failure $2,500 $5,000 

233.7 Signal failure reports $5,000 $7,500 

233.9 Annual reports $1,000 $2,000

Application: 

This section prescribes a criminal penalty for filing a false report or other document required by 

this part. 

The rule subjects any person who knowingly and willfully makes, causes to be made, or 

participates in the making of a false entry in an accident report, false proceed report, or 5-year 

report required by this part to a fine of $5,000 and/or 2 years’ imprisonment. 
234-1 

49 CFR Part 234 – Grade Crossing Signal System Safety and State Action

Plans

Compliance Policy 

Subpart A – General 

 § 234.1 Scope. 

 § 234.3 Application. 

 § 234.5 Definitions. 

 § 234.6 Penalties. 

Subpart B – Reports and Plans 

 § 234.7 Accidents involving grade crossing signal failure. 

 § 234.9 Grade crossing signal system failure reports. 

 § 234.11 State highway-rail grade crossing action plans. 

Subpart C – Response to Reports of Warning System Malfunction 

 § 234.101 Employee notification rules. 

 § 234.103 Timely response to report of malfunction. 

 § 234.105 Activation failure. 

 § 234.106 Partial activation. 

 § 234.107 False activation. 

 § 234.109 Recordkeeping. 

Subpart D – Maintenance, Inspection, and Testing 

Maintenance Standards 

 § 234.201 Location of plans. 

 § 234.203 Control circuits. 

 § 234.205 Operating characteristics of warning system apparatus. 

 § 234.207 Adjustment, repair, or replacement of component. 

 § 234.209 Interference with normal functioning of system. 

 § 234.211 Security of warning system apparatus. 

 § 234.213 Grounds. 

 § 234.215 Standby power system. 

 § 234.217 Flashing light units. 

 § 234.219 Gate arm lights and light cable. 

 § 234.221 Lamp voltage. 

 § 234.223 Gate arm. 

 § 234.225 Activation of warning system. 

 § 234.227 Train detection apparatus. 

 § 234.229 Shunting sensitivity.

 § 234.231 Fouling wires. 

 § 234.233 Rail joints. 

 § 234.235 Insulated rail joints. 

 § 234.237 Reverse switch cut-out circuit. 
234-2 

 § 234.239 Tagging of wires and interference of wires or tags with signal apparatus. 

 § 234.241 Protection of insulated wire; splice in underground wire. 

 § 234.243 Wire on pole line and aerial cable. 

 § 234.245 Signs. 

 

Inspections and Tests 

 § 234.247 Purpose of inspections and tests; removal from service of relay or device failing 

to meet test requirements. 

 § 234.249 Ground tests. 

 § 234.251 Standby power. 

 § 234.253 Flashing light units and lamp voltage. 

 § 234.255 Gate arm and gate mechanism. 

 § 234.257 Warning system operation. 

 § 234.259 Warning time. 

 § 234.261 Highway traffic signal pre-emption. 

 § 234.263 Relays. 

 § 234.265 Timing relays and timing devices. 

 § 234.267 Insulation resistance tests, wires in trunking and cables. 

 § 234.269 Cut-out circuits. 

 § 234.271 Insulated rail joints, bond wires, and track connections. 

 § 234.273 Results of inspections and tests. 

 

Requirements for Processor-Based Systems 

 § 234.275 Processor-based systems. 

 
234-3 

Compliance Policy

The purpose of these regulations is to provide for the safety of users of highway-rail grade 

crossings, including motor vehicle occupants, non-motorized vehicle users, and pedestrians. It is 

FRA’s policy to promote voluntary compliance with these minimum safety standards. If 

voluntary compliance is not forthcoming, civil penalty sanctions may be employed as necessary 

to secure compliance. 

In determining whether use of civil penalty sanctions is necessary, the inspector will take into 

consideration whether the railroad has installed and maintained the installation in a manner likely 

to provide for its proper functioning in the interval between required inspections and tests. The 

inspector shall also take into account the harshness of the environment in which the installation 

is required to function. Civil penalty sanctions should not be recommended for conditions that 

the railroad could not have prevented through use of due diligence, provided those conditions 

occurred subsequent to a previous inspection or test of the system. 

Conditions that arise through no fault on the part of the railroad include, for example: 

 Gate arm breakage 

 Lamp outage or damage to flashing light units, due to mechanical damage 

 Gate arm light not securely fastened to gate arm, due to mechanical damage 

In other cases, normal operation of the system may result in occasional component failure or lack 

of adjustment that is neither predictable nor reasonably preventable, for example: 

 Lamp outage due to normal burnout of filament, where outages represent failure at an 

expected rate due to expired service life 

 Switch circuit controller connection loose at time of quarterly inspection 

 Insulation in insulated joint in bad condition at time of quarterly inspection 

 Switch circuit controller not securely fastened in place at time of quarterly inspection 

In summary, certain component failures may occur as a result of vandalism, inadvertent contact 

with the installation by motor vehicles, or lack of proper maintenance. In individual cases such 

as those cited above, the inspector should record a defect and the railroad will be expected to 

promptly remedy the condition as required by 49 CFR § 234.207. 

While certain conditions may seem minor in nature when viewed individually, any failure to 

correct could result in an activation failure, partial activation, or false activation. Accordingly, 

when an inspector encounters a pattern involving any such conditions, indicating lack of proper 

inspection or maintenance, civil penalties should be employed as necessary. (See 49 CFR Part 

209, Appendix A)

 
234-4 

Subpart A – General

§ 234.1 Scope. 

 This part imposes minimum maintenance, inspection, and testing standards for highway-rail 

grade crossing warning systems. This part also prescribes standards for the reporting of failures 

of such systems and prescribes minimum actions railroads must take when such warning systems 

malfunction. This part also requires particular identified States to develop State highway-rail 

grade crossing action plans. This part does not restrict a railroad from adopting and enforcing 

additional or more stringent requirements not inconsistent with this part.

§ 234.3 Application. 

 With the exception of § 234.11, this part applies to all railroads except: 

 (a) A railroad that exclusively operates freight trains only on track which is not part of the 

general railroad system of transportation; 

 (b) Rapid transit operations within an urban area that are not connected to the general 

railroad system of transportation; and 

 (c) A railroad that operates passenger trains only on track inside an installation that is 

insular; i.e., its operations are limited to a separate enclave in such a way that there is no 

reasonable expectation that the safety of the public-except a business guest, a licensee of the 

railroad or an affiliated entity, or a trespasser-would be affected by the operation. An operation 

will not be considered insular if one or more of the following exists on its line: 

 (1) A public highway-rail crossing that is in use; 

 (2) An at-grade rail crossing that is in use; 

 (3) A bridge over a public road or waters used for commercial navigation; or 

 (4) A common corridor with a railroad, i.e., its operations are within 30 feet of those of any 

railroad.

Application: 

The following examples address specific types of rail operations and whether § 234.3 applies to 

that operation: 

1. Rail freight operations. This part applies to all freight railroads that are part of the 

general railroad system of transportation. FRA’s regulations generally exclude railroads 

whose entire operations are confined to an industrial installation, e.g., “plant railroads” 

such as those in steel mills that do not go beyond the plant’s boundaries. However, even 

where a railroad operates outside of the general system, other railroads that are part of 

that system may have occasion to enter the first railroad=s property. In that case, the plant 

railroad would have to meet FRA’s highway-rail grade crossing warning system 

standards if a general system railroad operated over the grade crossing. These regulations 

do not apply to a freight-carrying railroad (and the highway-rail grade crossings over 

which it operates) that is not part of the general railroad system of transportation. Both 

public and private crossings over which general system railroads operate are covered by 

this part. 
234-5 

2. Rail rapid transit. This part does not apply to rail rapid transit operations conducted over 

track that is used exclusively for that purpose and that is not part of the general railroad 

system of transportation. 

Note: See FRA/Federal Transit Administration Shared Corridor Policy, Federal 

Register, Volume 65, No. 132, July 10, 2000, for further information. 

3. Rail passenger operations. This part does apply to passenger railroad operations if any of 

the following exists on the line of railroad: (a) a public highway-rail grade crossing that 

is in use; (b) an at-grade rail crossing that is in use; (c) a bridge over a public road or 

waters used for commercial navigation; or (d) its operations are within 30 feet of those of 

any other railroad. If any of these conditions exist, all highway-rail grade crossings over 

which the railroad operates, both public and private crossings, are subject to this rule. It 

is important to note that the fact that a passenger railroad is not connected to the general 

railroad system does not in itself affect a railroad’s duty to comply with this part. An 

analysis must be made as to the presence of the above-mentioned factors. 

When a manually operated highway-rail grade crossing active warning system contains 

components covered by this part, those components shall comply with the applicable rule 

requirements. (See Technical Bulletin S-96-09.)

§ 234.5 Definitions. 

 As used in this part: 

 Activation failure means the failure of an active highway-rail grade crossing warning system 

to indicate the approach of a train at least 20 seconds prior to the train's arrival at the crossing, or 

to indicate the presence of a train occupying the crossing, unless the crossing is provided with an 

alternative means of active warning to highway users of approaching trains. (This failure 

indicates to the motorist that it is safe to proceed across the railroad tracks when, in fact, it is not 

safe to do so.) A grade crossing signal system does not indicate the approach of a train within 

the meaning of this paragraph if–more than 50 percent of the flashing lights (not gate arm lights) 

on any approach lane to the crossing are not functioning as intended, or in the case of an 

approach lane for which two or more pairs of flashing lights are provided, there is not at least 

one flashing light pair operating as intended. Back lights on the far side of the crossing are not 

considered in making these determinations. 

 Appropriately equipped flagger means a person other than a train crewmember who is 

equipped with a vest, shirt, or jacket of a color appropriate for daytime flagging such as orange, 

yellow, strong yellow green or fluorescent versions of these colors or other generally accepted 

high visibility colors. For nighttime flagging, similar outside garments shall be retro reflective. 

Acceptable hand signal devices for daytime flagging include “STOP/SLOW” paddles or red 

flags. For nighttime flagging, a flashlight, lantern, or other lighted signal shall be used. 

Inasmuch as Part VI of the Federal Highway Administration’s Manual on Uniform Traffic 

Control Devices addresses standards and guides for flaggers and flagging equipment for highway 

traffic control, FRA recommends that railroads be aware of the standards and follow them to the 

greatest extent possible. Copies of the latest MUTCD provisions regarding flagging will be 

available from FRA, as well as FMCSA, as changes are made in this area. 
234-6 

 Credible report of system malfunction means specific information regarding a malfunction 

at an identified highway-rail crossing, supplied by a railroad employee, law enforcement officer, 

highway traffic official, or other employee of a public agency acting in an official capacity. 

 False activation means the activation of a highway-rail grade crossing warning system 

caused by a condition that requires correction or repair of the grade crossing warning system. 

(This failure indicates to the motorist that it is not safe to cross the railroad tracks when, in fact, 

it is safe to do so.) 

 Highway-rail grade crossing means a location where a public highway, road, street, or 

private roadway, including associated sidewalks and pathways, crosses one or more railroad 

tracks at grade. 

 Partial activation means activation of a highway-rail grade crossing warning system 

indicating the approach of a train, however, the full intended warning is not provided due to one 

of the following conditions: 

 (1) At non-gated crossings equipped with one pair of lights designed to flash alternately, one 

of the two lights does not operate properly (and approaching motorists can not clearly see 

flashing back lights from the warning lights on the other side of the crossing); 

 (2) at gated crossings, the gate arm is not in a horizontal position; or 

 (3) at gated crossings, any portion of a gate arm is missing if that portion normally had a gate 

arm flashing light attached. 

 Train means one or more locomotives, with or without cars. 

 Warning system malfunction means an activation failure, a partial activation, or a false 

activation of a highway-rail grade crossing warning system.

Application: 

Activation Failure. An activation failure is the failure of an active highway-rail grade crossing 

warning system to indicate the approach of a train at least 20 seconds prior to the train’s arrival 

at the crossing, or to indicate the presence of a train occupying the crossing, unless the crossing 

is provided with an alternative means of active warning to highway users of approaching trains. 

(This failure indicates to the motorist that it is safe to proceed across the railroad tracks when, in 

fact, it is not safe to do so.) 

A grade crossing warning system does not indicate the approach of a train within the meaning of 

this paragraph if: 

1. More than 50 percent of the flashing lights (not gate arm lights) on any approach lane to 

the crossing are not functioning as intended. 

2. In the case of an approach lane where two or more pairs of flashing lights are provided, 

there is not at least one flashing light pair operating as intended. 

Back lights on the far side of the crossing are not considered in making these determinations. 

It shall not be deemed an activation failure if alternative means, as set forth in § 234.105, are 

used to provide warning to highway users approaching the crossing where an active warning 

system is inoperative. 

Appropriately Equipped Flagger. A person, other than a train crewmember, who is equipped 

with a vest, shirt, or jacket of a color appropriate for daytime flagging such as orange, yellow, 

strong yellow-green, fluorescent versions of these colors, or other generally accepted high-
234-7 

visibility colors. For nighttime flagging, similar outside garments shall be retro-reflective. 

Acceptable hand signal devices for daytime flagging include “STOP/SLOW” paddles or red 

flags. For nighttime flagging, a flashlight, lantern, or other lighted signal shall be used. 

Inasmuch as Part VI of the Federal Highway Administration’s (FHWA) Manual on Uniform 

Traffic Control Devices (MUTCD) addresses standards and guides for flaggers and flagging 

equipment for highway traffic control, FRA recommends that railroads be aware of the standards 

and follow them to the greatest extent possible. Copies of the latest MUTCD provisions 

regarding flagging will be available from FRA and FHWA as changes are made in this area. 

Credible Report of System Malfunction. Specific information regarding a malfunction at an 

identified highway-rail grade crossing, supplied by a railroad employee, law enforcement officer, 

highway traffic official, or other employee of a public agency acting in an official capacity. 

False Activation. The activation of a highway-rail grade crossing warning system caused by a 

condition that requires correction or repair of the grade crossing warning system. (This failure 

indicates to the highway user that it is not safe to cross the railroad tracks when, in fact, it is safe 

to do so.) 

Highway-Rail Grade Crossing. A location where a public highway, road, street, or private 

roadway, including associated sidewalks and pathways, crosses one or more railroad tracks at 

grade. 

Partial Activation. The activation of a highway-rail grade crossing warning system indicating 

the approach of a train, however, the full intended warning is not provided due to one of the 

following conditions: 

1. At non-gated crossings equipped with one pair of lights designed to flash alternately, one 

of the two lights does not operate properly (and approaching motorists can not clearly see 

flashing back lights from the warning lights on the other side of the crossing); 

2. At gated crossings, the gate arm is not in a horizontal position; or 

3. At gated crossings, any portion of a gate arm is missing if that portion normally had a 

gate arm flashing light attached. 

Train. One or more locomotives, with or without cars. 

Warning System Malfunction. An activation failure, a partial activation, or a false activation 

of a highway-rail grade crossing warning system.

§ 234.6 Penalties. 

 (a) Civil penalty. Any person (an entity of any type covered under 1 U.S.C. 1, including but 

not limited to the following: a railroad; a manager, supervisor, official, or other employee or 

agent of a railroad; any owner, manufacturer, lessor, or lessee of railroad equipment, track, or 

facilities; any independent contractor providing goods or services to a railroad; and any 

employee of such owner, manufacturer, lessor, lessee, or independent contractor) who violates 

any requirement of this part or causes the violation of any such requirement is subject to a civil 

penalty of at least $650, but not more than $25,000 per violation, except that: penalties may be 
234-8 

assessed against individuals only for willful violations, and where a grossly negligent violation 

or a pattern of repeated violations has created an imminent hazard of death or injury to persons, 

or has caused death or injury, a penalty not to exceed $100,000 per violation may be assessed. 

Each day a violation continues shall constitute a separate offense. Appendix A to this part 

contains a schedule of civil penalty amounts used in connection with this rule. The railroad is 

not responsible for compliance with respect to any condition inconsistent with the technical 

standards set forth in this part where such variance arises as a result of actions beyond the control 

of the railroad and the railroad could not have prevented the variance through the exercise of due 

diligence. The foregoing sentence does not excuse any instance of noncompliance resulting from 

the actions of the railroad's employees, agents, or contractors.

 (b) Criminal penalty. Whoever knowingly and willfully makes, causes to be made, or 

participates in the making of a false entry in reports required to be filed by this part, or files a 

false report or other document required to be filed by this part, except for any document filed 

pursuant to § 234.11, is subject to a $5,000 fine and 2 years imprisonment as prescribed by 49 

U.S.C. 522(a) and 21311(a).

Subpart B – Reports

§ 234.7 Accidents involving grade crossing signal failure.

 (a) Each railroad shall report to FRA every impact between on-track railroad equipment and 

an automobile, bus, truck, motorcycle, bicycle, farm vehicle, or pedestrian at a highway-rail 

grade crossing involving an activation failure. Notification shall be provided to the National 

Response Center within 24 hours of occurrence at (800) 424-0201. Complete reports shall 

thereafter be filed with FRA pursuant to § 234.9 of this part (activation failure report) and 49 

CFR 225.11 (accident/incident report). 

 (b) Each telephone report must state the: 

 (1) Name of the railroad; 

 (2) Name, title, and telephone number of the individual making the report; 

 (3) Time, date, and location of accident; 

 (4) U.S. DOT-AAR Grade Crossing Identification Number; 

 (5) Circumstances of the accident, including operating details of the grade crossing warning 

 device; 

 (6) Number of persons killed or injured, if any; 

 (7) Maximum authorized train speed; and 

 (8) Posted highway speed limit, if known.

Application: 

This section requires each railroad to report each accident/incident, as defined in § 225.5(1), 

involving highway-rail grade crossing warning system activation failure, by toll-free telephone 

number (800-424-0201), within 24 hours. This telephone report is not a substitute for required 

written reports. 

An accident/incident, as defined in § 225.5(1), is an impact between on-track railroad equipment 

and an automobile, bus, truck, motorcycle, bicycle, farm vehicle, or pedestrian. When an 

accident/incident occurs, involving an activation failure of an active highway-rail grade crossing 

warning system, the telephone report must be made. 
234-9 

It shall not constitute an activation failure if on-track railroad equipment is not designed, 

equipped, and relied upon to activate such highway-rail grade crossing warning system. 

An “activation failure” is as defined in § 234.5. 

CLASSIFICATION OF DEFECTS

234.7.A1 Impact involving a highway-rail grade crossing warning system activation failure 

not reported to National Response Center by telephone within 24 hours after 

occurrence. 

234.7.B1 Telephone report not complete. 

234.7.B2 Telephone report not correct. 

§ 234.9 Grade crossing signal system failure reports.

 Each railroad shall report to FRA within 15 days each activation failure of a highway-rail 

grade crossing warning system. FRA Form No. 6180-83, “Highway-Rail Grade Crossing 

Warning System Failure Report,” shall be used for this purpose and completed in accordance 

with instructions printed on the form.

Application:

This section requires each railroad to report within 15 days each activation failure of an active 

highway-rail grade crossing warning system. 

This section requires that each activation failure, including those resulting in an accident/ 

incident, as defined in § 225.5(1), be reported to FRA within 15 days on Form FRA F6180.83 in 

accordance with the instructions contained on the form. Application of this rule includes that the 

report of each instance be complete and correct. The completed form shall be submitted to the 

FRA Regional Administrator of the region in which the railroad is headquartered. 

An activation failure is as defined in § 234.5. 

It shall not constitute an activation failure if on-track railroad equipment is not designed, 

equipped, and relied upon to activate the highway-rail grade crossing warning system. 

CLASSIFICATION OF DEFECTS

234.9.A1 Report of activation failure not submitted on prescribed form within 15 days. 

234.9.A2 Report of activation failure not complete. 

234.9.A3 Report of activation failure not correct. 

§ 234.11 State highway-rail grade crossing action plans. 

(a) Purpose. The purpose of this section is to reduce collisions at highway-rail grade 

crossings in the ten States that have had the most highway-rail grade crossing collisions, on 
234-10 

average, during the calendar years 2006, 2007, and 2008. This section does not restrict any other 

State, or other entity, from adopting a highway-rail grade crossing action plan. This section also 

does not restrict any of the States required to develop action plans under this section from 

adopting a highway-rail grade crossing action plan with additional or more stringent 

requirements not inconsistent with this section. 

(b) Application. This section applies to the ten States that have had the most highway-rail 

grade crossing collisions, on average, during the calendar years 2006, 2007, and 2008. 

(c) Action plans. (1) The ten identified States shall each develop a State highway-rail grade 

crossing action plan and submit such a plan to FRA for review and approval not later than 

August 27, 2011. 

(2) A State highway-rail grade crossing action plan shall: 

(i) Identify specific solutions for improving safety at crossings, including highway-rail grade 

crossing closures or grade separations; 

(ii) Focus on crossings that have experienced multiple accidents or are at high risk for such 

accidents; and 

(iii) Cover a five-year period. 

(d) Review and approval. (1) State highway-rail grade crossing action plans required under 

paragraph (c) of this section shall be submitted for FRA review and approval using at least one 

of the following methods: Mail to the Associate Administrator for Railroad Safety/Chief Safety 

Officer, U.S. Department of Transportation, Federal Railroad Administration, 1200 New Jersey 

Ave. SE., Washington, DC 20590; or e-mail to rrs.correspondence@fra.dot.gov. 

(2) FRA will review and approve or disapprove a State highway-rail graded crossing action 

plan submitted pursuant to paragraph (d) of this section within 60 days of receipt. 

(3) If the proposed State highway-rail graded crossing action plan is disapproved, FRA will 

notify the affected State as to the specific areas in which the proposed plan is deficient. A State 

shall correct all deficiencies within 30 days following receipt of written notice from FRA. 

(4) FRA may condition the awarding of any grants under 49 U.S.C. 20158, 20167, or 22501 

to an identified State on the development of an FRA approved State highway-rail graded 

crossing action plan. 

Application: 

This section requires that the ten States that have had the most highway-rail grade crossing 

collisions, on average—during the calendar years 2006, 2007, and 2008—develop a State 

highway-rail grade crossing action plan and submit such a plan to FRA for review and approval 

not later than August 27, 2011. It further identifies what information shall be included and the 

process regarding FRA’s review and approval of each plan. 

This section requires an action plan from the ten identified States by not later than the date 

indicated but does not require subsequent plans beyond that date. 

Subpart C – Response to Reports of Warning System Malfunction. 

§ 234.101 Employee notification rules.

 Each railroad shall issue rules requiring its employees to report to persons designated by that 

railroad, by the quickest means available, any warning system malfunction.
234-11 

Application:

This section requires that each railroad issue rules requiring that its employees report 

malfunctions of highway-rail grade crossing warning systems to a designated railroad employee 

or employees, and that such reports shall be made by the quickest means of communications 

available. 

The intent of this section is that each railroad issue to its employees rules that require its 

employees to report by the quickest means available, any activation failure, partial activation, or 

false activation of a highway-rail grade crossing active warning system. The railroad must 

designate a person or persons to whom all such reports must be made. The railroad may do so by 

inserting the information in their timetable, special instructions, general orders, etc. 

CLASSIFICATION OF DEFECTS

234.101.A1 Rules not issued requiring railroad employees to report any malfunction of 

highway-rail grade crossing warning system to designated persons by quickest 

means available. 

§ 234.103 Timely response to report of malfunction.

 (a) Upon receipt of a credible report of a warning system malfunction, a railroad having 

maintenance responsibility for the warning system shall promptly investigate the report and 

determine the nature of the malfunction. The railroad shall take appropriate action as required by 

§ 234.207. 

 (b) Until repair or correction of the warning system is completed, the railroad shall provide 

alternative means of warning highway traffic and railroad employees in accordance with §§ 

234.105, 234.106, or 234.107 of this part. 

 (c) Nothing in this subpart requires repair of a warning system, if, acting in accordance with 

applicable State law, the railroad proceeds to discontinue or dismantle the warning system. 

However, until repair, correction, discontinuance, or dismantling of the warning system is 

completed, the railroad shall comply with this subpart to ensure the safety of the traveling public 

and railroad employees. 

Application:

This section requires that once a credible report of a malfunction of a highway-rail grade 

crossing warning system has been received, the railroad having maintenance responsibility for 

the warning system shall promptly investigate the report. Further, if such malfunction is found 

to be caused by a faulty component, such component shall be adjusted, repaired, or replaced 

without undue delay, as required by § 234.207. 

A “credible report of a highway-rail grade crossing warning system malfunction” is defined in § 

234.5 as a report from a railroad employee, law enforcement officer, highway traffic official, or 

other employee of a public agency acting in an official capacity. A “warning system 

malfunction” is defined in § 234.5 as an activation failure, a partial activation, or a false 

activation of a highway-rail grade crossing warning system. 
234-12 

This section also requires that the railroad provide alternative means of warning highway traffic 

and railroad employees in accordance with §§ 234.105, 234.106, or 234.107, until the 

malfunction has been investigated and repair or correction of the warning system is completed, 

or until the system is discontinued or dismantled. 

This section specifies that nothing in these regulations forces a railroad to continually repair a 

warning system that, under State law, may be retired. However, a railroad must still comply with 

this subpart during retirement proceedings. This section requires that, until repair, correction, 

discontinuance, or dismantling of the system is completed, the railroad must comply with this 

part. 

In summary, each railroad must take prompt action to investigate any credible report of a 

malfunctioning highway-rail grade crossing warning system, and each malfunction shall be 

corrected without undue delay. This section does not require a railroad to continue to repair and 

maintain a highway-rail grade crossing warning system that might otherwise be discontinued 

under State laws. The railroad may elect to discontinue and disassemble the warning system, but 

until the warning system is physically removed, the railroad shall provide alternative means of 

warning the highway users and railroad employees. 

CLASSIFICATION OF DEFECTS

234.103.A1 Credible report of highway-rail grade crossing warning system malfunction not 

promptly investigated. 

234.103.B1 Action not taken to provide alternative means of warning highway traffic and 

railroad employees until repairs or correction of warning system is completed. 

234.103.C1 Action not taken to provide alternative means of warning highway traffic and 

railroad employees until dismantling of a discontinued warning system is 

completed. 

§ 234.105 Activation failure.

 Upon receipt of a credible report of warning system malfunction involving an activation 

failure, a railroad having maintenance responsibility for the warning system shall promptly 

initiate efforts to warn highway users and railroad employees at the subject crossing by taking 

the following actions: 

 (a) Prior to any train's arrival at the crossing, notify the train crew of the report of activation 

failure and notify any other railroads operating over the crossing; 

 (b) Notify the law enforcement agency having jurisdiction over the crossing, or railroad 

police capable of responding and controlling vehicular traffic; and 

 (c) Provide for alternative means of actively warning highway users of approaching trains, 

consistent with the following requirements (see appendix B for a summary chart of alternative 

means of warning): 

 (1)(i) If an appropriately equipped flagger provides warning for each direction of highway 

traffic, trains may proceed through the crossing at normal speed. 

 (ii) If at least one uniformed law enforcement officer (including a railroad police officer) 

provides warning to highway traffic at the crossing, trains may proceed through the crossing at 

normal speed. 
234-13 

 (2) If an appropriately equipped flagger provides warning for highway traffic, but there is 

not at least one flagger providing warning for each direction of highway traffic, trains may 

proceed with caution through the crossing at a speed not exceeding 15 miles per hour. Normal 

speed may be resumed after the locomotive has passed through the crossing. 

 (3) If there is not an appropriately equipped flagger or uniformed law enforcement officer 

providing warning to highway traffic at the crossing, each train must stop before entering the 

crossing and permit a crewmember to dismount to flag highway traffic to a stop. The locomotive 

may then proceed through the crossing, and the flagging crewmember may reboard the 

locomotive before the remainder of the train proceeds through the crossing. 

 (d) A locomotive's audible warning device shall be activated in accordance with railroad 

rules regarding the approach to a grade crossing.

Application:

This section requires that a railroad having maintenance responsibility for a warning system take 

prompt action to provide alternative means of warning highway users and railroad employees at 

a specific crossing where a credible report of a system malfunction involving an activation 

failure has been received. This section further requires specific actions to be followed to provide 

an alternative warning. 

When a railroad receives a credible report of a system malfunction involving an activation 

failure, it is required to take prompt action to notify train crews and other railroads operating 

over such crossing prior to the next train operation over the crossing. Further, the railroad is 

required to notify the law enforcement agency having jurisdiction over such crossing or the 

railroad police who are capable of responding to control vehicular traffic at the crossing. Finally, 

the railroad must take action to assure that its employees, or a law enforcement agency, provide 

the required alternative means of warning for highway users at the crossing. 

A credible report of a highway-rail grade crossing warning system malfunction is defined in 

§ 234.5 as a report from a railroad employee, law enforcement officer, highway traffic official, 

or other employee of a public agency acting in an official capacity. A warning system 

malfunction is defined in § 234.5 as an activation failure, a partial activation, or a false activation 

of a highway-rail grade crossing warning system. 

At crossings where it has been determined that the warning system is not functioning as 

intended, § 234.207’s requirement for adjustment, repair, or replacement without undue delay 

applies. 

When the alternative warning consists of at least one uniformed law enforcement officer, one 

uniformed railroad police officer, or an appropriately equipped flagger for each direction of 

highway traffic at the crossing, trains may proceed over the crossing at normal speed. If an 

appropriately equipped flagger provides the alternative means of warning but there is less than 

one flagger for each direction of highway traffic available at the crossing, trains must not exceed 

15 mph until the locomotive has passed over the crossing. If there is no appropriately equipped 

flagger, uniformed law enforcement officer, or uniformed railroad police officer to provide 

alternative warning, each train must stop and a member of the train crew must dismount the 

locomotive and flag highway traffic to a stop before the train occupies the crossing. 
234-14 

Note: The appropriately equipped flagger requirements are very narrow in scope, in that only in 

the event the flagger is being used as alternative warning to allow train movement through the 

crossing at normal speed do the appropriately equipped provisions apply. 

This section also requires that the locomotive audible warning device be activated in accordance 

with railroad rules when approaching a crossing where an activation failure has occurred. The 

reference to railroad rules has to do with the manner in which the horn is sounded. This section 

preempts any State or local “whistle bans” with respect to use of the horn under the 

circumstances addressed in this section. (See Technical Bulletin S-96-08)

CLASSIFICATION OF DEFECTS

234.105.A1 Train crew or other railroads operating over crossing not notified of activation 

failure prior to arrival of train at crossing. 

234.105.B1 Law enforcement agency having jurisdiction or railroad police not promptly 

notified of activation failure. 

234.105.C1 Alternative means of actively warning highway users not provided at crossing 

where credible report indicates activation failure has occurred. 

234.105.C2 Train passed over crossing at normal speed without alternative means of warning 

being provided by the required number of appropriately equipped flaggers, a 

uniformed law enforcement officer, a or uniformed railroad police officer. 

234.105.C3 Train passed over crossing at a speed of more than 15 mph with alternative means 

of warning not being provided by at least one appropriately equipped flagger for 

each direction of highway traffic. 

234.105.C4 Flagger not equipped with required vest, shirt, or jacket. 

234.105.C5 Flagger not equipped with required flagging equipment. 

234.105.C6 Train failed to stop at crossing when the required alternative means of warning 

was not provided. 

234.105.C7 After train stopped, crewmember failed to get off train and flag highway traffic to 

a stop when the required alternative means of warning was not provided. 

234.105.D1 Locomotive audible warning device not sounded in accordance with the railroad’s 

rules as train approached crossing where activation failure has been identified by 

a credible report. 

§ 234.106 Partial activation.

 Upon receipt of a credible report of a partial activation, a railroad having maintenance 

responsibility for the warning system shall promptly initiate efforts to warn highway users and 
234-15 

railroad employees at the subject crossing in the same manner as required for false activations (§ 

234.107).

Application:

This section requires that a railroad having maintenance responsibility for a warning system take 

prompt action to provide alternative means of warning highway users and railroad employees at 

a crossing where a credible report of a system malfunction involving a partial activation has been 

received. This section further requires that specific actions be followed to provide that 

alternative warning. 

When a railroad receives a credible report of a system malfunction involving a partial activation, 

it is required to take prompt action to notify train crews and other railroads operating over such 

crossing prior to the next train operation over the crossing. Further, the railroad is required to 

notify the law enforcement agency having jurisdiction over such crossing, or the railroad police 

who are capable of responding to control vehicular traffic at the crossing. Finally, the railroad 

must take action to assure that its employees, or a law enforcement agency, provide the required 

alternative means of warning for highway users at the crossing. 

A credible report of a highway-rail grade crossing warning system malfunction is defined in 

§ 234.5 as a report from a railroad employee, law enforcement officer, highway traffic official, 

or other employee of a public agency acting in an official capacity. A warning system 

malfunction is defined in § 234.5 as an activation failure, a partial activation, or a false activation 

of a highway-rail grade crossing warning system. 

When the alternative warning that is provided consists of at least one uniformed law enforcement 

officer, or one uniformed railroad police officer, or an appropriately equipped flagger for each 

direction of highway traffic at the crossing, trains may proceed over the crossing at normal 

speed. If there is not an appropriately equipped flagger for each direction of highway traffic or at 

least one uniformed law enforcement officer or uniformed railroad police officer at the crossing, 

each train may proceed with caution through the crossing at a speed not exceeding 15 mph. A 

train may proceed at normal speed after its locomotive has passed over the crossing. Where a 

shoving movement is involved, a crewmember must be on the ground to flag the train through 

the crossing. 

Note: The appropriately equipped flagger requirements are very narrow in scope in that only in 

the event the flagger(s) is being used as alternative warning to allow train movement through the 

crossing at normal speed do the appropriately equipped provisions apply. 

In lieu of complying with the alternative warning requirements listed above, a railroad may 

temporarily take the warning system out of service if the railroad complies with all requirements 

of § 234.105, “Activation failure.” 

At crossings where it has been determined that the warning system is not functioning as 

intended, § 234.207’s requirement for adjustment, repair, or replacement without undue delay 

applies. 

This section also requires that the locomotive audible warning device be activated in accordance 

with railroad rules when approaching a crossing where a partial activation has been reported. 
234-16 

The reference to railroad rules has to do with the manner in which the horn is sounded. This 

section preempts any State or local “whistle bans” with respect to use of the horn under the 

circumstances addressed in the section. (See Technical Bulletin S-96-08.)

CLASSIFICATION OF DEFECTS

234.106.A1 Train crew or other railroads operating over crossing not notified of partial 

activation prior to arrival of train at crossing. 

234.106.B1 Law enforcement agency having jurisdiction or railroad police not promptly 

notified of partial activation. 

234.106.C1 Alternative means of actively warning highway users not provided at crossing 

where credible report indicates partial activation has occurred. 

234.106.C2 Train passed over crossing at a speed exceeding 15 mph without alternative 

means of warning being provided by the required number of appropriately 

equipped flaggers, a uniformed law enforcement officer, or a uniformed railroad 

police officer. 

234.106.C3 Crewmember not on the ground at the crossing to flag train through the crossing 

in a shoving movement. 

234.106.C4 Flagger not equipped with required vest, shirt, or jacket. 

234.106.C5 Flagger not equipped with required flagging equipment. 

234.106.C6 Warning system taken out of service without complying with the requirements of 

§ 234.105. 

234.106.D1 Locomotive audible warning device not sounded in accordance with the railroad’s 

rules as train approached crossing where partial activation has been identified by 

a credible report. 

§ 234.107 False activation.

 Upon receipt of a credible report of a false activation, a railroad having maintenance 

responsibility for the highway-rail grade crossing warning system shall promptly initiate efforts 

to warn highway users and railroad employees at the crossing by taking the following actions: 

 (a) Prior to a train’s arrival at the crossing, notify the train crew of the report of false 

activation and notify any other railroads operating over the crossing; 

 (b) Notify the law enforcement agency having jurisdiction over the crossing, or railroad 

police capable of responding and controlling vehicular traffic; and 

 (c) Provide for alternative means of actively warning highway users of approaching trains, 

consistent with the following requirements (see Appendix B for a summary chart of alternative 

means of warning): 

 (1)(i) If an appropriately equipped flagger is providing warning for each direction of 

highway traffic, trains may proceed through the crossing at normal speed. 
234-17 

 (ii) If at least one uniformed law enforcement officer (including a railroad police officer) 

provides warning to highway traffic at the crossing, trains may proceed through the crossing at 

normal speed. 

 (2) If there is not an appropriately equipped flagger providing warning for each direction of 

highway traffic, or if there is not at least one uniformed law enforcement officer providing 

warning, trains with the locomotive or cab car leading, may proceed with caution through the 

crossing at a speed not exceeding 15 miles per hour. Normal speed may be resumed after the 

locomotive has passed through the crossing. In the case of a shoving move, a crewmember shall 

be on the ground to flag the train through the crossing. 

 (3) In lieu of complying with paragraphs (c)(1) or (2) of this section, a railroad may 

temporarily take the warning system out of service if the railroad complies with all requirements 

of § 234.105, “Activation failure.” 

 (d) A locomotive’s audible warning device shall be activated in accordance with railroad 

rules regarding the approach to a grade crossing.

Application:

This section requires that a railroad having maintenance responsibility for a warning system take 

prompt action to provide alternative means of warning for highway users and railroad employees 

at a specific crossing where a credible report of a system malfunction involving a false activation 

has been received. This section further requires that specific actions be followed to provide that 

alternative warning. 

When a railroad receives a credible report of a system malfunction involving a false activation, it 

is required to take prompt action to notify train crews and other railroads operating over such 

crossing prior to the next train operation over the crossing. Further, the railroad is also required 

to notify the law enforcement agency having jurisdiction over such crossing, or the railroad 

police who are capable of responding to control vehicular traffic at the crossing. Finally, the 

railroad must take action to assure that its employees, or a law enforcement agency, provide the 

required alternative means of warning for highway users at the crossing. 

A credible report of a highway-rail grade crossing warning system malfunction is defined in 

§ 234.5 as a report from a railroad employee, law enforcement officer, highway traffic official, 

or other employee of a public agency acting in an official capacity. A warning system 

malfunction is defined in § 234.5 as an activation failure, a partial activation, or a false activation 

of a highway-rail grade crossing warning system. 

When the alternative warning that is provided consists of at least one uniformed law enforcement 

officer, or one uniformed railroad police officer, or an appropriately equipped flagger for each 

direction of highway traffic at the crossing, trains may proceed over the crossing at normal 

speed. If there is not an appropriately equipped flagger for each direction of highway traffic or at 

least one uniformed law enforcement officer or uniformed railroad police officer at the crossing, 

each train may proceed with caution through the crossing at a speed not exceeding 15 mph. A 

train may proceed at normal speed after its locomotive has passed over the crossing. Where a 

shoving movement is involved, a crewmember must be on the ground to flag the train through 

the crossing. 

Note: The appropriately equipped flagger requirements are very narrow in scope in that only in 

the event the flagger(s) is being used as alternative warning to allow train movement through the 

crossing at normal speed do the appropriately equipped provisions apply. 
234-18 

In lieu of complying with the alternative warning requirements listed above, a railroad may 

temporarily take the warning system out of service if the railroad complies with all requirements 

of § 234.105, “Activation failure.” 

At crossings where it has been determined that the warning system is not functioning as 

intended, § 234.207’s requirement for adjustment, repair, or replacement without undue delay 

applies. 

This section also requires that the locomotive audible warning device be activated in accordance 

with railroad rules when approaching a crossing where a false activation has been reported. The 

reference to railroad rules has to do with the manner in which the horn is sounded. This section 

preempts any State or local “whistle bans” with respect to use of the horn under the 

circumstances addressed in the section. (See Technical Bulletin S-96-08.)

CLASSIFICATION OF DEFECTS

234.107.A1 Train crew or other railroads operating over crossing not notified of false 

activation prior to arrival of train at crossing. 

234.107.B1 Law enforcement agency having jurisdiction or railroad police not promptly 

notified of false activation. 

234.107.C1 Alternative means of actively warning highway users not provided at crossing 

where credible report indicates false activation has occurred. 

234.107.C2 Train passed over crossing at a speed exceeding 15 mph without alternative 

means of warning being provided by the required number of appropriately 

equipped flaggers, a uniformed law enforcement officer, or a uniformed railroad 

police officer. 

234.107.C3 Crewmember not on the ground at the crossing to flag train through the crossing 

in a shoving movement. 

234.107.C4 Flagger not equipped with required vest, shirt, or jacket. 

234.107.C5 Flagger not equipped with required flagging equipment. 

234.107.C6 Warning system taken out of service without complying with the requirements of 

§ 234.105. 

234.107.D1 Locomotive audible warning device not sounded in accordance with the railroad’s 

rules as train approached crossing where false activation has been identified by a 

credible report. 
234-19 

§ 234.109 Recordkeeping.

 (a) Each railroad shall keep records pertaining to compliance with this subpart. Records 

may be kept on forms provided by the railroad or by electronic means. Each railroad shall keep 

the following information for each credible report of warning system malfunction: 

 (1) Location of crossing (by highway name and DOT/AAR Crossing Inventory Number); 

 (2) Time and date of receipt by railroad of report of malfunction; 

 (3) Actions taken by railroad prior to repair and reactivation of repaired system; and 

 (4) Time and date of repair. 

 (b) Each railroad shall retain for at least one year (from the latest date of railroad activity in 

response to a credible report of malfunction) all records referred to in paragraph (a) of this 

section. Records required to be kept shall be made available to FRA as provided by 49 U.S.C. 

20107 (formerly 208 of the Federal Railroad Safety Act of 1970 (45 U.S.C. 437)).

Application:

This section requires the railroad to keep a record of each credible report of a warning system 

malfunction. This section specifies the information that is to be recorded and that each record 

shall remain on file and available for inspection by the FRA for a period of at least one year from 

the date of the last railroad activity in connection with such report. 

Each railroad is required to keep a record of each credible report of a highway-rail grade crossing 

warning system malfunction. Such record may be kept on a form provided by the railroad or 

electronically. Each record shall contain the following information: 

1. Location of crossing (by highway name and U.S. Department of Transportation 

(DOT)/Association of American Railroads (AAR) crossing inventory number). 

2. Time and date that the railroad received the report. 

3. Action taken by railroad to comply with §§ 234.105, 234.106, or 234.107; (i.e., the 

appropriate train crews being notified, Stop and Flag order issued, proceed with caution 

maximum speed 

15 mph order issued, flaggers at crossing, appropriate law enforcement notified, etc.). 

4. Time and date of action taken to make final repair or correction (explanation of the type 

of repair or correction). If the system is dismantled and removed instead of repaired, the 

date of removal should be recorded. 

Each record of a credible report of a warning system malfunction (i.e., an activation failure, a 

partial activation, or a false activation) shall be kept and made available for inspection by the 

FRA for one year from the last date of action taken on each report. Thus, if the warning system 

is repaired and put back in service, the record shall be kept for one year from the date of the last 

repair to reactivate the system. If the system is dismantled and removed, the record shall be kept 

for one year from the date of the removal. The records required by this section may be kept at 

division offices or at a central location somewhere on the railroad. 
234-20 

CLASSIFICATION OF DEFECTS

234.109.A1 Record not kept of credible report of malfunctioning highway-rail grade crossing 

warning system. 

234.109.A2 Record of credible report of malfunctioning highway-rail grade crossing warning 

system not complete. 

234.109.A3 Record of credible report of malfunctioning highway-rail grade crossing warning 

system not correct. 

234.109.B1 Record of credible report of malfunctioning highway-rail grade crossing warning 

system not kept for at least one year after the last recorded activity in response to 

the report. 

234.109.B2 Record of credible report of malfunctioning highway-rail grade crossing warning 

system not made available to FRA for inspection or replication. 

Subpart D – Maintenance, Inspection, and Testing

Maintenance Standards 

§ 234.201 Location of plans. 

 Plans required for proper maintenance and testing shall be kept at each highway-rail grade 

crossing warning system location. Plans shall be legible and correct.

Application:

Plans are necessary for the proper installation, inspection, maintenance, testing, and repair of 

highway-rail grade crossing warning systems. Such plans are required to be legible and correct. 

Plans shall be kept at each highway-rail grade crossing warning system location. 

Such plans shall include, but are not limited to the following: layout of track, warning devices 

installed, control circuitry, approach lengths, approach circuits, and standby power type and 

capacity. 

While manufacturer’s manuals are not required by this section, specific information necessary 

for the installation setup, inspection, maintenance, testing, and repair of the train detection 

equipment shall be included on the plans or otherwise kept at the location. 

Plans are required to be legible and correct. Plans that are torn, faded, or consisting of more than 

one change in colored pencil are not considered to be legible and/or correct. 

CLASSIFICATION OF DEFECTS

234.201.A1 Plans not kept at crossing location. 
234-21 

234.201.A2 Plans not legible. 

234.201.A3 Plans not correct. 

§ 234.203 Control circuits.

 

 All control circuits that affect the safe operation of a highway-rail grade crossing warning 

system shall operate on the fail-safe principle.

Application:

This section requires that all control circuits that affect the safe operation of a highway-rail grade 

crossing warning system shall operate on the fail-safe principle. 

This section includes all train detection track circuits and control circuits through which a 

highway-rail grade crossing warning system is activated. The fail-safe principle requires that 

such circuits shall operate so that the failure of any part or component shall cause the warning 

system to activate. An example of noncompliance would be a fouling circuit on a switch turnout 

that extends into the crossing island. 

A crossing warning system activated by means other than train detection track circuit may not 

comply with this section. 

CLASSIFICATION OF DEFECTS

234.203.A1 Control circuit that affects the safe operation of a highway-rail grade crossing 

warning system does not operate on the fail-safe principle. 

§ 234.205 Operating Characteristics of Warning System Apparatus. 

 Operating characteristics of electromagnetic, electronic, or electrical apparatus of each 

highway-rail crossing warning system shall be maintained in accordance with the limits within 

which the system is designed to operate. 

Application:

This section requires the operating characteristics of electromagnetic, electronic, or electrical 

apparatus of each highway-rail grade crossing warning system be maintained in accordance with 

the limits within which it is designed to operate. 

Sections 234.247 through 234.271 of this part address those devices that are so important to the 

safety of highway-rail grade crossing warning systems that periodic tests and/or inspections are 

required to determine that their operating characteristics remain acceptable. 

Applies to all electromagnetic, electronic, or electrical devices used in, or associated with, 

highway-rail grade crossing warning systems. 
234-22 

Each railroad should have specifications setting forth the pick-up values, release values, working 

values, and condemning limits of these values for all electromagnetic, electronic, or electrical 

devices in use in highway-rail grade crossing warning systems on their property. 

Some examples of deficient operating characteristics are: 

 Pick-up value too high 

 Pick-up value too low 

 Release value too high 

 Release value too low 

Manufacturer specifications, or railroad standards compatible with manufacturer specifications, 

shall be used to determine the values. 

Some examples of devices covered by this rule but not requiring specific periodic tests are: 

 Electronic train detection devices. 

 Hold-clear devices in gate mechanisms. 

CLASSIFICATION OF DEFECTS

234.205.A1 Pick-up value of electromagnetic device not in accordance with the limits within 

which it is designed to operate. 

234.205.A2 Drop-away value of electromagnetic device not in accordance with the limits 

within which it is designed to operate. 

234.205.A3 Working values of electromagnetic, electronic, or electrical device not in 

accordance with the limits within which the apparatus is designed to operate. 

234.205.A4 Operating characteristics of other electromagnetic, electronic, or electrical device 

not within prescribed limits. 

234.205.A5 Operating characteristics of electromagnetic, electronic, or electrical device not 

maintained in proper operation. 

§ 234.207 Adjustment, repair, or replacement of component.

 (a) When any essential component of a highway-rail grade crossing warning system fails to 

perform its intended function, the cause shall be determined and the faulty component adjusted, 

repaired, or replaced without undue delay. 

 (b) Until repair of an essential component is completed, a railroad shall take appropriate 

action under § 234.105, “Activation failure,” § 234.106, Partial activation, or § 234.107, “False 

activation,” of this part. 

Application:
234-23 

This section requires a railroad to determine the cause of a highway-rail grade crossing active 

warning system failure, malfunction, or defective condition affecting the proper operation and/or 

ability of the system to warn highway users of an approaching train; and perform necessary 

adjustment, repair, or replacement without undue delay. Until such corrective action is 

completed, the railroad shall take, when necessary, the appropriate actions as described in 

§§ 234.105, 234.106, or 234.107. 

A highway-rail grade crossing active warning system failure, malfunction, or defective condition 

means any essential component of such a system failing to perform its intended function. 

A railroad is required to take action to determine the cause of each failure, malfunction, or 

defective condition and complete necessary adjustment, repair, or replacement without undue 

delay. 

Because of the great variety of factors involved with failure, malfunction, or defective conditions 

of warning systems, including the location of the crossing, frequency of train movements, type of 

corrective action needed, availability of personnel, and other competing emergency situations; it 

is not practical to establish specific time limits for remedial actions. FRA continues to believe 

that the requirements of this section, taken together with the alternative protective measures 

required under §§ 234.105, 234.106, and 234.107, will provide the needed measure of safety. 

Therefore, “without undue delay” shall mean in as timely a manner as possible. 

However, because temporary measures involve heightened risk to persons manually controlling 

motor vehicle traffic and other risks (e.g., miscommunication between flaggers at multiple-track 

crossings), it is important that grade crossing warning systems be promptly restored to proper 

functioning. The urgency associated with this need is a product of rail traffic, motor vehicle 

traffic, the configuration of the crossing, and other factors. FRA will expect railroads to restore 

warning systems to proper functioning without delay that is undue in relation to these safety 

considerations and, in general, as soon as possible. (See Technical Bulletin S-96-08)

CLASSIFICATION OF DEFECTS

234.207.A1 No action taken to determine the cause of active warning system failure, 

malfunction, or defective condition affecting the proper operation and/or ability 

of the system to warn highway users of an approaching train. 

234.207.A2 Component causing active warning system failure, malfunction, or defective 

condition affecting the proper operation and/or ability of the system to warn 

highway users of an approaching train, not adjusted without undue delay. 

234.207.A3 Component causing active warning system failure, malfunction, or defective 

condition affecting the proper operation and/or ability of the system to warn 

highway users of an approaching train, not repaired without undue delay. 

234.207.A4 Component causing active warning system failure, malfunction, or defective 

condition affecting the proper operation and/or ability of the system to warn 

highway users of an approaching train, not replaced without undue delay. 
234-24 

234.207.B1 Train operation not in compliance with the applicable §§ 234.105, 234.106, or 

234.107 until corrective action is completed. 

§ 234.209 Interference with normal functioning of system. 

 (a) The normal functioning of any system shall not be interfered with in testing or otherwise 

without first taking measures to provide for safety of highway traffic that depends on normal 

functioning of such system. 

 (b) Interference includes, but is not limited to: 

 (1) Trains, locomotives or other railroad equipment standing within the system's approach 

circuit, other than normal train movements or switching operations, where the warning system is 

not designed to accommodate those activities. 

 (2) Not providing alternative methods of maintaining safety for the highway user while 

testing or performing work on the warning systems or on track and other railroad systems or 

structures which may affect the integrity of the warning system.

Application:

This section requires the railroad to provide for the safety of highway users and/or train traffic 

before interfering, in testing or otherwise, with the normal functioning of any highway-rail grade 

crossing warning system. 

The intent of this section is to ensure that railroads maintain the integrity of crossing warning 

systems by prohibiting procedures or practices which defeat or nullify the normal function of 

such systems. 

Interference is any condition that circumvents, hinders, impedes, or diminishes whatsoever the 

intended warning of a system, and may be accomplished by testing, installing, repairing, 

replacing, operating, or manipulating a warning system component used in detecting the 

presence of or displaying warning of a train, or in indicating the operation of the warning system. 

There is no difference between accidental or intentional interference with respect to the 

enforcement of this section. 

Tests of crossing warning systems must not be conducted until it has been ascertained that 

provisions have been made for the safety of highway users and no train movements will be 

affected. 

Interference includes, but is not limited to: 

1. Trains, locomotives, or other railroad equipment left standing within the warning 

system’s approach circuit, other than normal switching operations, where the system is 

not designed to accommodate those activities. 

2. Not providing alternative methods of maintaining safety for highway users and/or train 

movements while testing or performing work on the warning system, or on track and 

other railroad systems or structures which may affect the integrity of the warning system. 

3. Physically restricting gate arm operation (e.g., tying up or blocking up gate arms). 
234-25 

It shall not be considered interference if a train is standing within a warning system’s approach 

circuit while waiting for a signal indication or other authority for movement. It shall not be 

considered interference, when in the course of normal testing, a shunt placed on the rail causes 

adjacent crossing warning systems to be activated. 

Using manual overrides to activate or deactivate a crossing warning system is not considered 

interference, as long as proper warning is provided to highway users. 

Activation of a warning system during a normal movement through a crossing by on-track 

vehicles is not considered interference with the warning system. Intermittent activations during a 

normal movement through a crossing by on-track vehicles is not considered interference with the 

warning system, provided that the railroad’s operating rules or other instructions provide for 

warning of highway users at the crossing. In general, measures taken for the safety of highway 

users and train traffic should be consistent with those specified in 

§§ 234.105, 234.106, and 234.107 of this part. 

CLASSIFICATION OF DEFECTS

234.209.A1 Interference with normal functioning of warning system without taking measures 

to provide for the safety of highway users and train traffic.

§ 234.211 Security of warning system apparatus. 

 Highway-rail grade crossing warning system apparatus shall be secured against unauthorized 

entry.

Application:

This section requires that all outdoor housings of highway-rail grade crossing warning system 

apparatus be kept locked, sealed, or secured against unauthorized entry. 

This requirement includes warning system cases, light unit housings, gate mechanism housings, 

junction or terminal boxes, battery boxes, bell or audible warning devices, etc. Wrench locking 

or nut-locking with bell is acceptable. 

CLASSIFICATION OF DEFECTS

234.211.A1 Warning system instrument case not secured against unauthorized entry. 

234.211.A2 Other component housing not secured against unauthorized entry. 

§ 234.213 Grounds. 

 Each circuit that affects the proper functioning of a highway-rail grade crossing warning 

system shall be kept free of any ground or combination of grounds that will permit a current flow 

of 75 percent or more of the release value of any relay or electromagnetic device in the circuit. 

This requirement does not apply to: circuits that include track rail; alternating current power 
234-26 

distribution circuits that are grounded in the interest of safety; and common return wires of 

grounded common return single break circuits.

Application:

This section requires that circuits that affect the proper functioning of a highway-rail grade 

crossing warning system are to be kept free of grounds equal to or in excess of 75 percent of the 

release value of any relay or electromagnetic device in the circuit. Track circuits, common 

return wires of grounded common return single break circuits, and alternating current power 

distribution circuits grounded in the interest of safety are excluded. 

 

Crossing control circuits designed to be ground-free are required to be kept free of any ground 

having a current value equal to or in excess of 75 percent of the release value of any relay or 

electromagnetic device in the circuit. Electronic devices designed to be ground free shall be kept 

free of grounds having a value that affects the proper operation of the device. The railroad must 

take prompt action to correct a ground. 

There is no difference between an accidental ground and an intentional ground. 

Extreme care shall be exercised when testing for grounds. Testing shall not be conducted while 

trains are approaching or passing The meter shall be watched at all times. If the meter indicates 

that a relay becomes energized, the meter shall be immediately disconnected. An unobserved 

meter shall never be left connected between a control circuit and ground. 

Ground tests shall be performed at every instrument case or house inspected. The preliminary 

test shall be with a voltmeter connected from line or track arrestor ground to a track circuit which 

will prove the meter is operating and the integrity of the ground circuit. 

Alternating current (AC) power shall be interrupted during tests in order to check AC lighting 

circuits having direct current (DC) standby. (See Technical Bulletin S-99-03)

CLASSIFICATION OF DEFECTS

234.213.A1 Circuit grounded sufficiently to permit flow of current equal to or in excess of 

75 percent of the release value of relay or other electromagnetic device in the 

circuit. 

§ 234.215 Standby power system.

 A standby source of power shall be provided with sufficient capacity to operate the warning 

system for a reasonable length of time during a period of primary power interruption. The 

designated capacity shall be specified on the plans required by § 234.201 of this part.

Application:

This section requires railroads to provide a standby power source to operate the warning system 

for a reasonable length of time during a period of primary power interruption. The designated 

capacity shall be specified on the plans, as required by § 234.201. 
234-27 

The intent of this section is that a railroad is required to install and properly maintain a standby 

power source in order to operate the system for a sufficient length of time during a primary 

power interruption. 

The designated capacity specified on the plans shall include the number and ampere hour rating 

of batteries. 

Determining the capacity of the standby power source will be at the discretion of each individual 

railroad. It is recommended that certain factors should be considered such as: the power 

demands of each particular location (taking into account urban or rural), the likelihood of 

discovery of the primary power outage (i.e., electronic notification devices, power-off indicators, 

employee discovery, etc.), the availability and proximity of maintenance employees, and the 

number of trains that are operated over the crossing. 

THE FOLLOWING ARE SCENARIOS OF SEVERAL APPLICATIONS OF THIS SECTION: 

1. A primary power interruption unknown to and beyond the control of the railroad (e.g., 

blown fuses and opened circuit breakers at commercial power) and: 

a. During which the standby power source operated as designed, discovery of the power 

interruption was made and primary power was restored, or the standby power source 

became depleted but alternative warning was provided as required in § 234.105; no 

violation is warranted. 

b. If discovery of the power interruption does not occur before the properly maintained 

standby power source becomes depleted and an activation failure does occur, no 

violation is warranted. 

c. If discovery of the power interruption occurs after depletion of standby power, and 

alternative warning or other power source is not promptly provided, a violation of 

§ 234.105 will normally be warranted. 

d. If the standby power source fails to operate to its designed capacity, a violation has 

occurred and consideration should be given to assessment of a civil penalty. 

2. A primary power interruption within control of the railroad (e.g., one caused by a 

defective condition of railroad power line wires, improper grounding, or power left 

manually interrupted) has occurred and: 

a. If discovery of the power interruption occurs and alternative warning is provided, 

other power source is provided, or power is restored, a violation is not warranted. 

b. It results in the standby power source becoming depleted and an activation failure 

occurs, a violation of this section is warranted. 

CLASSIFICATION OF DEFECTS

234.215.A1 Standby power source not provided. 

234.215.A2 Standby power source not of sufficient capacity to operate highway-rail grade 

crossing warning system during an interruption of the primary source of power. 
234-28 

234.215.A3 Standby power source not maintained to provide sufficient capacity to operate 

highway-rail grade crossing warning system during an interruption of the primary 

source of power. 

234.215.A4 Designated capacity of standby power source not specified on plans.

§ 234.217 Flashing light unit. 

 (a) Each flashing light unit shall be properly positioned and aligned and shall be visible to a 

highway user approaching the crossing. 

 (b) Each flashing light unit shall be maintained to prevent dust and moisture from entering 

the interior of the unit. Roundels and reflectors shall be clean and in good condition. 

 (c) All light units shall flash alternately. The number of flashes per minute for each light 

unit shall be 35 minimum and 65 maximum.

Application:

This section requires that each flashing light unit be properly positioned and aligned, and be 

visible to a highway user approaching the crossing. Each flashing light unit shall be maintained 

to prevent dust and moisture from entering the interior of the unit. Roundels and reflectors shall 

be clean and in good condition. All light units shall flash alternately and the number of flashes 

per minute shall not be less than 35 nor more than 65. 

The intent of this section, in part, is that at a minimum, flashing lights are expected to be visible 

to approaching highway users. Federal and State inspectors should normally defer to the 

judgment of the signal maintainer if that individual is acting in a manner consistent with 

established railroad policy or practice. 

CLASSIFICATION OF DEFECTS

234.217.A1 Flashing light not visible to approaching highway user. 

234.217.B1 Flashing light unit not maintained to prevent dust or moisture from entering the 

unit. 

234.217.B2 Roundels or reflectors not maintained in good condition. 

234.217.C1 Flashing lights do not flash alternately. 

234.217.C2 Flash rate less than 35 times per minute. 

234.217.C3 Flash rate more than 65 times per minute. 

§ 234.219 Gate arm lights and light cables.

 Each gate arm light shall be maintained in such condition to be properly visible to 

approaching highway users. Lights and light wire shall be secured to the gate arm.

Application: 
234-29 

This section requires that each gate arm light be maintained so that it is properly visible to 

approaching highway users. It also requires that lights and light wire be secured to the gate arm. 

This section applies to gate arm lights and light wires installed at active warning systems. Each 

gate arm light shall be visible to approaching highway users and pedestrians, if applicable. This 

section also requires that lights and light wires be securely fastened to each gate arm. The intent 

of this section is that lights and light wires shall be maintained in accordance with design 

specifications. 

CLASSIFICATION OF DEFECTS

234.219.A1 Gate arm light burned out or missing. 

234.219.A2 Gate arm light unit defective, not visible, or missing. 

234.219.A3 Light unit not securely fastened to gate arm. 

234.219.A4 Light wires not securely fastened to gate arm. 

 

234.219.A5 Gate arm light unit not maintained per design specifications. 

§ 234.221 Lamp Voltage. 

 The voltage at each lamp shall be maintained at not less than 85 percent of the prescribed 

rating for the lamp.

Application: 

This section requires that the voltage at each lamp shall be maintained at not less than 85 percent 

of the prescribed lamp rating. 

Gate arm lights are not subject to periodic testing requirements, however, if there is a question 

regarding gate arm light visibility (§ 234.219), a Federal or State inspector may request that 

voltage be verified by an appropriate test. When there is a need for gate arm lamp voltage to be 

verified, the voltage should normally be tested at the gate mechanism or suitable junction box. 

When the test is conducted with primary power removed, the lights should operate for not less 

than two minutes and not more than five minutes before lamp voltage readings are taken. See § 

234.253 for testing procedures for flashing light units. (See Technical Bulletin S-96-07)

CLASSIFICATION OF DEFECTS

234.221.A1 Lamp voltage on primary power less than 85 percent of prescribed lamp rating. 

234.221.A2 Lamp voltage on standby power less than 85 percent of prescribed lamp rating. 
234-30 

§ 234.223 Gate Arm. 

 Each gate arm, when in the downward position, shall extend across each lane of approaching 

highway traffic and shall be maintained in a condition sufficient to be clearly viewed by 

approaching highway users. Each gate arm shall start its downward motion not less than three 

seconds after flashing lights begin to operate and shall assume the horizontal position at least 

five seconds before the arrival of any normal train movement through the crossing. At those 

crossings equipped with four quadrant gates, the timing requirements of this section apply to 

entrance gates only.

Application: 

This section requires that each gate arm, when in the horizontal position, extend across each lane 

of approaching highway traffic and be maintained in a condition sufficient to be clearly viewed 

by approaching highway users. Each gate arm shall start its downward motion not less than 3 

seconds after flashing lights begin to operate and assume the horizontal position at least 5 

seconds before the arrival of any normal train movement through the crossing.

The required length of each gate arm is determined by the design length as indicated on the 

circuit plans. In the absence of a design length, the gate arm must extend across at least 90 

percent of each lane of approaching highway traffic. 

The “5 seconds” provision applies to the design and maintenance of warning systems to ensure 

the gates are horizontal for the normal operation of through trains. Switching movements that 

occupy grade crossings, or trains that stop short of grade crossings and then occupy such grade 

crossings after the warning system has timed out, must operate according to railroad operating 

rules or special instructions. When there is no conflicting highway traffic, such movements are 

not required to wait 5 seconds. 

Trains operating over “island circuit only” installations must operate in accordance with 

operating rules which ensure the gates are down and safety is provided for highway users. 

As information, the Manual on Uniform Traffic Control Devices (MUTCD) recommends that the 

gate arm will not be less than 3 feet 6 inches, nor more than 4 feet 6 inches, measured from the 

crown of the highway surface, when the gate arm is in the full horizontal position. It further 

recommends that, at a minimum, the gate arm shall be equipped with at least three red lights and 

when activated, the gate arm light nearest the tip shall be illuminated continuously and the other 

two lights shall flash alternately in unison with the flashing light signals. 

CLASSIFICATION OF DEFECTS

234.223.A1 When horizontal, gate arm does not sufficiently extend across each lane of 

approaching highway traffic. 

234.223.A2 Gate arm not maintained in a condition to be clearly viewed by approaching 

highway users. 

234.223.A3 Gate arm starts its downward motion less than 3 seconds after flashing lights 

begin to operate. 
234-31 

234.223.A4 Gate arm not in horizontal position at least 5 seconds (when required) prior to 

arrival of a train at the crossing. 

234.223.A5 Gate arm not in horizontal position. 

234.223.A6 Gate arm broken or missing. 

§ 234.225 Activation of warning system. 

 A highway-rail grade crossing warning system shall be maintained to activate in accordance 

with the design of the warning system, but in no event shall it provide less than 20 seconds 

warning time for the normal operation of through trains before the grade crossing is occupied by 

rail traffic.

Application: 

This section requires that each highway-rail grade crossing warning system be maintained to 

activate in accordance with the design of the warning system, but in no event shall it provide less 

than 20 seconds warning time for the normal operation of through train movements before the 

crossing is occupied by rail traffic. 

Both the intended warning time and the “20 seconds” provision applies to the design and 

maintenance of warning systems to provide warning for the normal operation of through trains. 

Switching movements that occupy grade crossings, or trains that stop short of grade crossings 

and then occupy such grade crossings after the warning system has timed out, must operate 

according to railroad operating rules or special instructions. When there is no conflicting 

highway traffic, such movements are not required to wait 20 seconds. 

Trains operating over “island only” installations must operate in accordance with operating rules 

which ensure the system is operating in a safe manner for highway users. 

Rail traffic is considered to be equipment designed to activate the crossing warning system. A 

highway-rail grade crossing is considered to be occupied when rail traffic enters the highway-rail 

intersection. (See Technical Bulletin S-08-02)

Note: Defect 234.225.A1 applies to instances where the system warning time differs 

significantly from the designed warning time. 

CLASSIFICATION OF DEFECTS

234.225.A1 Crossing warning time not in accordance with the design of the warning system. 

234.225.A2 Crossing warning system does not provide at least 20 seconds warning time. 

§ 234.227 Train detection apparatus. 

 (a) Train detection apparatus shall be maintained to detect a train or railcar in any part of a 

train detection circuit, in accordance with the design of the warning system. 
234-32 

 (b) If the presence of sand, rust, dirt, grease, or other foreign matter is known to prevent 

effective shunting, a railroad shall take appropriate action under § 234.105, “Activation failure,” 

to safeguard highway users.

Application: 

This section requires that train detection apparatus be maintained to detect a train, locomotive, or 

car which occupies any part of a train detection circuit, in accordance with the design of the 

warning system. It shall not be a violation if the presence of sand, rust, dirt, grease, or other 

foreign matter prevents effective shunting. When these conditions are known to exist, a railroad 

shall take appropriate action as required by § 234.105. The alternative protection provided by § 

234.105 is meant to be a temporary measure since conditions affecting effective shunting must 

be corrected without undue delay as required by § 234.207. 

For purposes of this section, a train detection circuit is a DC, AC, or audio frequency track 

circuit, or a track circuit associated with a motion sensing device or constant warning time device 

that is used to detect the presence and/or motion of a train, locomotive, or car. For DC, AC, or 

audio frequency track circuits, the active portion of the train detection circuit includes all the 

trackage between the ends of the track circuit. For motion-sensing devices or constant warning 

time devices, the active portion of the train detection circuit includes all the trackage between the 

crossing and the point where the device is designed to activate the warning system. 

When crossing circuit plans show standby/backup train detection equipment installed at the 

crossing, such equipment shall be operational and function as intended. 

CLASSIFICATION OF DEFECTS

234.227.A1 Train detection apparatus does not detect a train, locomotive, or car occupying 

any part of the designed limits of the train detection circuit. 

234.227.B1 Adequate measures to safeguard highway users and train operation not taken 

when it is known that a condition of sand, rust, dirt, grease, or other foreign 

matter exists that has prevented effective shunting of a train detection circuit 

when occupied by a train, locomotive, or car. 

§ 234.229 Shunting sensitivity.

 Each highway-rail grade crossing train detection circuit shall detect the application of a shunt 

of 0.06 ohm resistance when the shunt is connected across the track rails of any part of the 

circuit.

Application: 

This section requires that each highway-rail grade crossing train detection circuit shall detect the 

application of a 0.06 ohm resistance shunt when the shunt is connected across any part of the 

track rails of the train detection circuit. 
234-33 

Detection may or may not include activation of the warning system with a 0.06 ohm resistance 

shunt applied to the approach circuit(s). Detection shall include continuous activation of the 

warning system with a 0.06 ohm resistance shunt applied to any part of the island circuit(s). This 

section applies to all train detection circuits that utilize the track rails as part of the detection 

circuit. 

For purposes of this section, a train detection circuit is a DC, AC, or audio frequency track 

circuit, track circuit associated with a motion sensing device, or constant warning time device 

that is used to detect the presence and/or motion of a train, engine, or car. For DC, AC, or audio 

frequency track circuits, the active portion of the train detection circuit includes all the track 

between the ends of the track circuit. For motion-sensing devices or constant warning time 

devices, the active portion of the train detection circuit includes all the trackage between the 

crossing and the point where the device is designed to activate the warning system. 

CLASSIFICATION OF DEFECTS

234.229.A1 Train detection circuit does not detect the application of a shunt of 0.06 ohms 

resistance when the shunt is connected across the track rails of the circuit. 

§ 234.231 Fouling wires.

 Each set of fouling wires in a highway-rail grade crossing train detection circuit shall consist 

of at least two discrete conductors. Each conductor shall be of sufficient conductivity and shall 

be maintained in such condition to ensure proper operation of the train detection apparatus when 

the train detection circuit is shunted. Installation of a single duplex wire with single plug acting 

as fouling wires is prohibited. Existing installations having single duplex wires with a single 

plug for fouling wires may be continued in use until they require repair or replacement. 

Application: 

This section requires that when a switch turnout located within a highway-rail grade crossing 

train detection circuit is equipped with fouling wires, those wires shall consist of two discrete 

conductors, and each conductor shall be of sufficient conductivity and maintained in such 

condition to ensure proper operation of the train detection circuit as required in § 234.227. 

This section applies only to installations where parallel fouling circuits are utilized as part of the 

highway-rail grade crossing warning system. 

The installation of a single duplex wire with single plug as fouling wires is prohibited. The 

single plug constitutes a single conductor. Existing installations having single duplex wires with 

single plug for fouling wires may be continued in use until such time as they require repair or 

replacement. 

Fouling circuits shall be maintained with the requirement of two fouling wires at the heel of the 

reverse switch point, toe, and heel of the switch frog, and between the outer rails of the main 

track and turnout. 

CLASSIFICATION OF DEFECTS
234-34 

234.231.A1 Fouling wires do not consist of at least two discrete conductors. 

234.231.A2 Fouling wires not of sufficient conductivity to detect occupancy when train 

detection circuit is shunted. 

234.231.A3 Fouling wires not maintained in such condition to detect occupancy when train 

detection circuit is shunted. 

§ 234.233 Rail joints. 

 Each non-insulated rail joint located within the limits of a highway-rail grade crossing train 

detection circuit shall be bonded by means other than joint bars and the bonds shall be 

maintained in such condition to ensure electrical conductivity.

Application: 

This section requires that each non-insulated rail joint located within the limits of a highway-rail 

grade crossing train detection circuit be bonded by means other than joint bars and that the bonds 

be maintained in such condition to ensure electrical conductivity. 

CLASSIFICATION OF DEFECTS

234.233.A1 Non-insulated rail joint located within the limits of highway-rail grade crossing 

train detection circuit not bonded to ensure electrical conductivity. 

§ 234.235 Insulated rail joints. 

 Each insulated rail joint used to separate train detection circuits of a highway-rail grade 

crossing warning system shall be maintained to prevent current from flowing between rails 

separated by the insulation in an amount sufficient to cause a failure of the train detection circuit.

Application: 

This section requires that each insulated rail joint used in train detection circuits of a highwayrail grade crossing warning system be maintained to prevent current from flowing between the 

rails separated by the insulation, in an amount sufficient to cause a failure of any train detection 

circuit. 

CLASSIFICATION OF DEFECTS

234.235.A1 Insulated rail joint not maintained in condition to prevent current from flowing 

between rails separated by the insulation, in an amount sufficient to cause a 

failure of any train detection circuit. 

234.235.A2 Insulation in insulated rail joint in bad condition. 
234-35 

§ 234.237 Reverse switch cut-out circuit.

 A switch, when equipped with a switch circuit controller connected to the point and 

interconnected with warning system circuitry, shall be maintained so that the warning system can 

only be cut out when the switch point is within one-half inch of full reverse position.

Application: 

This section requires that when a switch is equipped with a switch circuit controller connected to 

the point and interconnected with highway-rail grade crossing warning system circuitry, such 

switch circuit controller shall be maintained so the warning system can be cut out only when the 

switch point is within one-half inch of the full reverse position. 

Tests shall be made by placing an appropriate gauge between the reverse switch point and rail, 6 

inches from the end of the point, and applying pressure against the gauge until it cannot be 

removed. 

Normally open contacts shall be open at least one-sixteenth inch. The one-sixteenth inch 

requirement applies to reverse contacts when the switch is in the full normal position, or the 

normal contacts when the switch is in full reverse position. 

This section applies specifically to highway-rail grade crossing reverse switch position cut-out 

circuits using switch circuit controllers. The switch circuit controller shall be securely fastened 

in place with its connections also securely fastened. 

CLASSIFICATION OF DEFECTS

234.237.A1 Switch circuit controller contacts on hand-operated switch adjusted to cut out 

warning system when reverse switch point is open more than one-half inch. 

234.237.A2 Contact opening of switch circuit controller contact less than one-sixteenth inch. 

234.237.A3 Switch circuit controller not securely fastened in place. 

234.237.A4 Switch circuit controller connections not securely fastened. 

§ 234.239 Tagging of wires and interference of wires or tags with signal apparatus. 

 Each wire shall be tagged or otherwise so marked that it can be identified at each terminal. 

Tags and other marks of identification shall be made of insulating material and so arranged that 

tags and wires do not interfere with moving parts of the apparatus. This requirement applies to 

each wire at each terminal in all housings including switch circuit controllers and terminal or 

junction boxes. This requirement does not apply to flashing light units, gate arm light units, and 

other auxiliary light units. The local wiring on a solid state crossing controller rack does not 

require tags if the wiring is an integral part of the solid state equipment. 

Application: 
234-36 

This section requires that each wire be tagged or otherwise marked that it can be identified at 

each terminal. Tags and other marks of identification shall be made of insulating material and so 

arranged that tags and wires do not interfere with moving parts of apparatus. 

This section applies to each wire, at each terminal, in all housings, including switch circuit 

controllers and terminal or junction boxes. This requirement does not apply to flashing light 

units, gate arm light units, and other auxiliary light units. 

Wiring shall be tagged or otherwise marked at a terminal. A terminal is any point where the wire 

terminates from its point of origin to and including the point of final termination. The wire may 

be tagged or marked in any manner so that it can be identified. All tag and wire identification 

shall correspond with the circuit plan. If it is necessary to pull the wire to identify it, the railroad 

is in noncompliance. 

The local wiring on a solid state crossing controller rack will not require tags, as long as the 

wiring is an integral part of the solid state equipment. 

CLASSIFICATION OF DEFECTS

234.239.A1 Wire not tagged or otherwise marked so that it can be identified at terminal. 

234.239.A2 Nomenclature of tag or wire identification does not correspond to that of the 

circuit plan. 

234.239.A3 Tag interferes with moving parts of apparatus. 

234.239.A4 Wire interferes with moving parts of apparatus. 

234.239.A5 Tag or other mark of identification in instrument case or apparatus housing not 

made of insulating material.

§ 234.241 Protection of insulated wire; splice in underground wire.

 Insulated wire shall be protected from mechanical injury. The insulation shall not be 

punctured for test purposes. A splice in underground wire shall have insulation resistance at 

least equal to that of the wire spliced. 

Application: 

This section requires that insulated wire be protected from mechanical injury. The insulation 

shall not be punctured for test purposes. A splice in underground wire shall have insulation 

resistance at least equal to that of the wire spliced. 

Insulated wire shall be placed in wire runs, strung on pole line or messenger, buried, or otherwise 

protected in a manner that it cannot be damaged by the operation of apparatus, vehicles, tools, 

workers, or by the opening or closing of doors. No insulated wire or conductor, whether in 

housing or outside, shall be punctured for test purposes. Temporary installation of cable or wires 

on top of the ground must be made permanent as soon as practical. 
234-37 

CLASSIFICATION OF DEFECTS

234.241.A1 Insulated wire not protected from mechanical injury. 

234.241.A2 Insulation of insulated wire punctured for test purposes. 

234.241.A3 Splice in underground wire does not have insulation resistance value at least 

equal to that of the wire spliced. 

§ 234.243 Wire on pole line and aerial cable.

 Wire on a pole line shall be securely attached to an insulator that is properly fastened to a 

cross arm or bracket supported by a pole or other support. Wire shall not interfere with, or be 

interfered with by, other wires on the pole line. Aerial cable shall be supported by messenger 

wire. An open-wire transmission line operating at voltage of 750 volts or more shall be placed 

not less than 4 feet above the nearest cross arm carrying active warning system circuits.

Application: 

This section requires that all wires be securely tied on insulators that are properly fastened to a 

crossarm or bracket attached to a pole or fixture. Wires are required to be maintained clear of all 

other wires. 

Open-wire transmission lines of 750 volts or more must be placed at least 4 feet above the 

nearest crossarm carrying highway-rail grade crossing control circuits. 

This section applies to all wires that affect the proper operation of highway-rail grade crossing 

warning systems, including AC power supply carried on pole line. 

Particular attention should be given to vertical runs of cable. These are frequently found tied off 

at the top of the run, at which point the entire weight of the cable is self-supported. The cable is 

required to be supported throughout by messenger. 

CLASSIFICATION OF DEFECTS

234.243.A1 Wire carried on pole line not securely tied on insulator. 

234.243.A2 Wire not secured because of broken, missing, or burnt pole. 

234.243.A3 Wire not secured because of broken, missing, or burnt crossarm. 

234.243.A4 Wire interferes with or is interfered with by another wire. 

234.243.A5 Cable used aerially not supported on insulators or by messenger. 

234.243.A6 Open wire transmission lines operating at 750 volts or more, less than 4 feet 

above nearest crossarm carrying highway-rail grade crossing control circuits. 
234-38 

§ 234.245 Signs. 

 Each sign mounted on a highway-rail grade crossing signal post shall be maintained in good 

condition and be visible to the highway user. 

Application: 

This section requires that each sign mounted on a highway-rail grade crossing signal post or mast 

be maintained in good condition and be visible to the highway user. 

This section applies to any sign that is attached to a signal pole located at a highway-rail grade 

crossing and is associated with warning highway motorists. (See Technical Bulletin S-96-09)

CLASSIFICATION OF DEFECTS

234.245.A1 Sign not clearly visible to highway user. 

234.245.A2 Sign not in good condition. 

234.245.A3 Sign missing or not secure. 

Inspections and Tests 

§ 234.247 Purpose of inspections and tests; removal from service of relay or device 

 failing to meet test requirements. 

 (a) The inspections and tests set forth in §§ 234.249 through 234.271 are required at 

highway-rail grade crossings located on in service railroad tracks and shall be made to determine 

if the warning system and its component parts are maintained in a condition to perform their 

intended function. 

 (b) If a railroad elects not to comply with the requirements of §§ 234.249 through 234.271 

because all tracks over the grade crossing are out of service or the railroad suspends operations 

during a portion of the year, and the grade crossing warning system is also temporarily taken out 

of service, a full inspection and all required tests must be successfully completed before railroad 

operations over the grade crossing resume. 

 (c) Any electronic device, relay, or other electromagnetic device that fails to meet the 

requirements of tests required by this part shall be removed from service and shall not be 

restored to service until its operating characteristics are in accordance with the limits within 

which such device or relay is designed to operate.

Application: 

This section requires that the inspections and tests set forth in §§ 234.249 through 234.271 are 

required at highway-rail grade crossings with active warning systems located on in-service 

railroad tracks, and shall be made to determine if the warning system and its component parts are 

maintained in a condition to perform their intended function. 

If a railroad elects not to comply with the requirements of these sections because all tracks over 

the grade crossing are out of service or the railroad suspends operations during a portion of the 
234-39 

year, and the grade crossing warning system is also temporarily taken out of service, a full 

inspection and all required tests must be successfully completed before railroad operations over 

the grade crossing resume. 

Any electronic device, relay, or other electromagnetic device that fails to meet the requirements 

of tests required by this part shall be removed from service and shall not be restored to service 

until its operating characteristics are in accordance with the limits within which such device or 

relay is designed to operate. 

The purpose of inspections and tests is to determine if operating characteristics of electronic 

devices, relays, or other electromagnetic devices are within specified values and that apparatus 

and equipment are being maintained in a condition to assure proper operation of warning systems 

at highway-rail grade crossings. 

A railroad may elect not to comply with the requirements of these sections if tracks over the 

grade crossing are out of service or the railroad suspends operations during a portion of the year, 

and the grade crossing warning system is also temporarily taken out of service. A full inspection 

and all required tests must be successfully completed before railroad operations over the grade 

crossing resume. 

CLASSIFICATION OF DEFECTS

234.247.A1 Required inspections and tests not made on highway-rail grade crossing located 

on in-service track. 

234.247.B1 Required inspections and tests not made on highway-rail grade crossing located 

on track temporarily out of service with railroad operations suspended, prior to 

operations resuming. 

234.247.C1 Electronic device, relay, or other electromagnetic device that fails to meet the 

requirements of specified tests not removed from service. 

234.247.C2 Electronic device, relay, or other electromagnetic device that fails to meet 

requirements of specified tests restored to service with operating characteristics 

not in accordance with limits within which it is designed to operate. 

§ 234.249 Ground tests.

 A test for grounds on each energy bus furnishing power to circuits that affect the safety of 

warning system operation shall be made when such energy bus is placed in service and at least 

once each month thereafter.

Application: 

This section requires a test for grounds on each energy bus furnishing power to circuits that 

affect the safety of highway-rail grade crossing warning system operation. The test shall be 

made when such energy bus is placed in service and at least once each month thereafter. 
234-40 

Ground tests are not required to be made on track circuit wires, AC distribution circuits grounded 

in the interest of safety, or common return wires of grounded common single break circuits. At 

some locations it may be necessary to remove the primary power when testing. 

Use of an appropriate external battery source is an acceptable means of testing. 

Tests shall be made by measuring the voltage potential between each energy bus and a point 

known to be grounded with the warning system activated. Warning system activation is not 

necessary when each warning system circuit is tested with an external battery supply. If a 

voltage potential is detected between energy bus and the ground, a current reading shall be taken 

to determine whether the ground is in excess of that permitted by § 234.213. In no case shall a 

reading be taken when a train is approaching closely or passing, nor shall a meter connected 

between an energy bus and the ground be left unattended. 

Tests shall be applied to each output circuit of those electronic devices installed to provide one or 

more individual isolated power supplies from a single common storage battery or power supply. 

(See Technical Bulletin S-99-03)

CLASSIFICATION OF DEFECTS

234.249.A1 Ground test not made on each energy bus furnishing power to circuits that affect 

the safety of warning system operation when such energy bus is placed in service 

and at least once each month thereafter. 

§ 234.251 Standby Power

 Standby power shall be tested at least once each month.

Application: 

This section requires that standby power be tested at least once each month to determine its 

capability to operate the warning system in instances of primary power interruption. (See 

Technical Bulletin S-04-01) 

CLASSIFICATION OF DEFECTS

234.251.A1 Standby power not tested at least once each month. 

§ 234.253 Flashing light units and lamp voltage.

 (a) Each flashing light unit shall be inspected when installed and at least once every twelve 

months for proper alignment and frequency of flashes in accordance with installation 

specifications. 

 (b) Lamp voltage shall be tested when installed and at least once every 12 months thereafter. 

 (c) Each flashing light unit shall be inspected for proper visibility, dirt, and damage to 

roundels and reflectors at least once each month.
234-41 

Application: 

This section requires that each flashing light unit be inspected when installed and at least once 

every 12 months for proper alignment and frequency of flashes in accordance with installation 

specifications. Lamp voltage is required to be tested when the system is installed and at least 

once every 12 months thereafter. Each flashing light unit shall be inspected for proper visibility, 

dirt, and damage to roundels and reflectors at least once each month. A visual external 

inspection of the flashing light unit is an acceptable means of compliance. 

Part of this section requires lamp voltage to be tested when the system is installed and at least 

once every 12 months thereafter. Measuring lamp voltage at the base of a mast is an acceptable 

means for the railroad to perform the test on an annual basis, provided the railroad can determine 

85 percent of the rated voltage at the lamp. However, FRA inspectors or State inspectors can 

observe a flashing light unit voltage test at any point in the system to determine compliance with 

§ 234.221. When there is a need for gate arm lamp voltage to be verified, the voltage 

measurement will normally be tested at the gate mechanism or suitable junction box. 

It is acceptable for railroads to test lamp voltage with primary power applied or with standby 

power applied if they elect to do so. However, FRA inspectors or State inspectors can observe 

tests of lamp voltage with primary power or standby power applied, for compliance with § 

234.221. This section does not require periodic testing of gate arm lights. 

When the test is conducted with primary power removed, the lights should operate for no less 

than 2 minutes and not more than 5 minutes before lamp voltage readings are taken. 

CLASSIFICATION OF DEFECTS

234.253.A1 Each flashing light unit not inspected for alignment and frequency of flashes 

when installed and at least once every 12 months thereafter. 

234.253.B1 Lamp voltage not tested when system is installed and at least once every 12 

months thereafter. 

234.253.C1 Each flashing light unit not inspected for proper visibility, dirt, and damage to 

roundels and reflectors at least once each month. 

§ 234.255 Gate arm and gate mechanism. 

 (a) Each gate arm and gate mechanism shall be inspected at least once each month. 

(b) Gate arm movement shall be observed for proper operation at least once each month. 

 (c) Hold-clear devices shall be tested for proper operation at least once every 12 months.

Application: 

This section requires that each gate arm and gate mechanism be inspected at least once each 

month to determine compliance with § 234.223. Gate arm movement shall be observed for 

proper operation at least once each month. Hold-clear devices shall be tested for proper 

operation at least once every 12 months. 
234-42 

Hold-clear devices are not required to be tested for operating values. An observation of the holdclear device to ensure that it is functioning properly is an acceptable means of testing. 

CLASSIFICATION OF DEFECTS

234.255.A1 Gate arm and gate mechanism not inspected at least once each month. 

234.255.B1 Gate arm movement not observed for proper operation at least once each month. 

234.255.C1 Hold-clear device not tested for proper operation at least once every 12 months.

§ 234.257 Warning system operation. 

 (a) Each highway-rail crossing warning system shall be tested to determine that it functions 

as intended when it is placed in service. Thereafter, it shall be tested at least once each month 

and whenever modified or disarranged. 

 (b) Warning bells or other stationary audible warning devices shall be tested when installed 

to determine that they function as intended. Thereafter, they shall be tested at least once each 

month and whenever modified or disarranged. 

Application: 

This section requires that each highway-rail grade crossing warning system be tested for proper 

operation when the warning system is placed in service and at least once each month thereafter, 

and whenever modified or disarranged. 

 

When a warning bell or other stationary audible warning device is used, it shall be tested for 

proper operation when placed in service. Thereafter it must be tested at least once each month 

and whenever modified or disarranged. 

“Disarranged” includes, but is not limited to, situations in which a relay, circuit board, 

termination shunt, joint bypass coupler, or other electronic device is replaced with another; two 

or more conductors in a cable are severed; a cable or conductor in a warning system is replaced 

with another; or wires are removed at the same time from more than one terminal of a relay, 

electronic device, terminal board, or other vital component of a warning system. The extent of 

testing the warning system for proper operation will be dependent on the degree of modification 

or disarrangement. The use of a test switch or similar device is permissible while performing a 

routine test at least once each month. (See Technical Bulletin S-96-10)

CLASSIFICATION OF DEFECTS

234.257.A1 Highway-rail grade crossing warning system not tested to determine that it 

functions as intended when placed in service or when modified or disarranged. 

234.257.A2 Highway-rail grade crossing warning system not tested at least once each month 

to determine that it functions as intended. 

234.257.B1 Warning bell or other stationary audible warning device not tested when placed in 

service or when modified or disarranged. 
234-43 

234.257.B2 Warning bell or other stationary audible warning device not tested at least once 

each month. 

§ 234.259 Warning time.

 Each crossing warning system shall be tested for the prescribed warning time at least once 

every 12 months and when the warning system is modified because of a change in train speeds. 

Electronic devices that accurately determine actual warning time may be used in performing 

such tests.

Application: 

This section requires that each highway-rail grade crossing warning system be tested for the 

prescribed warning time at least once every 12 months and when the warning system is modified 

because of a change in train speeds. 

Testing can be accomplished by observation of a train movement, if practical, by calculation and 

track shunt simulation of a train movement, or by use of an electronic device that accurately 

determines warning time. 

If calculation and track shunt simulation of a train movement is not practical for testing constant 

warning time devices and motion detection devices, observation of a train movement or use of an 

electronic device that accurately determines warning time can be used. 

The calculation method would require that the maximum train speed be converted from mph to 

feet per second. The resulting feet per second train speed would then be multiplied by the 

number of seconds of the prescribed warning time. This product would then represent a point, in 

feet, of a minimum distance from the edge of the grade crossing where train detection by the 

warning system must occur to assure adequate warning time. A shunt must then be placed at that 

point to ensure that the system detects the presence of the shunt. 

This section applies to all equipment (including standby units, if equipped) used in each 

highway-rail grade crossing warning system. (See Technical Bulletin S-08-02)

CLASSIFICATION OF DEFECTS

234.259.A1 Crossing warning system not tested for the prescribed warning time at least once 

every 12 months. 

234.259.A2 Crossing warning system not tested for the prescribed warning time when 

warning system is modified because of a change in train speeds. 

§ 234.261 Highway traffic signal pre-emption. 

 Highway traffic signal pre-emption interconnections, for which a railroad has maintenance 

responsibility, shall be tested at least once each month.

Application: 
234-44 

This section requires that highway traffic signal pre-emption interconnections, for which a 

railroad has maintenance responsibility, be tested at least once each month. (See Technical 

Bulletin S-04-01)

The pre-emption of a highway traffic signal requires an electrical circuit between the control 

device of the crossing warning system and the controller assembly of the highway traffic signal. 

The railroad will only be responsible for the maintenance and testing of its interconnections. 

CLASSIFICATION OF DEFECTS

234.261.A1 Highway traffic signal pre-emption interconnections, for which a railroad has 

maintenance responsibility, not tested at least once each month. 

§ 234.263 Relays. 

 (a) Except as stated in paragraph (b) of this section, each relay that affects the proper 

functioning of a crossing warning system shall be tested at least once every four years. 

 (b)(1) Alternating current vane type relays, direct current polar type relays, and relays with 

soft iron magnetic structure shall be tested at least once every two years. 

 (2) Alternating current centrifugal type relays shall be tested at least once every 12 months. 

 (c) Testing of relays requiring testing on four year intervals shall be completed in 

accordance with the following schedule: 

 (1) Not less than 50% by the end of calendar year 1996; 

 (2) Not less than a total of 75% by the end of calendar year 1997; and 

 (3) One hundred percent by the end of calendar year 1998. 

 (d) Testing of relays requiring testing on two year intervals shall be completed by the end of 

calendar year 1996.

Application: 

This section requires that each relay which affects the proper functioning of a crossing warning 

system shall be tested at least once every 4 years, except: 

1. Alternating current vane type relays, direct current polar type relays, and relays with soft 

iron magnetic structure, shall be tested at least once every 2 years. 

2. Alternating current centrifugal type relays shall be tested at least once every 12 months. 

This section applies to in-service relays used in vital circuits of highway-rail grade crossing 

warning systems. Such relays include power off (POR) or power transfer relays (PTR), and 

flasher relays (FLR). It does not apply to miniature non-vital relays or motor control and gate 

mechanism relays. 

This section is applicable only to relays in service. A relay, after being tested or repaired, is not 

considered in service until it is installed in a warning system. 

Use of an “in-service” relay that has broken glass, high resistance contacts, burnt contacts, burnt 

ribbons, broken or bent contacts, improperly installed ribbons, or evidence of moisture or other 
234-45 

foreign matter inside its housing is not considered properly maintained and is prohibited. 

Tests of operating characteristics include pickup, release, and working values. They may be 

recorded in either voltage or current values. 

CLASSIFICATION OF DEFECTS

234.263.A1 Tests of relay in service not made at least once every 4 years. 

234.263.B1 Tests of AC vane type relay, DC polar type relay, or relay with soft iron magnetic 

structure in service, not made at least once every 2 years. 

234.263.B2 Tests of AC centrifugal type relay in service not made at least once every 12 

months. 

§ 234.265 Timing relays and timing devices. 

 Each timing relay and timing device shall be tested at least once every twelve months. The 

timing shall be maintained at not less than 90 percent nor more than 110 percent of the 

predetermined time interval. The predetermined time interval shall be shown on the plans or 

marked on the timing relay or timing device. Timing devices which perform internal functions 

associated with motion detectors, motion sensors, and grade crossing predictors are not subject to 

the requirements of this section. 

Application: 

This section requires that each timing relay and timing device be tested at least once every 12 

months. The timing shall be maintained at not less than 90 percent nor more than 110 percent of 

the predetermined time interval. The predetermined time interval shall be shown on the plans or 

marked on the timing relay or timing device. 

Timing relays and timing devices are essential components of time-out circuits which are 

primarily used for train switching movements at active warning system installations using 

conventional relay type train detection circuits. 

Timing devices which perform internal functions associated with motion detectors, motion 

sensors, and grade crossing predictors are not subject to the requirements of this section. 

CLASSIFICATION OF DEFECTS

234.265.A1 Timing relay or timing device not tested at least once every 12 months. 

234.265.A2 Timing of timing relay or timing device less than 90 percent of predetermined 

time interval. 

234.265.A3 Timing of timing relay or timing device more than 110 percent of predetermined 

time interval. 
234-46 

234.265.A4 Predetermined time interval not shown on plans or marked on timing relay or 

timing device. 

§ 234.267 Insulation resistance tests. 

 (a) Insulation resistance tests shall be made when wires or cables are installed and at least 

once every ten years thereafter. 

 (b) Insulation resistance tests shall be made between all conductors and ground, between 

conductors in each multiple conductor cable, and between conductors in trunking. Insulation 

resistance tests shall be performed when wires, cables, and insulation are dry. 

 (c) Subject to paragraph (d) of this section, when insulation resistance of wire or cable is 

found to be less than 500,000 ohms, prompt action shall be taken to repair or replace the 

defective wire or cable. Until such defective wire or cable is replaced, insulation resistance tests 

shall be made annually. 

 (d) A circuit with a conductor having an insulation resistance of less than 200,000 ohms 

shall not be used. 

 (e) Required insulation resistance testing that does not conform to the required testing 

schedule of this section shall be completed in accordance with the following schedule: 

 (1) Not less than 50% by the end of calendar year 1996; 

 (2) Not less than a total of 75% by the end of calendar year 1997; and 

 (3) One hundred percent by the end of calendar year 1998. 

Application: 

This section requires that insulation resistance tests be made when wires or cables are installed 

and at least once every 10 years thereafter. 

Insulation resistance tests shall be made between all conductors and the ground and between all 

other wires or conductors within a cable. 

Track wires, line wires, and case wiring are excluded from the requirements of this rule. 

Where a conductor is found with insulation resistance of less than 500,000 ohms, prompt action 

is required for repair or replacement of the defective wire or cable. Until repair or replacement, 

insulation resistance tests must be made annually. The reason for this provision is to allow lead 

time for the acquisition of cable or scheduling of workforces. However, if material and work 

forces are available to effect repairs or replacement, corrective action shall be taken immediately. 

Where a conductor is found with insulation resistance of less than 200,000 ohms, the conductor 

shall be either repaired immediately or removed from service. 

CLASSIFICATION OF DEFECTS

234.267.A1 Tests of insulation resistance not made when installed, or at least once every 10 

years thereafter. 

234.267.B1 Tests of insulation resistance not made between all conductors and the ground, 

and between all conductors one to another. 
234-47 

234.267.C1 Action not taken to promptly repair or renew conductor having insulation 

resistance value less than 500,000 ohms. 

234.267.C2 Tests of insulation resistance not made at least annually of a conductor having 

insulation resistance value less than 500,000 ohms. 

234.267.D1 Circuit permitted to function on a conductor having insulation resistance value 

less than 200,000 ohms. 

§ 234.269 Cut-out circuits. 

 Each cut-out circuit shall be tested at least once every three months to determine that the 

circuit functions as intended. For purposes of this section, a cut-out circuit is any circuit which 

overrides the operation of automatic warning systems. This includes both switch cut-out circuits 

and devices which enable personnel to manually override the operation of automatic warning 

systems.

Application: 

This section requires that each cut-out circuit be tested at least once every 3 months to determine 

that the circuit functions as intended. 

For purposes of this section, a cut-out circuit is any circuit which overrides the operation of 

automatic warning systems. This includes reverse switch cut-out circuits and devices that enable 

personnel to manually override the operation of automatic warning systems. 

This section is not applicable to key switches that manually activate the warning system. 

CLASSIFICATION OF DEFECTS

234.269.A1 Cut-out circuit not tested at least once every 3 months. 

§ 234.271 Insulated rail joints, bond wires, and track connections.

 Insulated rail joints, bond wires, and track connections shall be inspected at least once every 

three months.

Application: 

This section requires that each insulated rail joint, bond wire, and track connection be inspected 

at least once every 3 months. 

Each insulated rail joint shall be inspected at least once every 3 months for compliance with 

§ 234.235. 

Each bond wire shall be inspected at least once every 3 months for compliance with § 234.233. 

Each track connection shall be inspected at least once every 3 months to maintain the integrity of 

the warning system. 
234-48 

CLASSIFICATION OF DEFECTS

234.271.A1 Insulated rail joint, bond wire, or track connection not inspected at least once 

every 3 months. 

§ 234.273 Results of inspections and tests. 

 (a) Results of inspections and tests made in compliance with this part shall be recorded on 

forms provided by the railroad, or by electronic means, subject to approval by the Associate 

Administrator for Safety. Each record shall show the name of the railroad, AAR/DOT inventory 

number, place and date, equipment tested, results of tests, repairs, replacements, adjustments 

made, and condition in which the apparatus was left. 

 (b) Each record shall be signed or electronically coded by the employee making the test and 

shall be filed in the office of a supervisory official having jurisdiction. Records required to be 

kept shall be made available to FRA as provided by 49 U.S.C. 20107 (formerly § 208 of the 

Federal Railroad Safety Act of 1970 (45 U.S.C. 437)). 

 (c) Each record shall be retained until the next record for that test is filed but in no case for 

less than one year from the date of the test.

Application: 

This section requires that the results of inspections and tests be recorded on forms provided by 

the railroad, or by electronic means, subject to approval by the Associate Administrator for 

Railroad Safety. Each record shall show the name of the railroad, AAR/DOT inventory number, 

place and date, equipment tested, results of tests, repairs, replacements, adjustments made, and 

condition in which the apparatus was left. 

Each record shall be signed or electronically coded by the employee making the test and shall be 

filed in the office of a supervisory official having jurisdiction. 

Each record shall be retained until the next record for that test is filed, but no less than one year 

from the date of the test. 

Each inspection or test performed in compliance with the requirements as set forth in sections 

234.249 through 234.271, inclusive, shall be recorded. 

FRA requires that railroads adopting electronic means of recording results of inspections and 

tests first obtain FRA approval through an application process. Requiring FRA approval will 

establish a process whereby FRA can ensure all the proper information (prescribed in paragraph 

(a)) is recorded. FRA will also be able to determine where and how the electronic records will 

be available for inspection. 

Any railroad wanting to implement electronic recordkeeping is required to obtain approval from 

FRA’s Associate Administrator for Railroad Safety. This process consists of a railroad 

submitting the following information to FRA’s Signal and Train Control Division Staff Director: 

1. A written action plan with a schedule for the implementation of the system. 
234-49 

2. A copy of each of the recordkeeping forms indicating how the results of all the applicable 

inspections or tests will be electronically recorded. 

3. A copy of the instructional or procedural manual for the use of the system. 

4. A written description of how FRA is expected and able to inspect the records. 

5. A written description of the training program concerning employee’s use of the 

recordkeeping system. 

 

FRA will then review the materials and subsequently notify the railroad of the result of our 

approval process. 

Electronic or automated tracking systems used to meet the requirements contained in paragraph 

(a) of this section must be capable of being reviewed and monitored by FRA at any time to 

ensure the integrity of the system. FRA’s Associate Administrator for Railroad Safety may 

prohibit or revoke a railroad’s authority to use an electronic or automated tracking system in lieu 

of preprinted forms if FRA finds that the electronic or automated tracking system is not properly 

secured; is inaccessible to FRA or FRA-certified State inspectors, or to railroad employees 

requiring access to discharge their assigned duties; or fails to adequately track and monitor the 

equipment. The Associate Administrator for Railroad Safety will provide the affected railroad 

with a written statement of the basis for his or her decision prohibiting or revoking the railroad 

from using an electronic or automated tracking system. (See Technical Bulletin S-99-06)

CLASSIFICATION OF DEFECTS

234.273.A1 Record of the results of inspections and tests not made. 

234.273.A2 Results of the results of inspections and tests not recorded on prescribed form or 

by electronic means. 

234.273.A3 Record of the results of inspection and test does not show name of railroad, DOT 

inventory number, place and date, equipment tested, results of tests, repairs, 

replacements, adjustments made, and condition in which apparatus was left. 

234.273.B1 Record of the results of inspection and test not signed or electronically coded by 

employee making the test. 

234.273.B2 Record of the results of inspection and test not filed in the office of a supervisory 

official having jurisdiction. 

234.273.B3 Record of the results of inspections and tests not readily available for FRA 

inspection. 

234.273.C1 Record of the results of inspections and tests not retained as required. 

Requirements for Processor-Based Systems 

 

§ 234.275 Processor-Based Systems. 

(a) Applicable definitions. The definitions in § 236.903 of this chapter shall apply to this 

section, where applicable. 
234-50 

(b) Use of performance standard authorized or required. (1) In lieu of compliance with the 

requirements of this subpart, a railroad may elect to qualify an existing processor-based product 

under part 236, subparts H or I of this chapter. 

 (2) Highway-rail grade crossing warning systems, subsystems, or components that are 

processor-based and that are first placed in service after June 6, 2005, which contain new or 

novel technology, or which provide safety-critical data to a railroad signal or train control system 

that is governed by part 236, subpart H or I of this chapter, shall also comply with those 

requirements. New or novel technology refers to a technology not previously recognized for use 

as of March 7, 2005. 

 (3) Products designed in accordance with subparts A through D of this part, which are not in 

service but are in the developmental stage prior to December 5, 2005 (or for which a request for 

exclusion was submitted prior to June 6, 2005, pursuant to § 236.911 of this chapter), may be 

excluded from the requirements of part 236, subpart H of this chapter upon notification to FRA 

by March 6, 2006, if placed in service by December 5, 2008 (or March 7, 2008 for those 

products for which a request for exclusion was submitted to FRA prior to June 6, 2005). 

Railroads may continue to implement and use these products and components from these 

existing products. A railroad may at any time elect to have products that are excluded made 

subject to 49 CFR part 236, subpart H, by submitting a Product Safety Plan as prescribed in 

§ 236.913 of this chapter and otherwise complying with part 236, subpart H of this chapter. 

 (c) Product safety plan justifications. The Product Safety Plan in accordance with 49 CFR 

236.907 – or a PTC Development Plan and PTC Safety Plan required to be filed in accordance 

with 49 CFR 236.1013 and 236.1015 – must explain how the performance objective sought to be 

addressed by each of the particular requirements of this subpart is met by the product, why the 

objective is not relevant to the product’s design, or how safety requirements are satisfied using 

alternative means. Deviation from those particular requirements is authorized if an adequate 

explanation is provided, making reference to relevant elements of the applicable plan, and if the 

product satisfies the performance standard ser forth in § 236.909 of this chapter. (See § 

236.907(a)(14) of this chapter.) 

 (d) Specific requirements. The following exclusions from the latitude provided by this 

section apply: 

 (1) Nothing in this section authorizes deviation from applicable design requirements for 

automated warning devices at highway-rail grade crossings in the Manual on Uniform Traffic 

Control Devices (MUTCD), 2000 Millennium Edition, Federal Highway Administration 

(FHWA), dated December 18, 2000, including Errata #1 to MUTCD 2000 Millennium Edition 

dated June 14, 2001 (http://mutcd.fhwa.dot.gov/). 

 (2) Nothing in this section authorizes deviation from the following requirements of this 

subpart: 

(i) § 234.207(b) (Adjustment, repair, or replacement of a component); 

 (ii) § 234.209(b) (Interference with normal functioning of system); 

 (iii) § 234.211 (Security of warning system apparatus); 

 (iv) § 234.217 (Flashing light units); 

 (v) § 234.219 (Gate arm lights and light cable); 

 (vi) § 234.221 (Lamp voltage); 

 (vii) § 234.223 (Gate arm); 

 (viii) § 234.225 (Activation of warning system); 

 (ix) § 234.227 (Train detection apparatus)–if a train detection circuit is employed to 

determine the train’s presence; 

 (x) § 234.229 (Shunting sensitivity)–if a conventional track circuit is employed; 

 (xi) § 234.231 (Fouling wires)–if a conventional train detection circuit is employed; 
234-51 

 (xii) § 234.233 (Rail joints)–if a track circuit is employed; 

 (xiii) § 234.235 (Insulated rail joints)–if a track circuit is employed; 

 (xiv) § 234.237 (Reverse switch cut-out circuit); or 

 (xv) § 234.245 (Signs). 

 (e) Separate justification for other than fail-safe design. Deviation from the requirement of § 

234.203 (Control Circuits) that circuits be designed on a fail-safe principle must be separately 

justified at the component, subsystem, and system level using the criteria of 

§ 236.909 of this chapter. 

 (f) Software management control for certain systems not subject to a performance standard. 

Any processor-based system, subsystem, or component subject to this part, which is not subject 

to the requirements of part 236, subpart H or I of this chapter but which provides safety-critical 

data to a signal or train control system shall be included in the software management control plan 

requirements as specified in § 236.18 of this chapter. 

 

Application: 

This section contains standards applicable to highway-rail grade crossing active warning systems 

that use new or novel technology. This section is equally applicable to all highway-rail grade 

crossing warning systems that provide safety-critical data to a product subject to the provisions 

of Part 236, Subpart H or I. The provisions contained in this section are relevant only to Part 

234, Subpart D. 

Definitions contained in §§ 236.903 and 236.1003 are applicable, as appropriate, to equipment 

and systems subject to this section. 

New or novel technology refers to a technology not previously recognized for use in highwayrail grade crossing warning systems prior to March 7, 2005. Some examples of new or novel 

technology captured by the provisions of this section are systems envisioned by the Intelligent 

Transportation System (ITS) where data is transmitted to and integrated with highway traffic 

control/information systems, systems that do not use conventional track circuits for train 

detection, and systems that may use data transmitted from approaching trains to warn motor 

vehicle operators of their approach to or occupancy of a crossing. 

Processor-based equipment and systems in service on or before June 6, 2005, and not 

interconnected with a signal and train control system, may continue to be installed and utilized 

subject to all other requirements of Part 234. 

There are two ways existing systems excluded by design and implementation may become 

subject to the provisions of this section: (1) a railroad may elect to qualify an existing product 

under Subpart H; or (2) installation of a signal and train control system subject to the provisions 

of Part 236, Subpart H or I, in which existing highway-rail grade crossing warning systems are 

modified to provide safety-critical data to that newly installed system (e.g., pre-start warnings for 

higher train speeds). 

Highway-rail grade crossing warning systems subject to this section must be developed in 

accordance with either a Product Safety Plan (PSP) meeting the definition identified in § 

236.903, or a Positive Train Control (PTC) Development Plan (PTCDP) or PTC Safety Plan 

(PTCSP) meeting the definition identified in § 236.1003. Additionally, the PSP, or PTCDP or 

PTCSP must explain how the performance objective sought to be addressed by each of the 
234-52 

particular requirements of Part 234 is met by the product, why the objective is not relevant, or 

how safety requirements are satisfied by alternative means. This section provides for deviation 

from those particular requirements of Part 234 if an adequate explanation is provided, making 

reference to relevant elements of the applicable plan, and if the product satisfies the performance 

standard prescribed in § 236.909. 

Processor-based equipment used in highway-rail grade crossing warning systems which provide 

safety-critical data to a railroad signal or train control system are required to be included in the 

software management control plan prescribed in § 236.18. 

Nothing in this section authorizes deviation from applicable design requirements for automated 

warning devices at highway-rail grade crossings in the MUTCD, 2000 Millennium Edition, 

FHWA, dated December 18, 2000, including Errata #1 to MUTCD 2000 Millennium Edition, 

dated June 14, 2001. 

Further, nothing in this section authorizes deviation from the following requirements of Subpart 

D: 

§ 234.207(b) Adjustment, repair, or replacement of a component. 

§ 234.209(b) Interference with normal functioning of a system. 

§ 234.211 Security of warning system apparatus. 

§ 234.217 Flashing light units. 

§ 234.219 Gate arm lights and light cable. 

§ 234.221 Lamp voltage. 

§ 234.223 Gate arm. 

§ 234.225 Activation of the warning system. 

§ 234.227 Train detection apparatus–if a train detection circuit is employed to determine 

the train’s presence. 

§ 234.229 Shunting sensitivity–if a conventional track circuit is employed. 

§ 234.231 Fouling wires–if a conventional train detection circuit is employed. 

§ 234.233 Rail joints–if a track circuit is employed. 

§ 234.235 Insulated rail joints–if a track circuit is employed. 

§ 234.237 Reverse switch cut-out circuit. 

§ 234.245 Signs. 

This section does authorize deviation from the requirements of § 234.203 (Control circuits) 

requiring that circuits be designed on a fail-safe principle provided the deviation is separately 

justified at the component, subsystem, and system level using the criteria set forth in 

§ 236.909. 

Any processor-based system, subsystem, or component subject to this part, which is not subject 

to the requirements of Part 236, Subpart H or I of this chapter, but which provides safety-critical 

data to a signal or train control system, shall be included in the software management control 

plan requirements as specified in § 236.18 of this chapter. (See Technical Bulletins S-06-01 and 

S-07-01)
234-53 

CLASSIFICATION OF DEFECTS

234.275. A1 Definition contained in §§ 236.903 or 236.1003, where applicable, not applied to 

processor-based highway-rail grade crossing active warning system using new or 

novel technology. 

234.275.A2 Definition contained in §§ 236.903 or 236.1003, where applicable, not applied to 

processor-based highway-rail grade crossing active warning system providing 

safety-critical data to a product governed by Part 236, Subpart H or I. 

234.275.A3 Definition used for product subject to this section does not comply with the 

definition contained in §§ 236.903 or 236.1003. 

234.275.B1 Highway-rail grade crossing active warning system using new or novel 

technology does not comply with requirements contained in Part 236, Subpart H 

or I. 

234.275.B2 Highway-rail grade crossing active warning system which provides safety-critical 

data to a railroad signal or train control system does not comply with 

requirements contained in § 236.18. 

234.275.C1 Highway-rail grade crossing active warning system using new or novel 

technology implemented without an FRA-approved PSP, or PTCDP or PTCSP as 

applicable. 

234.275.D1 Highway-rail grade crossing warning system does not comply with applicable 

design requirements of the Manual on Uniform Traffic Control Devices. 

234.275.E1 Deviation from the requirements of § 234.203 not separately justified at the 

component, subsystem, and/or system level. 

234.275.E2 Justification for deviation from the requirements of § 234.203 does not conform 

to the criteria of § 236.909. 

234.275.F1 Software management control plan not implemented for highway-rail grade 

crossing warning system which provides safety-critical data to a railroad signal or 

train control system as required by § 236.18.
234-54 

Alternate Means of Warning 

Under 49 CFR §§ 234.105(c), 234.106, and 234.107(c)

This is a summary—See body of text for complete requirements 

Flagger For Each 

Direction of 

Traffic

Police 

Officer 

Present

Flagger 

Present, But 

Not One For 

Each 

No Flagger/ 

No Police

False 

Activation Normal Speed Normal 

Speed 

Proceed with 

caution– 

maximum speed 

of 15 mph 

Proceed with 

caution– 

maximum speed 

of 15 mph 

Partial 

Activation* Normal Speed Normal 

Speed 

Proceed with 

caution– 

maximum speed 

of 15 mph 

Proceed with 

caution– 

maximum speed 

of 15 mph 

Activation 

Failure** Normal Speed Normal 

Speed 

Proceed with 

caution– 

maximum speed 

of 15 mph 

Stop: Crew 

member flag 

traffic and reboard 

* Partial activation–full warning not given. 

Non-gated crossing with one pair of lights designed to flash alternatively, one light does not 

work (and back lights from other side not visible). 

Gated crossing–gate arm not horizontal; or any portion of a gate arm is missing if that portion 

had held a gate arm flashing light. 

**Activation failure includes–if more than 50 percent of the flashing lights on any approach lane 

not functioning; or if an approach lane has two or more pairs of flashing lights, there is not at 

least one pair operating as intended. 

 
234-55 

Activation Failure; Not one operating pair.

Partial Activation; Full warning not given for each lane of approaching traffic.

Track speed, facing pair of back lights visible to highway user.
234-56 

Partial Activation, single pair of flashing lights on approach to crossing, no back lights visible. 

Partial Activation, gate arm broken holding flashing marker light. 

Track Speed; Gate arm tip broken outside of flashing gate lights.
235-1 

49 CFR Part 235 – Instructions Governing Applications for Approval of a

Discontinuance or Material Modification of a Signal System or Relief

from the Requirements of Part 236

 § 235.1 Scope. 

 § 235.3 Application. 

 § 235.5 Changes requiring filing of application. 

 § 235.7 Changes not requiring filing of application. 

 § 235.8 Relief from the requirements of part 236 of this title. 

 § 235.9 Civil penalty. 

 § 235.10 Contents of applications. 

 § 235.12 Additional required information-prints. 

 § 235.13 Filing procedure. 

 § 235.14 Notice. 

 § 235.20 Protests. 

Investigation of Applications and Field Report Format 

 
235-2 

§ 235.1 Scope.

 This part prescribes application for approval to discontinue or materially modify block signal 

systems, interlockings, traffic control systems, automatic train stop, train control, or cab signal 

systems, or other similar appliances, devices, methods, or systems, and provides for relief from 

part 236 of this title.

Application: 

This section identifies those changes in signal and train control systems, methods, and appliances 

that require FRA approval, those that are exempt from approval, and provides for relief from the 

RS&I. 

This section is applicable to all: 

 Block signal systems 

 Interlockings 

 Traffic control systems 

 Automatic train stop, automatic train control, or automatic cab signal systems 

 Other similar appliances, methods, or systems 

§ 235.3 Application.

 (a) Except as provided in paragraph (b) of this section, this part applies to railroads that 

operate on standard gage track which is part of the general railroad system of transportation. 

 (b) This part does not apply to rail rapid transit operations conducted over track that is used 

exclusively for that purpose and that is not part of the general system of railroad transportation. 

Application: 

This section makes this part applicable to each common carrier by rail subject to the Signal 

Inspection Act, 49 U.S.C. 205. 

This part applies to each railroad that is part of the general railroad system of transportation. 

This part does not apply to rapid transit systems or privately owned systems not transporting 

interstate commerce. 

§ 235.5 Changes requiring filing of application.

 (a) Except as provided in § 235.7, applications shall be filed to cover the following: 

 (1) The discontinuance of a block signal system, interlocking, traffic control system, 

automatic train stop, train control, or cab signal system or other similar appliance or device; 

(2) The decrease of the limits of a block signal system, interlocking, traffic control system, 

automatic train stop, train control, or cab signal system; or 

 (3) The modification of a block signal system, interlocking, traffic control system, automatic 

train stop, train control, or cab signal system. 

 (b) [Reserved] 
235-3 

Application: 

This section prescribes application (1) for approval of discontinuance, (2) to decrease of limits of 

a system, or (3) for material modification, except as exempted in § 235.7. 

Failure of a railroad to adhere to the conditions of an approval shall be cited as a discontinuance 

of, decrease in the limits of, or material modification of a system without approval under this 

section. 

Except as provided in § 235.7, an application must be filed to cover the discontinuance of a 

block signal system, interlocking, traffic control system, automatic train stop, automatic train 

control, or automatic cab signal system, or other similar appliances or devices. Except as 

provided in § 235.7, an application must also be filed to cover the decrease of the limits or 

modification of a block signal system, interlocking, traffic control system, automatic train stop, 

train control, or cab signal system. 

Other similar appliances or devices are considered to be signal arrangements or protective 

devices (such as slide detectors, high-water detectors, or earthquake detectors) that are 

interconnected with a signal system. 

A signal arrangement comprises signaling installations (such as tunnel protection, spring switch 

protection, etc.) that govern train movements but do not meet the requirements of Subpart B, C, 

or D. 

This section does not apply to automatic classification yards or highway-rail grade crossing 

warning devices. 

Except as provided in § 235.7, a material modification includes, but is not limited to, the 

following: 

1. Change in type of interlocking from manual to automatic. 

2. Change in type of signal system from traffic control to automatic block; interlocking to 

traffic control; or traffic control to interlocking. 

4. Signal respacing projects involving the removal of signals to reduce maintenance costs. 

5. Conversion of power-operated switches/derails to hand or spring operation. 

CLASSIFICATION OF DEFECTS

235.5.A1 Discontinuance without FRA approval. 

235.5.A2 Decrease of the limits without FRA approval. 

235.5.A3 Material modification without FRA approval. 

§ 235.7 Changes not requiring filing of application.

 (a) It is not necessary to file an application for approval of the following discontinuances: 

 (1) Removal of block signal system, interlocking, traffic control system, automatic train 

stop, train control, or cab signal system from track approved for abandonment by formal 
235-4 

proceeding; 

 (2) Removal of devices and associated signals used to provide protection against unusual 

contingencies such as landslide, burned bridge, high water, high and wide load, or tunnel 

protection when the unusual contingency no longer exists; 

 (3) Removal of an interlocking where a drawbridge has been permanently closed by the 

formal approval of another government agency; or 

 (4) Removal from service not to exceed 6 months of block signal system, interlocking, or 

traffic control system necessitated by catastrophic occurrence such as derailment, flood, fire, or 

hurricane; or, 

 (5) Removal of an intermittent automatic train stop system in conjunction with the 

implementation of a positive train control system approved by FRA under subpart I of part 236 

of this chapter. 

 (b) When the resultant arrangement will comply with part 236 of this title, it is not necessary 

to file for approval to decrease the limits of a system as follows: 

 (1) Decrease of the limits of an interlocking when interlocked switches, derails, or 

movable-point frogs are not involved; 

 (2) Removal of electric or mechanical lock, or signal used in lieu thereof, from handoperated switch in automatic block signal or traffic control territory where train speed over 

switch does not excess 20 miles per hour; or 

 (3) Removal of electric or mechanical lock, or signal used in lieu thereof, from handoperated switch in automatic block signal or traffic control territory where trains are not 

permitted to clear the main track at such switch. 

 (c) When the resultant arrangement will comply with part 236 of this title, it is not necessary 

to file an application for approval of the following modifications: 

 (1) A modification that is required to comply with an order of the Federal Railroad 

Administration or any section of part 236 of this title; 

 (2) The installation of an automatic block signal or a traffic control system to replace manual 

block or non-signaled territory; 

 (3) The installation of a traffic control system to replace a roadway automatic block signal 

system (discontinuance of an automatic train stop, train control, or cab signal system is not 

permitted without FRA approval); 

 (4) The installation of an automatic train stop, train control, or cab signal system in an 

existing automatic block or traffic control system; 

 (5) The installation of a continuous inductive automatic train stop system to replace an 

existing intermittent inductive automatic train stop system; 

 (6) The installation of a continuous inductive automatic train stop system to supplement an 

existing automatic cab signal system; 

 (7) The installation of an automatic train control system to replace an existing automatic 

train stop system or to supplement an existing automatic cab signal system; 

 (8) The installation of an interlocking to replace existing stop signs, gates, or pipe-connected 

derails protecting a railroad crossing at grade; 

 (9) The installation of all relay type locking to replace existing mechanical or electro 

mechanical locking of an interlocking; 

 (10) The installation of an additional controlled point in existing traffic control system; 

 (11) The installation of an interlocking in an existing block signal system; 

 (12) The conversion of a hand-operated switch, a hand-operated switch locked either 

electrically or mechanically, or a spring switch to a power-operated switch; 

 (13) The conversion of a spring switch to a hand-operated switch, or to a hand-operated 

switch locked either electrically or mechanically; 
235-5 

 (14) The removal or relocation of signals associated with a spring switch converted to hand 

operation; 

 (15) The installation, relocation, or removal of signals to specifically provide adequate 

stopping distance; 

 (16) The change of aspects; 

 (17) The relocation of a signal to improve preview of signal aspect visibility; 

 (18) To replace a signal with a signal of another type; 

 (19) To change an approach signal to operative or inoperative signal, or remove an approach 

signal not required by § 236.310 of this title; 

 (20) The change in location of a machine from which an interlocking or traffic control 

system is controlled; 

 (21) The closing of a manual block station or the change in hours during which a manual 

block station is attended; 

 (22) The change in hours during which a manual interlocking is attended provided the 

interlocking operates for all routes over which train movements are permitted; 

 (23) The installation of devices used to provide protection against unusual contingencies 

such as landslide, burned bridges, high water, high and wide loads, or dragging equipment; 

 (24) The installation, relocation, or removal of signals, interlocked switches, derails, 

movable-point frogs, or electric locks in an existing system directly associated with: 

 (i) The installation of new track; 

 (ii) The elimination of existing track other than a second main track; 

 (iii) The extension or shortening of a passing siding; 

 (iv) Elimination of second main track where signal system on retained main track is 

arranged to provide both opposing and following protection for train movements provided 

second main track is physically removed; or 

 (v) A line relocation; or 

 (vi) The conversion of pole line circuits to electronic (coded) track circuits provided that the 

railroad gives notice and a profile plan of the change to the FRA regional office having 

jurisdiction over that territory at least 60 days in advance of the change. The railroad must also 

at the same time provide a copy of the notice and profile plan to representatives of employees 

responsible for maintenance, inspection and testing of the signal system under 49 CFR Part 236. 

The signal system modification will be deemed acceptable, unless within 60 days, the Regional 

Administrator stays action by written notice to the railroad and refers the issue to the Railroad 

Safety Board for decision. 

 (25) The temporary or permanent arrangement of existing systems necessitated by highwayrail grade crossing separation construction. Temporary arrangements shall be removed within 6 

months following completion of construction. 

Application: 

This section specifically identifies those changes permitted without FRA approval. 

Signal changes not shown in this section are considered to be discontinuances, decrease of the 

limits, or material modifications that require FRA approval. 

§ 235.8 Relief from the requirements of part 236 of this title.

 Relief from the requirements of the rules, standards, and instructions contained in part 236 of 

this title will be granted upon an adequate showing by an individual carrier. Relief heretofore 
235-6 

granted to any carrier shall constitute relief to the same extent as relief granted under the 

requirements of this part. 

Application: 

This section is to indicate that relief from any requirement contained in the RS&I will be granted 

if adequate justification is provided in the request submission to the FRA. It is intended to 

indicate that the FRA Railroad Safety Board will make such a decision, in the same manner as it 

does related to requests for signal or train control system discontinuance, decrease in limits, or a 

material modification, based upon a sufficient and acceptable safety case being included with 

each such request which supports that the relief being granted would be in the interest of public 

safety. 

The provisions of this section were formerly contained in § 236.0. Relief from the requirements 

of the RS&I previously granted to any carrier constitutes relief to the same extent as relief 

granted under the requirements of this part. 

§ 235.9 Civil penalty. 

 Any person (an entity of any type covered under 1 U.S.C. 1, including but not limited to the 

following: a railroad; a manager, supervisor, official, or other employee or agent of a railroad; 

any owner, manufacturer, lessor, or lessee of railroad equipment, track, or facilities; any 

independent contractor providing goods or services to a railroad; and any employee of such 

owner, manufacturer, lessor, lessee, or independent contractor) who violates any requirement of 

this part or causes the violation of any such requirement is subject to a civil penalty of at least 

$650 and not more than $25,000 per violation, except that: Penalties may be assessed against 

individuals only for willful violations, and, where a grossly negligent violation or a pattern of 

repeated violations has created an imminent hazard of death or injury to persons, or has caused 

death or injury, a penalty not to exceed $100,000 per violation may be assessed. Each day a 

violation continues shall constitute a separate offense. See appendix A to this part for a 

statement of agency civil penalty policy. 

Application: 

This section establishes a civil penalty for failure to comply with the requirements of this part. 

Where, for any reason, a carrier does not file an application to cover a discontinuance, decrease 

in limits, or a material modification, this section prescribes a maximum civil penalty of $25,000 

per violation, except in extraordinary circumstances where the maximum penalty may be 

increased to $100,000 per violation. Each day a failure to file continues is a separate offense. 

§ 235.10 Contents of applications.

 (a) The application may be submitted by letter and shall contain the following 

information: 

 (1) The corporate name of each applicant; 

 (2) The manner in which applicant is involved; 

 (3) The location of the project, giving name of operating division and nearest station; 

 (4) The track or tracks involved; 

 (5) A complete description of proposed changes as they would affect the existing facilities 
235-7 

or of the section from which relief is sought; 

 (6) The reason for proposed changes or justification for relief from the requirements; 

 (7) The approximate dates of beginning and completion of project; 

 (8) Changes in operating practices, temporary or permanent; 

 (9) Whether safety of operation will be affected, and if so, how; and 

 (10)Whether proposed changes will conform to the Federal Railroad Administration’s 

Rules, Standards, and Instructions (part 236 of this title). 

 (b) [Reserved]

§ 235.12 Additional required information-prints. 

 (a) A print or prints, size 8 inches by 101⁄2 inches, or 81⁄2 inches by 11 inches, or folded to 8 

inches by 101⁄2 inches or to 81⁄2 inches by 11 inches, shall be furnished with each application. 

 (b) The print or prints shall be to scale or by indicated dimensions, using Association of 

American Railroads graphic symbols. 

 (c) The following information shall be shown on the print or prints: 

 (1) Present and proposed arrangement of tracks and signal facilities; 

 (2) Name of carrier; 

 (3) Operating division; 

 (4) Place and State; and 

 (5) Timetable directions of movements. 

 (d) If stopping distances are involved, the following information shall also be shown: 

 (1) Curvature and grade; 

 (2) Maximum authorized speeds of trains; and 

 (3) Length of signal control circuits for each signal indication displayed. 

 (e) The following color scheme is suggested on prints: 

 (1) Installations, relocations, and added signal aspects should be colored, preferably in 

yellow; 

 (2) Removals, discontinuances, and abandonments should be colored, preferably in red; 

and 

 (3) Existing facilities not pertinent to change proposed in application should be shown 

uncolored.

Application: 

These sections set forth the information that is required when submitting an application. 

These sections itemize the information that is required on block signal applications and 

applications for relief from the RS&I. 

§ 235.13 Filing procedure.

 (a) Applications or requests for reconsideration of an application shall be submitted by an 

authorized officer of the carrier. 

 (b) The original and two copies of each application with supporting papers should be filed. 

 (c) The application and correspondence in reference thereto should be addressed to the 

Associate Administrator for Safety, Federal Railroad Administration, Washington, DC 20590. 

 (d) A separate application shall be filed for each project. 
235-8 

 (e) At a joint facility where changes are proposed in the automatic block signal system, 

interlocking, traffic control system, automatic train stop, train control, or cab signal system on 

the tracks of more than one carrier, or if more than one carrier will be affected by the proposed 

changes or relief sought, a joint application signed by all carriers affected shall be filed. 

 (f) Where only one carrier at a joint facility is affected by the discontinuance or 

modification of the installation or relief sought, it shall be responsible for filing the application. 

It shall also certify that the other joint carriers have been notified of the filing of its application.

Application: 

This section sets forth the procedure for filing an application. 

This section prescribes the manner in which block signal applications and applications for relief 

are to be filed. 

At a joint facility, where the proposed changes affect more than one carrier, the application must 

be executed between the joint carriers before submitting to FRA. 

At a joint facility, where the proposed changes or relief sought affect only one carrier, that carrier 

shall certify when filing that the other joint carriers have been notified of the application. 

§ 235.14 Notice.

 The FRA will publish notice of the filing of an application or a request for reconsideration of 

an application in the FEDERAL REGISTER and a copy of such notice will be available at the U.S. 

Department of Transportation, Docket Operations (M-30), West Building Ground Floor, Room 

W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, and on the Federal Docket 

Management System’s Web site at http://www.regulations.gov.

Application: 

This section provides for the posting of a public notice in connection with the filing of each 

application or request for reconsideration. 

FRA will post a public notice of the filing of an application or request for reconsideration of an 

application in the FRA Office of Public Affairs. This public notice may be examined at FRA’s 

headquarters in Washington, DC, during regular business hours. A copy of each public notice 

will be mailed to all interested parties. 

§ 235.20 Protests.

 (a) A protest against the granting of an application shall set forth specifically the grounds 

upon which it is made, and contain a concise statement of the interest of protestant in the 

proceeding. 

 (b) Protests shall be filed with the Associate Administrator for Safety, Federal Railroad 

Administration, Washington, DC 20590, and one copy shall be furnished to each applicant. 

 (c) Protests should be filed within the time limit set forth in the public notice. 

 (d) The protestant shall certify that service of a copy of its protest was made upon each 

applicant. 
235-9 

 (e) Request for hearing must be accompanied with a showing why the protestant is unable to 

properly present his or her position by written statements. 

 Effective Date Note: At 49 FR 3380, Jan. 26, 1984, part 235 was revised. This section 

contains information collection and recordkeeping requirements and will not become effective 

until approval has been given by the Office of Management and Budget. 

Application: 

This section explains how a protest can be made against granting any application. 

This rule prescribes the method and procedure for filing a protest against granting a block signal 

application or an application for relief from the requirements of the RS&I. Protests not filed in 

the prescribed time limit may not be considered. 

 
235-10 

Investigation of Applications

A thorough investigation and a complete report are required on each application for relief from 

the requirements of the RS&I (RS&I-Ap) and on each application for approval of a 

discontinuance, decrease in the limits, or material modification of a block signal system, 

interlocking, automatic train stop, train control, and cab signal device (BS-Ap). 

The information submitted by the carrier in accordance with the provisions contained in 49 CFR 

Part 235, Instructions Governing Applications for Approval of a Discontinuance or Material 

Modification of a Signal System or Relief from the Requirements of Part 236, will form the basis 

for the investigation report associated with each BS-Ap and RS&I-Ap. This information should 

be checked at the time of investigation to ensure that it is correct for use in the preparation of the 

report, and so that any additional information needed to complete the report may be obtained 

promptly. Two copies of this information will be provided with each application assigned for 

field investigation. One copy is to be retained in the inspector’s file. 

Each application should be promptly investigated. A field investigation report should be 

prepared and mailed in time to reach the headquarters staff in Washington, DC, prior to the 

closing date shown on the public notice. 

The field investigation report shall be prepared on the inspector’s “Report Form for BS-Ap and 

RS&I-Ap Applications” according to the instructions contained herein. 

On the first line, the FRA docket number should be inserted, the type “RS&I-Ap” or “BS-Ap” 

should be struck out as appropriate, and the filing date inserted. The filing date is the date the 

application was received in headquarters and is stamped on the application letter.

On the second line, insert the inspector’s name, headquarters location, and date the report is 

prepared. 

On the third line, insert the name of the railroad filing the application. For joint applications, 

each railroad that is a party to the application shall be shown. Do not show the name of the 

railroad official filing the application or the address of the carrier. 

On the fourth and fifth lines, show the required information. Be sure to indicate the carrier or 

organization with which the representatives are associated. 

In paragraph (a), the inspector certifies whether the public notice is correct by placing an “X” in 

the appropriate parenthesis. Where the public notice is found to be in error, the inspector should 

insert the correct language. It is also recommended that the inspector edit the correction into a 

copy of the public notice and return it with the report. 

In paragraph (b), the inspector should identify other railroads that operate in the facilities 

involved through joint ownership, trackage rights, tenant agreement, switching agreement, etc., 

that will be affected by the proposed changes but were not shown in the public notice. The 

inspector should describe the manner in which each railroad will be affected. In addition, the 

inspector should determine whether the carriers have been made party to the application or duly 

notified of the proposed changes or relief as required. 
235-11 

In paragraph (c), the inspector should identify any additional documents obtained during the 

field investigation and included as part of the field report. A timetable, or a copy of the 

scheduled page involved, along with applicable special instructions should be included with each 

application. 

Photographs of the application area and related devices should be included to assist the Safety 

Board in its deliberations. 

Paragraphs (d) 1, 2, 3, 4, and 5 shall be prepared on pages 1a, 1b, 1c, etc., as necessary. 

In (d) 1, the inspector should provide a thorough technical description of the existing signal 

installation and equipment (i.e., derails, defect detectors, and other pertinent devices). 

Descriptions of terrain, methods of operation, etc., should be avoided. Examples of technical 

descriptions required are: 

 “An automatic block signal system on two main tracks arranged for movements with the 

current of traffic having US&S P-5 colorlight type signals controlled by d.c. non-coded 

track and line circuits.” 

 “A traffic control system on a single main track having US&S H-2 searchlight type 

signals and US&S M-23 electric power-operated switch machines controlled by d.c. 

coded track circuits operated from a GRS CAD control machine located in Springfield, 

Missouri.” 

 “A manual interlocking having GRS Model 2A upper quadrant semaphore signals and 

GRS Model 5A electric power-operated switch machines controlled by d.c. non-coded 

track and line circuits operated from a 27-lever GRS Model 2 interlocking machine.” 

In (d) 2, the inspector should describe the proposed changes or relief requested. 

In (d) 3, the inspector should describe any proposed changes not described in the public notice. 

Do not use this paragraph for correction of mechanical errors corrected in paragraph (a). 

Use this paragraph to describe the proposed changes where the public notice does not clearly do 

so. 

In (d) 4, the inspector should provide an adjective description of the present and proposed 

methods of operation. The inspector should also describe the methods of operation on the 

trackage on either side of the limits covered by the application. 

The inspector should verify the present method of operation with the carrier’s timetable and 

operating rules. 

The proposed method of operation should include specific details and procedures at locations 

such as an unprotected crossing at grade or an unprotected movable bridge. 

Do not show operating rules as methods of operation. Examples of adjective descriptions are: 
235-12 

 “The present method of operation is by timetable and train orders supplemented by the 

indications of an automatic block signal system. The proposed method of operation is by 

signal indications of a traffic control system.” 

 “The present method of operation is by timetable, train orders, and signal indications of 

an automatic block signal system on two main tracks arranged for movements with the 

current of traffic. The proposed method of operation is by signal indication of a traffic 

control system.” 

 “The present method of operation is by signal indications of an automatic interlocking 

and will not be affected by the proposed changes.” 

In the second paragraph of (d) 4, the inspector should describe the daily number of trains or 

other movements in the area involved. Train averages should be based on a 30-day period that is 

representative of normal traffic. Avoid periods having seasonal traffic, such as grain harvests, 

planting seasons, or a period of train detours. Train movements should be expressed 

distinguishing passenger trains from freight trains; through freight trains from local switchers. 

Train movements may be expressed in columned format or adjectivally. Where the average 

number of trains is less than one daily, show the average number per week. 

Train movements should be broken down separately for each carrier operating over the 

application area. 

The areas of operation for local train movements should be specifically defined if they do not 

operate over the entire application area. 

Where there are numerous switching movements in terminal or yard areas, the number of daily 

switch engine assignments may be shown. 

The inspector should make his or her best effort to determine the potential for traffic or 

interchange growth on the line. 

The inspector should note whether the involved trackage is subject to detours, and should state 

the last 2-year detour history. 

In addition, it should be noted whether the involved trackage is part of the Strategic Rail 

Network (STRACNET). 

In the last paragraph of (d) 4, the inspector should address speed restrictions and authorizations. 

The present and proposed maximum authorized speeds should be shown. Where various speeds 

are prescribed for different trains, the trains should be identified, e.g., passenger trains, traileron-flatcar or van trains, hazardous materials trains, and other freight trains but not including 

work trains, cranes, scale cars, etc. Speed restrictions that have a bearing on the proposed 

changes should be identified. 

The inspector should reconcile that the proposed maximum authorized speed corresponds with 

the proposed method of operation. 
235-13 

In (d) 5, the inspector should state in the first paragraph whether the National Railroad Passenger 

Corporation (Amtrak) operated trains over the trackage involved in the application on February 

1, 1979. 

The second paragraph of (d) 5 should show the number of hazardous materials cars transported 

annually over the trackage involved in the application. Any discrepancies in carrier’s hazardous 

material information must be reconciled. 

When applicable, the third paragraph of (d) 5 should show the BS-Ap or RS&I-Ap number 

filed concurrently with the application. In subsequent paragraphs of (d) 5, the inspector should 

provide additional information deemed necessary to fully understand the proposal, such as 

changed traffic patterns and their causes, design problems, maintenance practices, obsolescence, 

vandalism, terrain, adverse weather conditions, etc. 

On page 2, the inspector should complete items (e) and (f) on BS-Ap’s only. 

In (e) 1, describe the work, if any, found accomplished in connection with the proposed changes. 

In (e) 2, the inspector should provide complete details on proposed changes found placed in 

service without approval. Use additional pages if more space is needed, numbering them 2a, 2b, 

2c, etc. 

In (f), the inspector should show whether the proposed changes of a BS-Ap will comply with the 

requirements contained in RS&I-Ap. If not, identify the rule number and provide details on the 

deficiency. 

In (g), the inspector should check the appropriate description which most aptly states the 

consequences, in the inspector’s opinion, if the proposed changes or relief are approved. 

The inspector’s opinion and reasoning should not be based on personal preferences, but should 

be fair and impartial within the guidelines and provisions contained in the RS&I-Ap, and with 

due regard for the safety of train operations. 

In (h), the inspector must provide a recommendation as to the disposition of the application. 

Keep in mind that this is where the initial agency policy begins concerning the proposed 

changes. The inspector may recommend that the application be approved, approved in part and 

denied in part, denied, or approved with provisions. The inspector must state the reasons upon 

which his or her recommendations are based. Where provisions are recommended, the inspector 

should clearly support the need for each provision. Use additional pages if more space is 

necessary, numbering 2a, 2b, 2c, etc. 

The investigative report should be based on factual remarks and documented information, and 

should support the inspector’s ultimate conclusion and recommendation. Ambiguous statements 

should be avoided. 

Inspectors are encouraged to insert appropriate information on the plans furnished with the 

applications. Notations on the plans are to be made in lead pencil and initialed. In no case shall 

a plan be marked in color. 

In (i), the appropriate S&TC regional supervisory specialist should review the inspector’s report, 

and subsequently make a recommendation as to the disposition of the application. If the 
235-14 

supervisory specialist’s recommendation differs from that of the inspector, the supervisory 

specialist should state the reasons and provide additional information, if necessary. 

 

Every March and September, inspectors shall submit a Progress and Completion Report, Form 

FRA F6180.50 for each BS-Ap until completed. Progress and completion reports are not 

required for RS&I-Aps. When progress and completion reports indicate that a railroad has not 

started or completed approved changes, FRA may request that the railroad withdraw the BS-Ap. 
235-15 

DEPARTMENT OF TRANSPORTATION 

FEDERAL RAILROAD ADMINISTRATION 

Report in re: RS&I-Ap. 

Docket No. FRA- - Type: BS-Ap. Date Filed 

From Inspector Place Date 

Railroad(s) filing application: 

Inspection: Date Location Railroad and other representatives

 

 

Furnish the following information: 

(a) Description of proposed changes or relief sought, location with respect to place and operating 

division, and mileage between designated places is correctly stated in the public notice ( ), or should 

be changed to read as follows ( ): 

(b) Name of any other railroads affected by the proposed changes not shown in public notice and 

manner in which each is affected: 

(c) List of prints and any bulletins, orders, timetables, etc., obtained during the investigation: 

(d) 1. Brief description of existing installation and equipment. 

 2. Brief description of proposed changes or relief requested. 

 3. Information relative to proposed changes not fully described in the public notice. 

 4. Present and proposed method of operation, number of trains or other movements per day, 

 and the speed authorizations and restrictions. 

 5. Other pertinent facts and remarks. 

 (Use additional blank sheets, numbered la, lb, lc, etc.) 

 
235-16 

-2- 

 Docket No. FRA - -______ 

(Complete Items (e) and (f) in Block Signal Applications only) 

(e) 1. If any field work has been started, describe the nature of work performed to date. 

 2. If any of the proposed changes have been placed in service, give a description of such changes, 

 the date such changes were placed in service, and the reasons for making the changes before 

 approval of the application. 

(f) Will proposed changes conform to the Rules, Standards and Instructions? 

 If not, state the rule number and in what respect they fail to conform. 

(g) Inspector’s opinion: The proposed changes will: 

( ) Reduce protection and safety. 

 ( ) Provide adequate protection for existing operating conditions without materially reducing safety. 

 ( ) Maintain the existing protection and safety. 

 ( ) Increase protection and safety. 

 State reasons: 

(h) Inspector’s recommendation as to disposition of application. 

 State reasons: 

 ___________________ ___________ 

 Inspector 

 
235-17 

-3- 

Docket No. FRA - -______ 

 (i) S&TC regional supervisory specialist’s recommendation as to the disposition of the application. 

 

If different than the inspector’s; state reasons: 

__________________________________ 

S&TC Regional Supervisory Specialist 
236-1 

49 CFR Part 236 – Rules, Standards, and Instructions Governing the

Installation, Inspection, Maintenance, and Repair of Signal and Train

Control Systems, Devices, and Appliances

 § 236.0 Applicability, minimum requirements, and penalties. 

Subpart A – Rules and Instructions: All Systems 

General 

 § 236.1 Plans, where kept. 

 § 236.2 Grounds. 

 § 236.3 Locking of signal apparatus housings. 

 § 236.4 Interference with normal functioning of device. 

 § 236.5 Design of control circuits on closed circuit principle. 

 § 236.6 Hand-operated switch equipped with switch circuit controller. 

 § 236.7 Circuit controller operated by switch-and-lock movement. 

 § 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus. 

 § 236.9 Selection of circuits through indicating or annunciating instruments. 

 § 236.10 Electric locks, forced-drop type; where required. 

 § 236.11 Adjustment, repair, or replacement of component. 

 § 236.12 Spring switch signal protection; where required. 

 § 236.13 Spring switch; selection of signal control circuits through circuit controller. 

 § 236.14 Spring switch signal protection; requirements. 

 § 236.15 Timetable instructions. 

 § 236.16 Electric lock, main track releasing circuit. 

 § 236.17 Pipe for operating connections, requirements. 

 § 236.18 Software management control plan. 

 

Roadway Signals and Cab Signals

 § 236.21 Location of roadway signals. 

 § 236.22 Semaphore signal arm; clearance to other objects. 

 § 236.23 Aspects and indications. 

 § 236.24 Spacing of roadway signals. 

 § 236.25 [Reserved] 

 § 236.26 Buffing device, maintenance. 

Track Circuits

 § 236.51 Track circuit requirements. 

 § 236.52 Relayed cut-section. 

 § 236.53 Track circuit feed at grade crossing. 

 § 236.54 Minimum length of track circuit. 

 § 236.55 Dead section; maximum length. 

 § 236.56 Shunting sensitivity. 

 § 236.57 Shunt and fouling wires. 

 § 236.58 Turnout, fouling section. 

 § 236.59 Insulated rail joints. 
236-2 

 § 236.60 Switch shunting circuit; use restricted. 

Wires and Cables

 § 236.71 Signal wires on pole line and aerial cable. 

 § 236.72 [Reserved] 

 § 236.73 Open-wire transmission line; clearance to other circuits. 

 § 236.74 Protection of insulated wire; splice in underground wire. 

 § 236.75 [Reserved] 

 § 236.76 Tagging of wires and interference of wires or tags with signal apparatus. 

 

Inspections and Tests; All Systems

 § 236.101 Purpose of inspection and tests; removal from service of relay or device failing to 

meet test requirements. 

 § 236.102 Semaphore or searchlight signal mechanism. 

 § 236.103 Switch circuit controller or point detector. 

 § 236.104 Shunt fouling circuit. 

 § 236.105 Electric lock. 

 § 236.106 Relays. 

 § 236.107 Ground tests. 

 § 236.108 Insulation resistance tests, wires in trunking and cables. 

 § 236.109 Time releases, timing relays, and timing devices. 

 § 236.110 Results of tests. 

Subpart B – Automatic Block Signal Systems 

Standards

 § 236.201 Track circuit, control of signals. 

 § 236.202 Signal governing movements over hand-operated switch. 

 § 236.203 Hand-operated crossover between main tracks; protection. 

 § 236.204 Track signaled for movements in both directions, requirements. 

 § 236.205 Signal control circuits; requirements. 

 § 236.206 Battery or power supply with respect to relay; location. 

 § 236.207 Electric lock on hand-operated switch; control. 

Subpart C – Interlocking 

Standards

 § 236.301 Where signals shall be provided. 

 § 236.302 Track circuits and route locking. 

 § 236.303 Control circuits for signals, selection through circuit controller operated by switch 

points or by switch locking mechanism. 

 § 236.304 Mechanical locking or same protection effected by circuits. 

 § 236.305 Approach or time locking. 

 § 236.306 Facing-point lock or switch-and-lock movement. 

 § 236.307 Indication locking. 

 § 236.308 Mechanical or electric locking or electric circuits; requisites. 

 § 236.309 Loss of shunt protection; where required. 
236-3 

 § 236.310 Signal governing approach to home signal. 

 § 236.311 Signal control circuits, selection through track relays or devices functioning as 

track relays 

 and through signal mechanism contacts and time releases at automatic interlocking. 

 § 236.312 Movable bridge, interlocking of signal appliances with bridge devices. 

 § 236.313 [Reserved] 

 § 236.314 Electric lock for hand-operated switch or derail. 

Rules and Instructions

 § 236.326 Mechanical locking removed or disarranged; requirement for permitting train 

movements 

 through interlocking. 

 § 236.327 Switch, movable-point frog, or split-point derail. 

 § 236.328 Plunger of facing-point lock. 

 § 236.329 Bolt lock. 

 § 236.330 Locking dog of switch-and-lock movement. 

 § 236.331-236.333 [Reserved] 

 § 236.334 Point detector. 

 § 236.335 Dogs, stops, and trunnions of mechanical locking. 

 § 236.336 Locking bed. 

 § 236.337 Locking faces of mechanical locking; fit. 

 § 236.338 Mechanical locking required in accordance with locking sheet and dog chart. 

 § 236.339 Mechanical locking; maintenance requirements. 

 § 236.340 Electromechanical locking machine; locking between electrical and mechanical 

levers. 

 § 236.341 Latch shoes, rocker links, and quadrants. 

 § 236.342 Switch circuit controller. 

 

Inspection and Tests

 § 236.376 Mechanical locking. 

 § 236.377 Approach locking. 

 § 236.378 Time locking. 

 § 236.379 Route locking. 

 § 236.380 Indication locking. 

 § 236.381 Traffic locking. 

 § 236.382 Switch obstruction test. 

 § 236.383 Valve locks, valves, and valve magnets. 

 § 236.384 Cross protection. 

 § 236.385 [Reserved] 

 § 236.386 Restoring feature on power switches. 

 § 236.387 Movable bridge locking. 

Subpart D – Traffic Control Systems 

Standards

 § 236.401 Automatic block signal system and interlocking standards applicable to traffic 

control systems. 
236-4 

 § 236.402 Signals controlled by track circuits and control operator. 

 § 236.403 Signals at controlled point. 

 § 236.404 Signals at adjacent controlled points. 

 § 236.405 Track signaled for movements in both directions, change of direction of traffic. 

 § 236.406 [Reserved] 

 § 236.407 Approach or time locking; where required. 

 § 236.408 Route locking. 

 § 236.409 [Reserved] 

 § 236.410 Locking, hand-operated switch; requirements. 

Rules and Instructions 

 § 236.426 Interlocking rules and instructions applicable to traffic control systems. 

Inspection and Tests

 § 236.476 Interlocking inspections and tests applicable to traffic control systems. 

Subpart E – Automatic Train Stop, Train Control, and Cab Signal Systems 

Standards 

 § 236.501 Forestalling device and speed control. 

 § 236.502 Automatic brake application; initiation by restrictive block conditions stopping 

distance in advance. 

 § 236.503 Automatic brake application; initiation when predetermined rate of speed 

exceeded. 

 § 236.504 Operation interconnected with automatic block signal system. 

 § 236.505 Proper operative relation between parts along roadway and parts on locomotive. 

 § 236.506 Release of brakes after automatic application. 

 § 236.507 Brake application; full service. 

 § 236.508 Interface with application of brakes by means of brake valve. 

 § 236.509 Two or more locomotives coupled. 

 § 236.510 [Reserved] 

 § 236.511 Cab signals controlled in accordance with block conditions stopping distance in 

advance. 

 § 236.512 Cab signal indication when locomotive enters block where restrictive conditions 

obtain. 

 § 236.513 Audible indicator. 

 § 236.514 Interconnection of cab signal system with roadway signal system. 

 § 236.515 Visibility of cab signals. 

 § 236.516 Power supply. 

 

Rules and Instructions; Roadway

 § 236.526 Roadway element not functioning properly. 

 § 236.527 Roadway element insulation resistance. 

 § 236.528 Restrictive condition resulting from open hand-operated switch; requirement. 

 § 236.529 Roadway element inductor; height and distance from rail. 

 § 236.530 [Reserved] 

 § 236.531 Trip arm; height and distance from rail. 
236-5 

 § 236.532 Strap iron inductor; use restricted. 

 § 236.533 [Reserved] 

 § 236.534 Entrance to equipped territory; requirements. 

 

Rules and Instructions; Locomotives

 § 236.551 Power supply voltage; requirement. 

 § 236.552 Insulation resistance; requirement. 

 § 236.553 Seal; where required. 

 § 236.554 Rate of pressure reduction; equalizing reservoir or brake pipe. 

 § 236.555 Repaired or rewound receiver coil. 

 § 236.556 Adjustment of relay. 

 § 236.557 Receiver; location with respect to rail. 

 § 236.558-236.559 [Reserved] 

 § 236.560 Contact element, mechanical trip type; location with respect to rail. 

 § 236.561 [Reserved] 

 § 236.562 Minimum rail current required. 

 § 236.563 Delay time. 

 § 236.564 Acknowledging time. 

 § 236.565 Provision made for preventing operation of pneumatic brake-applying apparatus 

by double-heading cock; requirement. 

 § 236.566 Locomotive of each train operating in automatic train stop, train control, or cab 

signal territory; equipped. 

 § 236.567 Restrictions imposed when device fails and/or is cut out en route. 

 § 236.568 Difference between speeds authorized by roadway signal and cab signal; action 

required. 

 

Inspection and Tests; Roadway

 § 236.576 Roadway element. 

 § 236.577 Test, acknowledgement, and cut-in circuits. 

 

Inspection and Tests; Locomotive

 § 236.586 Daily or after trip test. 

 § 236.587 Departure test. 

 § 236.588 Periodic test. 

 § 236.589 Relays. 

 § 236.590 Pneumatic apparatus. 

Subpart F – Dragging Equipment and Slide Detectors and Other Similar Protective 

Devices 

Standards

 § 236.601 Signals controlled by devices; location. 

Subpart G – Definitions

 § 236.700 Definitions. 

 § 236.701 Application, brake; full service. 

 § 236.702 Arm, semaphore. 

 § 236.703 Aspect. 
236-6 

 § 236.704 [Reserved] 

 § 236.705 Bar, locking. 

 § 236.706 Bed, locking. 

 § 236.707 Blade, semaphore. 

 § 236.708 Block. 

 § 236.709 Block, absolute. 

 § 236.710 Block, latch. 

 § 236.711 Bond, rail joint. 

 § 236.712 Brake pipe. 

 § 236.713 Bridge, movable. 

 § 236.714 Cab. 

 § 236.715-236.716 [Reserved] 

 § 236.717 Characteristics, operating. 

 § 236.718 Chart, dog. 

 § 236.719 Circuit, acknowledgment. 

 § 236.720 Circuit, common return. 

 § 236.721 Circuit, control. 

 § 236.722 Circuit, cut-in. 

 § 236.723 Circuit, double wire; line. 

 § 236.724 Circuit, shunt fouling. 

 § 236.725 Circuit, switch shunting. 

 § 236.726 Circuit, track. 

 § 236.727 Circuit, track; coded. 

 § 236.728 Circuit, trap. 

 § 236.729 Cock, double-heading. 

 § 236.730 Coil, receiver. 

 § 236.731 Controller, circuit. 

 § 236.732 Controller, circuit; switch. 

 § 236.733 Current, foreign. 

 § 236.734 Current of traffic. 

 § 236.735 Current, leakage. 

 § 236.736 Cut-section. 

 § 236.737 Cut-section, relayed. 

 § 236.738 Detector, point. 

 § 236.739 Device, acknowledging. 

 § 236.740 Device, reset. 

 § 236.741 Distance, stopping. 

 § 236.742 Dog, locking. 

 § 236.743 Dog, swing. 

 § 236.744 Element, roadway. 

 § 236.745 Face, locking. 

 § 236.746 Feature, restoring. 

 § 236.747 Forestall. 

 § 236.748 [Reserved] 

 § 236.749 Indication. 

 § 236.750 Interlocking, automatic. 

 § 236.751 Interlocking, manual. 
236-7 

 § 236.752 Joint, rail, insulated. 

 § 236.753 Limits, interlocking. 

 § 236.754 Line, open wire. 

 § 236.755 Link, rocker. 

 § 236.756 Lock, bolt. 

 § 236.757 Lock, electric. 

 § 236.758 Lock, electric, forced-drop. 

 § 236.759 Lock, facing-point. 

 § 236.760 Locking, approach. 

 § 236.761 Locking, electric. 

 § 236.762 Locking, indication. 

 § 236.763 Locking, latch-operated. 

 § 236.764 Locking, lever-operated. 

 § 236.765 Locking, mechanical. 

 § 236.766 Locking, movable bridge. 

 § 236.767 Locking, route. 

 § 236.768 Locking, time. 

 § 236.769 Locking, traffic. 

 § 236.770 Locomotive. 

 § 236.771 Machine, control. 

 § 236.772 Machine, interlocking. 

 § 236.773 Movements, conflicting. 

 § 236.774 Movement, facing. 

 § 236.775 Movement, switch-and-lock. 

 § 236.776 Movement, trailing. 

 § 236.777 Operator, control. 

 § 236.778 Piece, driving. 

 § 236.779 Plate, top. 

 § 236.780 Plunger, facing-point lock. 

 § 236.781 [Reserved] 

 § 236.782 Point, controlled. 

 § 236.783 Point, stop indication. 

 § 236.784 Position, deenergized. 

 § 236.785 Position, false restrictive. 

 § 236.786 Principle, closed circuit. 

 § 236.787 Protection, cross. 

 § 236.787a Railroad. 

 § 236.788 Receiver. 

 § 236.789 Relay, timing. 

 § 236.790 Release, time. 

 § 236.791 Release, value. 

 § 236.792 Reservoir, equalizing. 

 § 236.793 Rod, lock. 

 § 236.794 Rod, up-and-down. 

 § 236.795 Route. 

 § 236.796 Routes, conflicting. 

 § 236.797 Route, interlocked. 
236-8 

 § 236.798 Section, dead. 

 § 236.799 Section, fouling. 

 § 236.800 Sheet, locking. 

 § 236.801 Shoe, latch. 

 § 236.802 Shunt. 

 § 236.802a Siding. 

 § 236.803 Signal, approach. 

 § 236.804 Signal, block. 

 § 236.805 Signal, cab. 

 § 236.806 Signal, home. 

 § 236.807 Signal, interlocking. 

 § 236.808 Signals, opposing. 

 § 236.809 Signal, slotted mechanical. 

 § 236.810 Spectacle, semaphore arm. 

 § 236.811 Speed, medium. 

 § 236.812 Speed, restricted. 

 § 236.813 Speed, slow. 

 § 236.813a State, most restrictive. 

 § 236.814 Station, control. 

 § 236.815 Stop. 

 § 236.816 Superiority of trains. 

 § 236.817 Switch, electro-pneumatic. 

 § 236.818 Switch, facing-point. 

 § 236.819 Switch, hand-operated. 

 § 236.820 Switch, interlocked. 

 § 236.820a Switch, power-operated. 

 § 236.821 Switch, sectionalizing. 

 § 236.822 Switch, spring. 

 § 236.823 Switch, trailing-point. 

 § 236.824 System, automatic block signal. 

 § 236.824a System, automatic cab signal. 

 § 236.825 System, automatic train control. 

 § 236.826 System, automatic train stop. 

 § 236.827 System, block signal. 

 § 236.828 System, traffic control. 

 § 236.829 Terminal, initial. 

 § 236.830 Time, acknowledging. 

 § 236.831 Time, delay. 

 § 236.831a Track, main. 

 § 236.832 Train. 

 § 236.833 Train, opposing. 

 § 236.834 Trip. 

 § 236.835 Trunking. 

 § 236.836 Trunnion. 

 § 236.837 Valve, electro-pneumatic. 

 § 236.838 Wire, shunt. 
236-9 

Subpart H – Standards for Processor-Based Signal and Train Control Systems 

 § 236.901 Purpose and scope. 

 § 236.903 Definitions. 

 § 236.905 Railroad Safety Program Plan (RSPP). 

 § 236.907 Product Safety Plan (PSP). 

 § 236.909 Minimum performance standard. 

 § 236.911 Exclusions. 

 § 236.913 Filing and approval of PSPs. 

 § 236.915 Implementation and operation. 

 § 236.917 Retention of records. 

 § 236.919 Operations and Maintenance Manual. 

 § 236.921 Training and qualification program, general. 

 § 236.923 Task analysis and basic requirements. 

 § 236.925 Training specific to control office personnel. 

 § 236.927 Training specific to locomotives engineers and other operating personnel. 

 § 236.929 Training specific to roadway workers. 

Subpart I – Positive Train Control Systems 

 § 236.1001 Purpose and scope. 

 § 236.1003 Definitions. 

 § 236.1005 Requirements for Positive Train Control systems. 

 § 236.1006 Equipping locomotives operating in PTC territory. 

 § 236.1007 Additional requirements for high-speed service. 

 § 236.1009 Procedural requirements. 

 § 236.1011 PTC Implementation Plan content requirements. 

 § 236.1013 PTC Development Plan and Notice of Product Intent content requirements and 

Type Approval. 

 § 236.1015 PTC Safety Plan content requirements and PTC System Certification. 

 § 236.1017 Independent third party Verification and Validation. 

 § 236.1019 Main line track exceptions. 

 § 236.1020 Exclusion of track segments for implementation due to cessation of PIH materials 

service or rerouting. 

 § 236.1021 Discontinuances, material modifications, and amendments. 

 § 236.1023 Errors and malfunctions. 

 § 236.1025 [Reserved] 

 § 236.1027 PTC system exclusions. 

 § 236.1029 PTC system use and en route failures. 

 § 236.1031 Previously approved PTC systems. 

 § 236.1033 Communications and security requirements. 

 § 236.1035 Field testing requirements. 

 § 236.1037 Records retention. 

 § 236.1039 Operations and Maintenance Manual. 

 § 236.1041 Training and qualification program, general. 

 § 236.1043 Task analysis and basic requirements. 

 § 236.1045 Training specific to office control personnel. 

 § 236.1047 Training specific to locomotive engineers and other operating personnel. 

 § 236.1049 Training specific to roadway workers. 
236-10 

Appendix A to Part 236 – Civil Penalty Schedule – refer to 49 CFR 

Appendix B to Part 236 – Risk Assessment Criteria 

Appendix C to Part 236 – Safety Assurance Criteria and Processes 

Appendix D to Part 236 – Independent Review of Verification and Validation 

Appendix E to Part 236 – Human-Machine Interface (HMI) Design 

Appendix F to Part 236 – Minimum Requirements of FRA Directed Independent Third-Party 

Assessment of PTC System Safety Verification and Validation 

Added for ready reference: 

Reference A - FRA – Fouling Section Clearance Point Measurement Diagram 

Reference B - FRA – Copy of January 3, 1985, Himmel Letter 

Reference C - FRA – Signal Related Technical Bulletins and Safety Advisories 
236-11 

§ 236.0 Applicability, minimum requirements, and penalties. 

 (a) Except as provided in paragraph (b) of this section, this part applies to all railroads. 

 (b) This part does not apply to- 

 (1) A railroad that operates only on track inside an installation that is not part of the general 

railroad system of transportation; or 

 (2) Rapid transit operations in an urban area that are not connected to the general railroad 

system of transportation. 

 (c)(1) Prior to January 17, 2012, where a passenger train is operated at a speed of 60 or more 

miles per hour, or a freight train is operated at a speed of 50 or more miles per hour- 

 (i) A block signal system complying with the provisions of this part shall be installed; or, 

 (ii) A manual block system shall be placed permanently in effect that shall conform to the 

following conditions: 

 (A) A passenger train shall not be admitted to a block occupied by another train except when 

absolutely necessary and then only by operating at restricted speed; 

 (B) No train shall be admitted to a block occupied by a passenger train except when 

absolutely necessary and then only by operating at restricted speed; 

 (C) No train shall be admitted to a block occupied by an opposing train except when 

absolutely necessary and then only while one train is stopped and the other is operating at 

restricted speed; and 

 (D) A freight train, including a work train, may be authorized to follow a freight train, 

including a work train, into a block and then only when the following train is operating at 

restricted speed. 

 (2) On and after January 17, 2012, where a passenger train is permitted to operate at a speed 

of 60 or more miles per hour, or a freight train is operated at a speed of 50 or more miles per 

hour, a block signal system complying with the provisions of this part shall be installed, unless 

an FRA approved PTC system meeting the requirements of this part for the subject speed and 

other operating conditions is installed. 

 (d)(1) Prior to December 31, 2015, where any train is permitted to operate at a speed of 80 or 

more miles per hour, an automatic cab signal, automatic train stop, or automatic train control 

system complying with the provisions of this part shall be installed, unless an FRA approved 

PTC system meeting the requirements of this part for the subject speed and other operating 

conditions, is installed. 

 (2) On and after December 31, 2015, where any train is permitted to operate at a speed of 80 

or more miles per hour, a PTC system complying with the provisions of subpart I shall be 

installed and operational, unless FRA approval to continue to operate with an automatic cab 

signal, automatic train stop, or automatic train control system complying with the provisions of 

this part has been justified to, and approved by, the Associate Administrator. 

 (3) Subpart H of this part sets forth requirements for voluntary installation of PTC systems, 

and subpart I of this part sets forth requirements for mandated installation of PTC systems, each 

under conditions specified in their respective subpart. 

 (e) Nothing in this section authorizes the discontinuance of a block signal system, 

interlocking, traffic control system, automatic cab signal, automatic train stop, or automatic train 

control system, or PTC system, without approval by the FRA under part 235 of this title. 

However, a railroad may apply for approval of discontinuance or material modification of a 

signal or train control system in connection with a request for approval of a Positive Train 

Control Development Plan (PTCDP) or Positive Train Control Safety Plan (PTCSP) as provided 

in subpart I of this part. 

 (f) Any person (an entity of any type covered under 1 U.S.C. 1, including but not limited to 

the following: a railroad; a manager, supervisor, official, or other employee or agent of a 
236-12 

railroad; any owner, manufacturer, lessor, or lessee of railroad equipment, track, or facilities; any 

independent contractor providing goods or services to a railroad; and any employee of such 

owner, manufacturer, lessor, lessee, or independent contractor) who violates any requirement of 

this part or causes the violation of any such requirement is subject to a civil penalty of at least 

$650 and not more than $25,000 per violation, except that: Penalties may be assessed against 

individuals only for willful violations, and, where a grossly negligent violation or a pattern of 

repeated violations has created an imminent hazard of death or injury to persons, or has caused 

death or injury, a penalty not to exceed $100,000 per violation may be assessed. Each day a 

violation continues shall constitute a separate offense. See appendix A to this part for a 

statement of agency civil penalty policy. 

 (g) A person may also be subject to criminal penalties for knowingly and willfully making a 

false entry in a record or report required to be made under this part, filing a false record or report, 

or violating any of the provisions of 49 U.S.C. 21311. 

 (h) The requirements of subpart H of this part apply to safety-critical processor-based signal 

and train control systems, including subsystems and components thereof, developed under the 

terms and conditions of that subpart. 

 (i) Preemptive effect. (1) Under 49 U.S.C. 20106, issuance of these regulations preempts any 

state law, regulation, or order covering the same subject matter, except an additional or more 

stringent law, regulation, or order that is necessary to eliminate or reduce an essentially local 

safety or security hazard; is not incompatible with a law, regulation, or order of the United States 

Government; and that does not impose an unreasonable burden on interstate commerce. 

 (2) This part establishes federal standards of care for railroad signal and train control 

systems. This part does not preempt an action under state law seeking damages for personal 

injury, death, or property damage alleging that a party has failed to comply with the federal 

standard of care established by this part, including a plan or program required by this part. 

Provisions of a plan or program which exceed the requirements of this part are not included in 

the federal standard of care. 

 (3) Under 49 U.S.C. 20701-20703, issuance of these regulations preempts the field of 

locomotive safety, extending to the design, the construction, and the material of every part of the 

locomotive and tender and all appurtenances thereof. 

Application: 

This section specifies that the RS&I apply to each railroad that operates on standard gauge which 

is part of the general system of railroad transportation. Further, this section also prescribes the 

criteria requiring the installation of block signal systems, automatic train stop, train control, or 

cab signal systems. 

This rule requires that a block signal system, complying with the provisions of Part 236, or prior 

to January 17, 2012, a manual block system complying with the provisions of this section, be 

installed where passenger trains are permitted to operate at 60 mph or more, or freight trains are 

permitted to operate at 

50 mph or more. On and after January 17, 2012, a manual block system is no longer accepted as 

allowing passenger trains to operate at 60 mph or more, or freight trains to operate at 50 mph or 

more. In such instances, a block signal system complying with the provisions of Part 236 shall 

be installed, unless an FRA approved PTC system meeting the requirements of Part 236 for the 

subject speed and other operating conditions is installed. Further, prior to December 31, 2015, 

an automatic train stop, train control, or cab signal system shall be installed where any train 

operates at 80 mph or more. On and after December 31, 2015, where any train is permitted to 

operate at a speed of 80 mph or more, a PTC system complying with the provisions of Subpart I 
236-13 

shall be installed and operational, unless FRA approval to continue to operate with an automatic 

cab signal, automatic train stop, or automatic train control system complying with the provisions 

of this part has been justified to, and approved by, the Associate Administrator. 

This section details how a manual block system shall operate, and requires that the system be 

permanently in effect, i.e., all trains must be operated by manual block system rules. 

A manual block system is a method of train operation by mandatory directives or voice rules, in 

nonsignaled territory (or against current of traffic), which authorizes movements between 

defined limits or blocks, and conforms with §§ 236.0(c)(1)(ii)(A), (B), (C), and (D). 

The individual operating rules of a carrier will determine if the method of operation conforms to 

a manual block system. 

Note: A methodology such as the track warrant control rules of some carriers, which permit and 

establish yard limits within designated blocks, does not conform to the above manual block 

system requirements because trains are permitted to enter the main track within designated yard 

limit areas without direct authority or regard for block occupancy. 

This section does not authorize the discontinuance of any signal system without FRA approval 

being obtained through the processes prescribed in § 236.0(e). 

 

CLASSIFICATION OF DEFECT CODES

236.0.C1 Block signal system not installed on line where freight train operates at 50 mph or 

more. 

236.0.C2 Block signal system not installed on line where passenger train operates at 60 mph or 

more. 

236.0.C3 Manual block system permits a passenger train to be admitted into a block occupied 

by another train where not absolutely necessary and then only by operating at 

restricted speed. 

236.0.C4 Manual block system permits a train to be admitted into a block occupied by a 

passenger train where not absolutely necessary and then only by operating at 

restricted speed. 

236.0.C5 Manual block system permits a train to be admitted into a block occupied by an 

opposing train where not absolutely necessary and then only while one train is 

stopped and the other is operating at restricted speed. 

236.0.C6 Manual block system permits a freight train to enter into a block occupied by a 

preceding freight train in excess of restricted speed. 

236.0.C7 Prior to December 31, 2015, an automatic cab signal, automatic train stop, automatic 

train control, or FRA approved PTC system is not installed where a train is permitted 

to operate at 80 mph or more. 

236.0.C8 On or after December 31, 2015, a PTC system is not installed, unless FRA approval 
236-14 

to continue to operate with an automatic cab signal, automatic train stop, or automatic 

train control system is obtained, where a train is permitted to operate at 80 mph or 

more. 

Subpart A – Rules and Instructions: All Systems 

General

§ 236.1 Plans, where kept.

 As required for maintenance, plans shall be kept at all interlockings, automatic signals, and 

controlled points. Plans shall be legible and correct.

Application: 

Plans are necessary for the installation, inspection, maintenance, and repair of signal systems and 

are required to be correct and legible. 

The track layout plan, circuit plan including circuits to approach signals, and locking sheet and 

dog chart where mechanical locking is used, shall be kept at each interlocking. 

The circuit plan including circuits to approach signals shall be kept at each controlled point. 

Circuit plans shall be kept at each automatic signal in automatic block signal territory, traffic 

control territory, automatic train stop, train control, or signal territory in other systems such as 

spring switch protection, slide protection, etc. 

Plans are required to be legible and correct. Plans that are torn, faded, or those having 

experienced more than one change in colored pencil are not considered to be legible and correct. 

If more than one set of plans are at a location, they all must be legible and correct or the 

noncompliant sets must be corrected or removed. 

CLASSIFICATION OF DEFECTS

236.1.A1 Track layout plan not kept at interlocking. 

236.1.A2 Circuit plan not kept at interlocking. 

236.1.A3 Locking sheet and dog chart not kept at interlocking where mechanical locking is 

 used. 

236.1.A4 Circuit plan not kept at controlled point. 

236.1.A5 Circuit plan not kept at automatic signal. 

236.1.A6 Track layout plan for interlocking not correct. 

236.1.A7 Circuit plan for interlocking not correct. 
236-15 

236.1.A8 Locking sheet and dog chart for interlocking where mechanical locking is used not 

 correct. 

236.1.A9 Circuit plan for controlled point not correct. 

236.1.A10 Circuit plan for automatic signal not correct. 

236.1.A11 Profile plan not correct. (Includes plan not drawn to scale or not showing location of 

 all signals, grades, and alignment). 

236.1.A12 Track layout plan for interlocking not legible. 

236.1.A13 Circuit plan for interlocking not legible. 

236.1.A14 Locking sheet and dog chart for interlocking not legible. 

236.1.A15 Circuit plan for controlled point not legible. 

236.1.A16 Circuit plan for automatic signal not legible. 

236.1.A17 Profile plan not legible. 

236.1.A18 Profile plan not available. 

§ 236.2 Grounds. 

 Each circuit, the functioning of which affects the safety of train operations, shall be kept free 

of any ground or combination of grounds which will permit a flow of current equal to or in 

excess of 75 percent of the release value of any relay or other electromagnetic device in the 

circuit, except circuits which include any track rail and except the common return wires of 

single-wire, single-break, signal control circuits using a grounded common, and alternating 

current power distribution circuits which are grounded in the interest of safety.

Application: 

Vital circuits shall be kept free of grounds equal to or in excess of 75 percent of the release value 

of relay or electromagnetic device in circuits. Track circuits, common return wires of singlewire, single-break signal control circuits grounded by design, and alternating current power 

distribution circuits grounded in the interest of safety are excluded. 

Vital circuits designed to be ground free are required to be kept free of any ground current equal 

to or in excess of 75 percent of the release value of any relay or electromagnetic device in the 

circuit. There is no difference between an accidental or intentional ground. 

Electronic devices designed to be ground free shall be kept free of grounds having a value that 

affects the proper functioning of the device. (See Technical Bulletin S-99-03)

Extreme care shall be exercised when testing for grounds. The carrier employee shall perform 

the testing. Testing shall not be conducted while trains are approaching or passing, and the meter 

shall be watched at all times. If the meter indicates the energization of a relay, the meter shall be 
236-16 

immediately disconnected. An unobserved meter shall never be left connected to a vital circuit 

and ground. 

Ground test shall be performed at every instrument case or house inspected. The preliminary test 

shall be with a voltmeter connected from the line or track arrestor ground to a track circuit which 

will prove the meter is operating and the integrity of the ground circuit. 

AC power shall be interrupted during tests in order to check AC lighting circuits having DC 

standby. 

These requirements apply to highway-rail grade crossing warning devices, dragging equipment 

protection, slide detectors, etc., where signal control circuits are selected through relays 

energized by the power supply of such protection. 

The railroad should take prompt action to correct a ground. 

CLASSIFICATION OF DEFECTS

236.2.A1 Circuit grounded sufficiently to permit flow of current equal to or in excess of 75 

percent of the release value of relay or other electromagnetic device in circuit. 

236.2.A2 Circuit grounded sufficiently to affect the proper functioning of electronic device. 

§ 236.3 Locking of signal apparatus housings.

 Signal apparatus housings shall be secured against unauthorized entry.

Application: 

Housings of signal apparatus shall be secured to prevent unauthorized entry. 

All outdoor housing of mechanical or power-operated devices used to operate signal or 

interlocked units must be kept locked, sealed, or secured. This includes signal cases, instrument 

cases, switch circuit controllers, facing-point locks, switch machines, junction or terminal boxes 

and battery boxes. 

Power interlocking machine cabinets shall be locked or sealed to such extent that entry to or 

manipulation of the devices contained in the cabinet can only be accomplished by unlocking the 

lock or breaking the seal. 

Time release and exposed electric locks must be locked or sealed. 

Cabinets or cases containing apparatus designed to release locking in emergencies shall be 

locked or sealed. 

Wrench or nut-locking with bell is acceptable. 

CLASSIFICATION OF DEFECTS

236.3.A1 Signal case or housing not secured against unauthorized entry. 
236-17 

236.3.A2 Instrument case not secured against unauthorized entry. 

236.3.A3 Power interlocking machine cabinet not secured against unauthorized entry. 

236.3.A4 Time release not secured against unauthorized entry. 

236.3.A5 Exposed electric lock not secured against unauthorized entry.

§ 236.4 Interference with normal functioning of device.

 The normal functioning of any device shall not be interfered with in testing or otherwise 

without first taking measures to provide for safety of train operation which depends on normal 

functioning of such device. 

Application: 

Safety of train operation must be provided before interfering with the normal functioning of any 

device. 

The intent of this rule is to ensure that carriers maintain the integrity of signal systems by 

prohibiting procedures or practices that defeat or nullify the minimum requirements of the RS&I. 

Interference is any condition that circumvents, hinders, impedes, or diminishes whatsoever the 

intended protection of a device and may be accomplished by testing, installing, repairing, 

replacing, operating, or manipulating a signal component indicating or affecting the indication of 

safe passage for trains. There is no difference between accidental or intentional interference with 

respect to the enforcement of this rule. 

Tests of signal equipment should not be conducted until it has been ascertained that no train 

movements will be affected. No test should be conducted during the passage of a train, hi-rail 

vehicle, or motor car. 

Areas where interference can occur include all components, devices, mechanisms, or apparatus 

in vital circuits including shunt and fouling wires of switches and turnouts. 

Unless measures are taken to provide safety of train operation, the following are some examples 

of interference with various types of equipment and procedures: 

1. Testing such as falsely energizing relays, jumpering contacts, turning relays upside down; 

operating hand-operated switch, adjusting switch circuit controller or shunt fouling 

circuit, in advance of approaching train; operating power-operated switch without 

permission of dispatcher or operator; performing ground tests while train is approaching 

or moving over power-operated switch; defeating predetermined time interval of time 

release or time relay; and release of electric or mechanical locking. 

2. Performing efficiency tests by removal of a signal lamp bulb while not providing an 

approach indication to the darkened signal; or placing a shunt in advance of a signal after 

a train has passed its approach signal. 

3. At interlockings, the unnecessary breaking of seals to force indications, defeat time, or 

approach or route locking requirements. Note: The procedure to move trains through 
236-18 

interlockings under flag protection and appropriate rules is not considered interference. 

4. Defeat of protective features to avoid train delay or to expedite train movements such as 

disconnecting shunt or fouling wires, turning relays upside down, jumpering contacts, 

falsely energizing relays or circuits, or releasing electrical locking. 

The following will be considered interference under all circumstances: 

Performing repairs and replacements of equipment or apparatus such as relays, cables, and 

conductors without proper testing afterwards; replacing rails in shunt fouling circuits leaving 

fouling wires and rail bonds broken and disconnected; replacing ties under switch machines or 

switch circuit controllers and leaving the circuit controller improperly adjusted; and leaving a 

switch in mid-stroke position. 

CLASSIFICATION OF DEFECTS

236.4.A1 Interference with normal functioning of device without taking measures to provide 

for safety of train operation. 

Excerpt from letter of January 3, 1985 

From: FRA Associate Administrator, Mr. J. W. Walsh 

To: Mr. L. M. Himmel, Sr., Executive Director 

Communications and Signal Division, AAR

Section 236.4 Interference with normal functioning of device.

The AAR requested that during operational tests of locomotive engineers, a 

signal made dark without establishing an approach aspect not be considered as 

interference. The AAR recommends that FRA’s Technical Manual be revised 

to make the requirements of this rule applicable only at controlled points and 

automatic interlockings. 

This rule imposes on each carrier the requirement to prohibit procedures or 

practices which defeat or nullify the safety of its signal systems without first 

taking measures to provide for the safety of train operations. 

The comments of the AAR clearly indicated that a dark signal is regarded as 

the most restrictive indication that can be given at that signal and that an 

engineer is required to act on the preview of the dark signal to reduce train 

speed or stop in compliance with the restrictive indication. 

Section 236.23 requires that a yellow light, a lunar light, or a series of lights or 

a semaphore blade in the upper or lower quadrant at an angle of 45 degrees to 

the vertical be used to indicate that speed is to be restricted and stop may be 

required. 

The FRA cannot condone a practice that is hazardous to the safety of train 

operation or that is contrary to its regulations. Accordingly, an aspect 

complying with § 236.23 is required in approach to any signal made dark for 

operational tests. 
236-19 

§ 236.5 Design of control circuits on closed circuit principle.

 All control circuits the functioning of which affects safety of train operation shall be 

designed on the closed circuit principle, except circuits for roadway equipment of intermittent 

automatic train stop system.

Application: 

This rule requires that control circuits which affect the safety of train operation be designed on 

the closed circuit principle. 

This rule excludes circuits for roadway equipment of intermittent automatic train-stop systems, 

shunt fouling circuits, and normally open track circuits on auxiliary tracks used to approach light 

wayside signals. 

This rule includes all vital circuits and track circuits through which signal control circuits are 

selected. 

Circuits should be so designed that failure of any part or component of the circuit will cause 

signals to display their most restrictive aspects. 

CLASSIFICATION OF DEFECTS

236.5.A1 Control circuit, the function of which affects safety of train operation, not designed 

on closed circuit principle. 

§ 236.6 Hand-operated switch equipped with switch circuit controller.

 Hand-operated switch equipped with switch circuit controller connected to the point, or with 

facing-point lock and circuit controller, shall be so maintained that when point is open one-fourth 

inch or more on facing-point switch and three-eighths inch or more on trailing-point switch, 

track or control circuits will be opened or shunted or both, and if equipped with facing-point lock 

with circuit controller, switch cannot be locked. On such hand-operated switch, switch circuit 

controllers, facing-point locks, switch-and-lock movements, and their connections shall be 

securely fastened in place, and contacts maintained with an opening of not less than onesixteenth inch when open.

Application: 

A hand-operated switch equipped with switch circuit controller connected to the point, or handoperated switch equipped with facing-point lock and circuit controller, is required to shunt track 

circuit or open control circuits, or both, when the point is open one-fourth inch or more on 

facing-point switch and three-eighths inch or more on trailing-point switch. The facing-point 

lock shall be so adjusted that it cannot be locked when point is so opened. Switch circuit 

controllers, facing-point locks, and switch-and-lock movements, and their connections must be 

securely fastened in place. 

Contacts must open at least one-sixteenth inch when the contacts are fully open. Where switch 

circuit controller is connected to the point, the switch circuit controller shall be connected to the 
236-20 

normally closed switch point. 

FRA has in the past and will continue to require each switch circuit controller to be connected to 

the switch point over which train movements are governed by signal indications. The use of a 

rigid front rod can meet this requirement in instances where signal indication is provided over 

the switch in either position. 

This rule does not apply to power-operated switches, spring switches, or to the electric lock 

mechanisms on hand-operated switches. 

A test should be made by placing the appropriate gage between the point and stock rail, 6 inches 

from the end of the point, and applying pressure against the gage until it cannot be removed. 

Where control circuits are opened through switch circuit controller or through switch repeating 

relay, it is not a requirement that shunt wires be provided or that shunt wires be doubled. 

CLASSIFICATION OF DEFECTS

236.6.A1 Switch circuit controller on hand-operated facing-point switch not adjusted to shunt 

track circuit or open control circuits when switch point is open one-fourth inch or 

more. 

236.6.A2 Switch circuit controller on hand-operated trailing-point switch not adjusted to shunt 

track circuit or open control circuits when switch point is open three-eights inch or 

more. 

236.6.A3 Hand-operated facing-point switch equipped with facing-point lock and circuit 

controller can be locked when switch point is open one-fourth inch or more. 

236.6.A4 Hand-operated trailing-point switch equipped with facing-point lock and circuit 

controller can be locked when switch point is open three-eights inch or more. 

236.6.A5 Switch circuit controller not securely fastened in place. 

236.6.A6 Facing-point lock not securely fastened in place. 

236.6.A7 Switch-and-lock movement not securely fastened in place. 

236.6.A8 Contact opening of switch circuit controller contact less than one-sixteenth inch. 

236.6.A9 Switch circuit controller connections not securely fastened. 

236.6.A10 Switch-and-lock movement connections not securely fastened. 

236.6.A11 Facing-point lock connections not securely fastened. 

236.6.A12 Switch circuit controller not connected to normally closed switch point.
236-21 

§ 236.7 Circuit controller operated by switch-and-lock movement.

 Circuit controller operated by switch-and-lock movement shall be maintained so that 

normally open contacts will remain closed and normally closed contacts will remain open until 

the switch is locked.

Application:

Applies to hand-operated, mechanical, or power-operated switch-and-lock movements including 

such machines as models M-22, M-23, 5, 55, T-20, etc. Before locking bar is completely 

withdrawn from lock rod, normally closed contacts must open and normally open contacts must 

close and remain so until locking bar has again engaged lock rod. 

 

CLASSIFICATION OF DEFECTS

236.7.A1 Contacts of circuit controller operated by switch-and-lock movement not adjusted so 

that normally open contacts remain closed until the switch is locked. 

236.7.A2 Contacts of circuit controller operated by switch-and-lock movement not adjusted so 

that normally closed contacts remain open until the switch is locked. 

§ 236.8 Operating characteristics of electromagnetic, electronic, or electrical apparatus.

 Signal apparatus, the functioning of which affects the safety of train operation, shall be 

maintained in accordance with the limits within which the device is designed to operate.

Application: 

Operating characteristics of electromagnetic, electronic, or electrical apparatus in service shall be 

in accordance with the limits within which it is designed to operate. 

Rules 101, 102, 105, 106, 107, 108, 109, 551, 552, 588, and 589 address those devices so 

important to safety of train operation that periodic tests are required to ascertain that operating 

characteristics remain unchanged. 

Applies to all electromagnetic, electronic, or electrical devices used in or associated with vital 

circuitry or switch machine operation. 

Each carrier should have specifications setting forth the pick-up values, release values, working 

values, and condemning limits of these values for all electromagnetic, electronic, or electrical 

devices in use on its property. Some examples of deficient operating characteristics are: 

 Pick-up value too high. 

 Pick-up value too low. 

 Release value too high. 

 Release value too low. 

Manufacturer specifications or carrier standards compatible with manufacturer specifications 

shall be used to determine such values. 
236-22 

Some examples of electromagnetic devices covered by this rule not requiring periodic tests are: 

 Switch machine controllers. 

 Thermal relays of switch machine controllers. 

 Indicating magnets on interlocking machines. 

 Coils of forced-drop electric locks. 

CLASSIFICATION OF DEFECTS

236.8.A1 Pick-up value of electromagnetic device not in accordance with the limits within 

which it is designed to operate. 

236.8.A2 Drop-away value of electromagnetic device not in accordance with the limits within 

which is it designed to operate. 

236.8.A3 Working value of electronic or electrical apparatus not in accordance with the limits 

within which the apparatus is designed to operate. 

§ 236.9 Selection of circuits through indicating or annunciating instruments.

 Signal control and electric locking circuits shall not be selected through the contacts of 

instruments designed primarily for indicating or annunciating purposes in which an indicating 

element attached to the armature is arranged so that it can in itself cause improper operation of 

the armature.

Application: 

Signal control and electric locking circuits are required to be selected through contacts of safety 

relays. 

This rule does not prohibit the use of annunciating or indicating devices, but does prohibit 

selecting vital circuits through contacts operated by such devices. 

Some examples of annunciating or indicating devices are: 

a. Switch indicator 

b. Block indicator 

c. Cab indicator 

d. Approach indicator 

e. Track indicator 

f. OSing device 

g. Semaphore indicator 

h. Manually operated call-on device 

Test such devices that are in noncompliance by manually moving indicator to energized position 

and observing if armature and contacts are actuated. If so, contacts of such devices may not be 

used in vital circuitry. 
236-23 

CLASSIFICATION OF DEFECTS

236.9.A1 Signal control circuit selected through contacts of indicator or annunciator in which 

the indicating element attached to the armature is arranged so that it can in itself 

cause improper operation of the armature. 

236.9.A2 Electric locking circuit selected through contacts of indicator or annunciator in which 

the indicating element attached to the armature is arranged so that it can in itself 

cause improper operation of the armature. 

§ 236.10 Electric locks, forced-drop type; where required.

 Electric locks on new installations and new electric locks applied to existing installations 

shall be of the forced-drop type. 

Application: 

This rule requires that electric locks applied to new installations and new electric locks applied to 

existing installations be of the forced-drop type. 

This rule applies to all electric locks installed after October 1, 1950, on new locations. 

This rule applies to all electric locks on hand-operated switches and interlocking machines. 

Tests should be made to determine that the locking dog is forced down into the locking sector. 

This test can be made by observing movement of the locking dog as the switch lock is locked in 

normal position. 

Since most forced-drop type locks are spring loaded, they should be checked to determine that 

the spring is of sufficient strength so that normal operation does not release the locking dog 

unless the lock is energized. 

A non-forced-drop electric lock may be removed from service, repaired, and restored to service 

without replacing it with a forced-drop type electric lock. 

CLASSIFICATION OF DEFECTS

236.10.A1 Electric lock not forced-drop type. (Applies only to electric lock installed after 

October 1, 1950.) 

236.10.A2 New electric lock applied to existing installation not forced-drop type. 

§ 236.11 Adjustment, repair, or replacement of component.

 When any component of a signal system, the proper functioning of which is essential to the 

safety of train operation, fails to perform its intended signaling function or is not in 

correspondence with known operating conditions, the cause shall be determined and the faulty 

component adjusted, repaired, or replaced without undue delay.
236-24 

Application: 

This rule requires a carrier to determine the cause of a signal aspect that is not in accordance with 

known operating conditions and requires that a failed signaling component (which adversely 

affects safety of train operation) be adjusted, repaired, or replaced without undue delay. 

A signal aspect “not in correspondence with known operating conditions” means a signal aspect 

other than that intended by normal signal system operation. 

A carrier is required to determine the cause of each “Stop” or “Stop and Proceed” aspect 

resulting from an unknown condition. If that condition is the result of the failure of a signaling 

component and is a hazard to the safety of train operation, corrective action is required before the 

next train movement. Should train operation require nighttime or weekend corrections, they 

must be made. 

Conditions which cause false stop or false restrictive indications may cause inconvenience and 

additional expense to train movements. Examples of such conditions that do not necessarily 

pose a threat to safety of train operation are a burned out lamp, a broken track circuit connector, 

or a broken line wire. 

This rule applies to adjustable components which, when improperly adjusted, create safety 

hazards such as (1) circuit controller, point detector, and lock rod adjustments exceeding the 

requirements; 

(2) insufficient predetermined time intervals; and (3) excessive track circuit values. 

This rule applies to components which, if not repaired, create safety hazards such as (1) 

grounded circuits; (2) insecure circuit controllers, switch machines, pipeline carriers and cranks; 

and (3) bent, worn, or insecure connecting rods, lock rods, and point detector rods. 

This rule also applies to components which, if not replaced, create safety hazards such as (1) a 

broken connecting rod, lock rod, point detector rod, pipeline, or crank; (2) broken fouling wires, 

shunt wires, and bond wires in fouling circuit; and (3) defective relays, cable, and conductors. 

Test equipment and instruments are excluded. 

CLASSIFICATION OF DEFECTS

236.11.A1 Component, essential to the safety of train operation, failing to perform its 

intended function not adjusted without undue delay. 

236.11.A2 Component, essential to the safety of train operation, failing to perform its 

intended function not repaired without undue delay. 

236.11.A3 Component, essential to the safety of train operation, failing to perform its 

intended function not replaced without undue delay. 

236.11.A4 Cause not determined for signal component out of correspondence with known 

operating conditions. 
236-25 

§ 236.12 Spring switch signal protection, where required. 

 Signal protection shall be provided for facing and trailing movements through spring switch 

within interlocking limits and through spring switch installed in automatic block signal, train 

stop, train control or cab signal territory where train movements over the switch are made at a 

speed exceeding 20 miles per hour, except that signal protection shall be required only with the 

current of traffic on track signaled for movement in only one direction. 

 Note: Does not apply to spring switch installed prior to October 1, 1950, in automatic block 

signal, automatic train stop, or automatic train control territory.

Application: 

This rule prescribes signal protection for spring switches in interlockings and for spring switches 

installed after October 1, 1950, in automatic block signal, train stop, train control or cab signal 

territory where movements over the switch exceed 20 mph. 

This rule prescribes where spring switch protection is required. Rules 236.13 and 236.14 

prescribe how it will operate. 

On all spring switches installed after October 1, 1950, in automatic block signal, train stop, train 

control, and cab signal territory where the speed exceeds 20 mph, signal protection is required in 

the facing and both trailing routes. 

Protection is required only with the current of traffic on track signaled for movement in one 

direction. 

Protection is required for movements against the current of traffic from the reverse main of main 

tracks to a single main track. 

CLASSIFICATION OF DEFECTS

236.12.A1 Signal protection not provided for facing movements through spring switch within 

interlocking limits. 

236.12.A2 Signal protection not provided for trailing movements through spring switch 

within interlocking limits. 

236.12.A3 Signal protection not provided for facing movements over spring switch in track 

signaled for movements in both directions within automatic block signal, train 

stop, train control, or cab signal territory where train movements over switch 

exceed 20 mph. (Applies only to spring switch installed after October 1, 1950.) 

236.12.A4 Signal protection not provided for trailing movements through spring switch in 

automatic block signal, train stop, train control, or cab signal territory where train 

movements over switch exceed 20 mph. (Applies only to spring switch installed 

after October 1, 1950.) 
236-26 

§ 236.13 Spring switch; selection of signal control circuits through circuit controller.

 The control circuits of signals governing facing movements over a main track spring switch 

shall be selected through the contacts of a switch circuit controller, or through the contacts of 

relay repeating the position of such circuit controller, which, when normally closed switch point 

is open 1⁄4-inch or more, will cause such signals to display their most restrictive aspects, except 

that where a separate aspect is displayed for facing movements over the switch in the reverse 

position the signal shall display its most restrictive aspect when the switch points are open 1⁄4-

inch or more from either the normal or reverse position.

Application: 

This rule requires that control circuits (of signals governing facing movements over a main track 

spring switch) be selected through the switch circuit controller or a relay repeating the position 

of such circuit controller. 

This rule applies to interlockings, automatic block signal, and other protective systems. Rules 

236.303 and 236.342 apply to spring switches in interlocking and traffic control systems. 

This rule requires point protection for facing movements over spring switch. Trailing protection 

is not required. 

Control circuits for facing movements must be selected through either switch circuit controller or 

track relay where switch shunting circuit is used. 

This rule applies to spring switch provided with signal protection in nonsignaled territory. It 

does not require such protection be provided, but if protection is provided, it must meet these 

requirements. 

Testing a spring switch shall be made by placing a 1/4-inch gage 6 inches from the end of the 

switch point on either the normal or reverse side and then placing the spring switch throw lever 

in either the full normal or reverse position as appropriate. 

CLASSIFICATION OF DEFECTS

236.13.A1 Control circuits of signal governing facing movements over main track spring 

switch not selected through contacts of switch circuit controller or through 

contacts of relay repeating the position of switch circuit controller. 

236.13.A2 Signal governing facing movements over main-track spring switch does not 

display its most restrictive aspect when normally closed switch point is open 1⁄4-

inch or more. (Does not apply where separate aspect is displayed for facing 

movement over the switch in the reverse position.) 

236.13.A3 Signal governing facing movements over main-track spring switch in both the 

normal and reverse positions does not display its most restrictive aspect when the 

switch points are open 1⁄4-inch or more from either the normal or reverse position. 
236-27 

§ 236.14 Spring switch signal protecting; requirements. 

 (a) The indication of signal governing movements from siding to main track with the current 

of traffic on track signaled for movements in only one direction through a spring switch in 

automatic block signal territory shall be not less restrictive than “Proceed at Restricted Speed” 

when the block, into which movements are governed by the signal, is occupied, and shall be 

“Stop” when the main track is occupied by a train approaching the switch within at least 1,500 

feet in approach of the approach signal located stopping distance from the main track signal 

governing trailing movements over switch, except that the indication may be caused to be less 

restrictive if approach or time locking is used. 

 (b) The indication of signal governing movements against the current of traffic from the 

reverse main of main tracks to a single track, or signal governing movements from a siding to a 

main track signaled for movements in either direction, through a spring switch, in automatic 

block signal territory, shall be not less restrictive than “Proceed at Restricted Speed” when the 

block, into which movements are governed by the signal, is occupied by a preceding train, and 

shall be “Stop” when the block on the single track into which the signal governs is occupied by 

an opposing train. 

 (c) The indication of signal governing movements against the current of traffic from the 

reverse main of main tracks to a single track or signal governing movements from a siding to a 

main track signaled for movements in either direction through a spring switch in automatic block 

signal territory shall be “Stop” when the normal direction main track of the double track or the 

single track signaled for movements in both directions is occupied by a train approaching the 

switch within at least 1,500 feet in approach of the approach signal located stopping distance 

from the main track signal governing trailing movements over switch, except that indication may 

be caused to be less restrictive if approach or time locking is used. 

Application: 

This rule prescribes how spring switch signal protection required by Rule 236.12 shall operate in 

automatic block signal territory (1) when it governs movements with the current of traffic from a 

siding to main track signaled for movements in one direction; (2) when it governs movements 

from a siding to a main track signaled for movements in either direction; and (3) when it governs 

movements from the end of double track territory signaled for movements in one direction with 

the current of traffic to single track territory. It permits the use of approach or time locking. 

This rule applies to automatic block signal territory only. 

Paragraph (a) sets forth the requirements for signals governing movements from siding to main 

track signaled for movements with the current of traffic. 

Paragraph (b) sets forth the requirements for signals governing movements against the current of 

traffic from the reverse main of main tracks to single track or from siding to main track signaled 

for movements in either direction when block into which signal governs is occupied by 

preceding trains or by opposing trains. 

Paragraph (c) sets forth the requirements for signals governing movements against the current of 

traffic from the reverse main of main tracks to single track or from siding to main track signaled 

for movements in either direction when a train is approaching the switch within 1,500 feet in 

approach of the approach signal located stopping distance from the main track signal governing 

trailing movements over the spring switch. 
236-28 

Tests to determine compliance with paragraph (a) should be conducted by placing a shunt in the 

block of the signal governing movements from siding to main track. The signal should then be 

observed to determine whether its aspect is not more favorable than “Proceed at Restricted 

Speed.” 

Tests should then be made by shunting each track circuit on the main track, from at least 1,500 

feet in approach to the approach signal to the main track signal governing trailing movements 

over the switch. The leave siding signal should be observed to determine that its aspect is “Stop” 

when each track circuit is shunted. This test procedure is the same whether the main track signal 

governing trailing movements over the switch is located adjacent to the leave-siding signal or 

located a mile or more in approach of the switch. 

A time release, pushbutton, or key release may be provided that, when operated, causes the main 

track signal to indicate “Stop” or “Stop and Proceed” and will permit the leave siding signal to 

clear after a predetermined time interval. 

Test to determine compliance with paragraph (b) should be conducted by making an operational 

shunt test in approach to and then in the block of the main track signal governing trailing 

movements over the switch into single track and observing the reverse main or leave siding 

signal aspect to determine if it is not more favorable than “Proceed at Restricted Speed” for a 

following movement. Test should then be made by making an operational shunt test on single 

track in the facing direction and observing the reverse main or leave siding signal aspect to 

determine whether it is “Stop” for an opposing movement. 

Tests to determine compliance with paragraph (c) should be conducted by making an operational 

shunt test from at least 1,500 feet in approach to the approach signal to the main track signal 

governing trailing movements over the switch and observing the reverse main or leave siding 

signal aspect to determine that it indicates “Stop” until the switch is passed. 

CLASSIFICATION OF DEFECTS

236.14.A1 Indication of signal governing movements from siding to main track with the 

current of traffic on track signaled for movements in only one direction through 

spring switch in automatic block signal territory, less restrictive than “Proceed at 

Restricted Speed” when the block, into which movements are governed by the 

signal, is occupied. 

236.14.A2 Indication of signal governing movements from siding to main track with the 

current of traffic on track signaled for movements in only one direction through 

spring switch in automatic block signal territory, not “Stop” when main track is 

occupied by a train approaching switch within at least 1,500 feet in approach of 

the approach signal for the main track signal governing trailing movements over 

switch. 

236.14.B1 Indication of signal governing movements against the current of traffic from the 

reverse main of main tracks to single track through spring switch in automatic 

block signal territory, less restrictive than “Proceed at Restricted Speed” when the 
236-29 

block, into which movements are governed by the signal, is occupied by a 

preceding train. 

236.14.B2 Indication of signal governing movements from siding to main track signaled for 

movements in either direction, through spring switch in automatic block signal 

territory, less restrictive than “Proceed at Restricted Speed” when the block, into 

which movements are governed by the signal, is occupied by a preceding train. 

236.14.B3 Indication of signal governing movements against the current of traffic from 

reverse main of main tracks to single track through spring switch in automatic 

block signal territory, not “Stop” when the block on the single track into which 

the signal governs is occupied by an opposing train. 

236.14.B4 Indication of signal governing movements from siding to main track signaled for 

movements in either direction through spring switch in automatic block signal 

territory, not “Stop” when the block on the single track into which the signal 

governs is occupied by an opposing train. 

236.14.C1 Indication of signal governing movements against the current of traffic from the 

reverse main of main tracks to single track through spring switch in automatic 

block signal territory, not “Stop” when the normal direction main track of the 

double track is occupied by a train approaching the switch within at least 1,500 

feet in approach of the approach signal for the main-track signal governing 

trailing movements over switch. 

236.14.C2 Indication of signal governing movements from siding to main track signaled for 

movements in either direction through spring switch in automatic block signal 

territory, not “Stop” when the single track signaled for movements in both 

directions is occupied by a train approaching the switch within at least 1500 feet 

in approach of the approach signal for the main-track signal governing trailing 

movements over the switch. 

236.14.C3 Indication of signal governing movements from siding to main track with the 

current of traffic on track signaled for movements in only one direction through 

spring switch in automatic block signal territory less restrictive than “Proceed at 

Restricted Speed” when the block into which movements are governed by the 

signal is occupied and approach or time locking is ineffective. 

236.14.C4 Indication of signal governing movements from siding to main track, with the 

current of traffic, on track signaled for movements in only one direction through 

spring switch in automatic block signal territory, not “Stop” when main track is 

occupied by a train approaching switch within at least 1,500 feet in approach of 

the approach signal for the main track signal governing trailing movements over 

the switch and approach or time locking is ineffective. 

§ 236.15 Timetable instructions.

 Automatic block, traffic control, train stop, train control, and cab signal territory shall be 

designated in timetable instructions.
236-30 

Application: 

This rule requires automatic block, traffic control, train stop, train control, and cab signal 

territory be designated in timetable instructions. 

The required territorial information may be published either in the timetable or special 

instructions in any manner the carrier chooses which accurately and uniformly identifies the type 

territory. Interlockings are not required to be so designated. 

CLASSIFICATION OF DEFECTS

236.15.A1 Automatic block signal territory not designated in timetable instructions. 

236.15.A2 Traffic control territory not designated in timetable instructions. 

236.15.A3 Automatic train stop territory not designated in timetable instructions. 

236.15.A4 Automatic train control territory not designated in timetable instructions. 

236.15.A5 Automatic cab signal territory not designated in timetable instructions. 

§ 236.16 Electric lock, main track releasing circuit.

 When an electric lock releasing circuit is provided on the main track to permit a train or an 

engine to diverge from the main track without time delay, the circuit shall be of such length to 

permit occupancy of the circuit to be seen by a crewmember stationed at the switch. When the 

releasing circuit extends into the fouling circuit, a train or engine on the siding shall be prevented 

from occupying the releasing circuit by a derail either pipe-connected to switch point or 

equipped with an independently-operated electric lock.

Application: 

This rule sets forth the requirements for main track releasing circuit for electric lock on handoperated switch. 

This rule does not require that a mainline quick release circuit be installed at electrically locked 

switches. However, where such circuits are installed, the rule prohibits the electric lock 

releasing circuit on the main track from being of such length that distance or curvature of track 

will prevent a crewmember standing at the switch from observing a train or car occupying the 

releasing circuit. 

The rule also requires that where the electric lock releasing circuit extends into the fouling 

section of turnout, a train shall be prevented from occupying the fouling section by pipeconnected or independently operated, electrically locked derail at the clearance point. The 

releasing circuit shall be considered as extending into the fouling section if it extends further 

than the heel of the switch points. 

Note: The provisions of § 236.205(d) are applicable to the relay used to provide quick release as 

it is considered a “track circuit relay.” If that relay is in its state of allowing quick release (i.e., 

normally energized relay being de-energized, or normally de-energized relay being energized), it 
236-31 

shall affect the opening of the control circuits for signals governing movements over the switch 

in either direction. 

CLASSIFICATION OF DEFECTS

236.16.A1 Length of electric lock releasing circuit on main track too long to permit 

crewmember standing at the switch to see a train or car occupying the releasing 

circuit. 

236.16.A2 Curvature of track on which electric lock releasing circuit is provided prevents 

crewmember standing at the switch from seeing a train or car occupying the 

releasing circuit. 

236.16.A3 Electric lock releasing circuit on main track extends into fouling circuit where the 

turnout is not equipped with a derail at the clearance point either pipe-connected 

to the switch or independently locked, electrically. 

§ 236.17 Pipe for operating connections; requirements.

 (a) Steel or wrought-iron pipe 1 inch or larger, or members of equal strength, shall be used 

for operating connections for switches, derails, movable-point frogs, facing-point locks, 

rail-locking devices of movable bridge protected by interlocking, and mechanically operated 

signals, except up-and-down rod which may be 3⁄4-inch pipe or solid rod. Pipe shall be fully 

screwed into coupling and both ends of each pipe shall be riveted to pipe plug with 2 rivets.

 (b) Pipeline shall not be out of alignment sufficiently to interfere with proper operation, shall 

be properly compensated for temperature changes, and supported on carriers spaced not more 

than 8 feet apart on tangent and curve of less than 2 and not more than 7 feet apart on curve of 

2 or more. With lever in any position, couplings in pipeline shall not foul carriers.

 

Application: 

This rule prescribes a steel or wrought-iron pipe, 1 inch or larger, for operating connections of 

pipeconnected appliances, with each joint fully screwed into coupling with each end of the pipe 

secured by two rivets. Pipe shall be supported on carriers not more than 8 feet apart on tangent 

and curves of less than 2 degrees and not more than 7 feet apart on curves of more than 2 

degrees. Pipeline shall be properly aligned and compensated and couplings shall not foul 

carriers. Up-and-down rods of mechanically operated signals may be 3⁄4-inch pipe or solid rod. 

The steel or wrought-iron pipe prescribed by this rule is a 1-inch nominal inside diameter pipe, 

or 1.315-inch actual outside diameter pipe. A 3⁄4-inch pipe measures 1.05-inch actual outside 

diameter. 

Pipelines should be operated and carefully observed for bowing when pipe is under compression. 

The pipeline shall be so installed that when a device is obstructed, the pipeline shall be prevented 

from bowing enough to permit latching of lever or full drive of power-operated machine. 

Carriers must be complete and properly assembled and spacing strictly adhered to. Pipeline must 
236-32 

be kept in proper alignment and carrier foundations must be secure and permit no movement 

when pipeline is operated. Bent or damaged pipe is prohibited. 

This rule does not apply to pipeline used as “helper rods” associated with power-operated switch 

machines. 

CLASSIFICATION OF DEFECTS

236.17.A1 Operating connection for switch, derail, movable-point frog, facing-point lock, 

rail-locking device of movable bridge protected by interlocking, or mechanically 

operated signal, not made of steel or wrought-iron pipe 1inch or larger, or 

member of equal strength. (Does not apply to up-and-down rod of mechanically 

operated signal.) 

236.17.A2 Pipe not fully screwed into coupling. 

236.17.A3 Pipe not riveted to pipe plug with two rivets. 

236.17.B1 Pipeline out of alignment sufficiently to interfere with proper operation. 

236.17.B2 Pipeline not properly compensated for temperature changes. 

236.17.B3 Pipeline carriers spaced more than 8 feet apart on tangent or on curve of less than 

2 degrees. 

236.17.B4 Pipeline carriers spaced more than 7 feet apart on curve of 2 degrees or more. 

236.17.B5 Coupling in pipeline fouls carrier. 

§ 236.18 Software management control plan.

 (a) Within 6 months of June 6, 2005, each railroad shall develop and adopt a software 

management control plan for its signal and train control systems. A railroad commencing 

operations after June 6, 2005, shall adopt a software management control plan for its signal and 

train control systems prior to commencing operations. 

 (b) Within 30 months of the completion of the software management control plan, each 

railroad shall have fully implemented such plan. 

 (c) For purposes of this section, “software management control plan” means a plan designed 

to ensure that the proper and intended software version for each specific site and location is 

documented (mapped) and maintained through the life-cycle of the system. The plan must 

further describe how the proper software configuration is to be identified and confirmed in the 

event of replacement, modification, or disarrangement of any part of the system.

Application: 

This rule requires that each railroad develop and adopt a software management control plan for 

existing processor-based signal and train control systems. Each railroad must develop and adopt 

a software management control plan on or before December 6, 2005. Each railroad commencing 
236-33 

operations after June 6, 2005, is required to adopt a software management control plan prior to 

commencing operations. 

Each railroad is then required to have its software management control plan fully implemented 

no later than 30 months after its adoption. The deadline for implementation is June 6, 2008. 

“Software management control plan” means a plan designed to ensure that the proper and 

intended software version for each specific site and location is documented (mapped) and 

maintained through the life-cycle of the system. The plan must further describe how the proper 

software configuration is to be identified and confirmed in the event of replacement, 

modification, or disarrangement of any part of the system. 

The requirements of this section apply to all software of processor-based signal and train control 

equipment in service on or after June 6, 2005, including that which is specifically excluded under 

§ 236.911. 

Section 236.18 does not, however, cover products subject to the provisions contained in Part 236, 

Subpart H, which are required to be developed, installed, implemented, and maintained in strict 

accordance with a configuration management control plan contained in an FRA-approved 

Product Safety Plan (PSP). While the requirements of this section do not apply to configuration 

management required within a PSP, a railroad may combine its software management control 

plan with the configuration management control plan and subject those products to the 

requirements in Subpart H. 

The requirements do not apply to hardware except in limited circumstances, such as when 

upgrades in hardware require new or modified software. Disarrangement of hardware also 

should be considered for those occurrences of natural disasters (e.g., lightning, floods, etc.) or 

accidents (e.g., fires, derailments, automobiles that strike instrument housings, etc.) that destroy 

or damage equipment locations to the extent it requires replacement of processor-based 

equipment. 

A software management control plan is an inventory of software at each equipment location of a 

signal or train control system which includes each wayside location, each highway-rail grade 

crossing warning system that provides safety-critical data to a signal or train control system, 

onboard each equipped locomotive, and each departure test point. The plan must reflect the 

existing software, software changes resulting from modifications, upgrades in software, upgrades 

in hardware that require new or modified software, and changes in operating conditions such as 

removal or addition of switches or signals, respacing, and increased speeds. The plan should be 

updated to reflect each change to previous versions 

of software. FRA inspectors and FRA-certified State inspectors should be able to determine 

from the software management control plan precisely what software is installed at each location. 

A software management control plan will track the version of software that should be and is in 

use in all equipment locations of a signal and train control system. The plan should identify and 

document, for each equipment location, devices that contain software. FRA is not requiring 

railroads to track changes deeper than that at the program memory device (PROM, PROMS, 

EPROMS, EEPROMS, etc.) level. Accordingly, circuit boards with embedded memory and 

programmable memory devices should be identified in the plan. The plan should identify the 

name of the executive or application software, software version number, software revision 
236-34 

number, date of software revision, and a description of the software cyclic redundancy check. In 

addition, the location of each spare PROM and circuit board with embedded memory should be 

identified. The installation of a spare PROM or circuit board with embedded memory and the 

disposition of each shall be recorded in the software management control plan. The software 

management control plan should stipulate that when testing or otherwise, no PROM or circuit 

board with embedded memory may be replaced with another until it has been verified the 

replacement is correct. 

A software management control plan must require the software to be maintained as specified, 

i.e., software shall be maintained strictly as required by design. The plan should require 

revisions (additions, modifications, and deletions) to processor-based equipment be made only 

upon written approval of the railroad=s designated responsible officer or his/her designated 

representative. Each revision of the software shall be supported by documentation which 

includes and originates from a change request initiated by the railroad or the vendor and be 

attached to the revision document. Software revision control shall require documentation that 

describes the reason for making the change and a description of the change, the supporting 

hardware and compatible interfaces. Each software revision shall contain documentation that 

describes the functional description, change summary, and compatibility summary to ensure the 

revision meets the railroad’s requirements. The documentation for each revision shall contain 

instructions for verifying and field testing any change not covered in the railroad’s rules, 

standards, and procedures that govern installation, maintenance, and testing of processor-based 

equipment. Unless otherwise specifically identified in the documentation, each revision shall be 

installed and tested in accordance with the railroad=s rules, standards, and procedures. 

The software management control plan should specify that a safety-critical software upgrade, 

patch, or revision from a supplier, must be installed without undue delay. The plan should 

identify interim steps to be taken to ensure safety of train operations and the motoring public 

until the safety-critical upgrade, patch, or revision has been installed. 

Upon completion of each revision, the software management control plan shall be updated to 

reflect the change, including software revision number, version number, and date and time 

installed, and name of individual performing the installation. A record of the revision 

installation shall be submitted to the responsible railroad official or his/her designated 

representative, to document that the revision has been installed. The results of tests validating 

each revision should be included, and must be recorded and made part of the software 

management control plan record. 

The software management control plan is required to be maintained on file at a designated 

railroad office, or offices, and available for review or replication by FRA inspectors or FRAcertified State inspectors. (See Technical Bulletin S-06-01 and S-07-01) 

CLASSIFICATION OF DEFECTS

236.18.A1 Software management control plan not developed within prescribed timeframe. 

236.18.A2 Software management control plan not adopted within prescribed timeframe. 

236.18.B1 Software management control plan not fully implemented within prescribed 

timeframe. 
236-35 

236.18.B2 Software management control plan process or procedure not complied with. 

236.18.C1 Software management control plan process or procedure incomplete or 

inadequate. 

236.18.C2 Software management control plan equipment inventory incomplete or inadequate 

in process or procedure. 

236.18.C3 Software version or configuration in service that is unauthorized, incorrect, or 

inappropriate. 

236.18.C4 Software management control plan does not include necessary signal or train control 

processor-based equipment. 

236.18.C5 Software version or configuration in service within a signal or train control 

system, subsystem, or component not included, or inaccurate, in the software 

management control plan equipment inventory. 

236.18.C6 Software management control plan does not include processor-based equipment 

of a highway-rail grade crossing warning system, subsystem, or component which 

provides safety-critical data to a signal or train control system. See § 234.275(f). 

236.18.C7 Software version or configuration in service within a highway-rail grade crossing 

warning system, subsystem, or component which provides safety-critical data to a 

signal or train 

control system not included, or inaccurate, in the software management control 

plan equipment inventory. See § 234.275(f). 

236.18.C8 Software management control plan does not include processor-based equipment 

of other similar systems or protective devices. 

236.18.C9 Software version or configuration in service within an other similar system or 

protective device not included, or inaccurate, in the software management control 

plan equipment inventory. 

Roadway Signals and Cab Signals

§ 236.21 Location of roadway signals.

Each roadway signal shall be positioned and aligned so that its aspects can be clearly 

associated with the track it governs.

Application: 

This rule requires that each signal be positioned and aligned so that the aspect it displays is 

clearly associated with the track it governs. 

Inspectors must be alert for installations where it is possible to mistake the aspect of one signal 

for that of another or where the aspect displayed is not clearly associated with the track it is 

intended to govern. 
236-36 

The FRA relies heavily on the inspector’s judgment to determine whether the location and 

alignment of a signal complies with the intent of this rule. 

CLASSIFICATION OF DEFECTS

236.21.A1 Roadway signal not positioned and aligned so that the aspects it displays can be 

clearly associated with the track it governs. 

§ 236.22 Semaphore signal arm; clearance to other objects.

 At least one-half inch clearance shall be provided between semaphore signal arm, and any 

object that may interfere with its operation. 

Application: 

This rule requires one-half inch clearance between a semaphore arm and any object which may 

interfere with its operation. 

Operational test of semaphore signal should be made to insure any object, including light unit, 

clears the arm and spectacle at least one-half inch throughout its arc of travel. 

CLASSIFICATION OF DEFECTS

236.22.A1 Clearance between semaphore arm and object that may interfere with its operation 

is less than one-half inch. 

§ 236.23 Aspects and indications.

 (a) Aspects shall be shown by the position of semaphore blades, color of lights, position of 

lights, flashing of lights, or any combination thereof. They may be qualified by marker plate, 

number plate, letter plate, marker light, shape and color of semaphore blades or any combination 

thereof, subject to the following conditions:

 (1) Night aspects of roadway signals, except qualifying appurtenances, shall be shown by 

lights; day aspects by lights or semaphore arms. A single white light shall not be used.

 (2) Reflector lenses or buttons or other devices which depend for visibility upon reflected 

light from an external source shall not be used hereafter in night aspects, except qualifying 

appurtenances.

 (b) The aspects of cab signals shall be shown by lights or by illuminated letters or numbers.

 (c) Each aspect displayed by a signal shall be identified by a name and shall indicate action 

to be taken. Only one name and indication shall apply to those aspects indicating the same 

action to be taken; the same aspect shall not be used with any other name and indication.

 (d) The fundamental indications of signal aspects shall conform to the following:

 (1) A red light, a series of horizontal lights or a semaphore blade in a horizontal position shall 

be used to indicate stop.

 (2) A yellow light, a lunar light, or a series of lights or a semaphore blade in the upper or 

lower quadrant at an angle of approximately 45 degrees to the vertical, shall be used to indicate 

that speed is to be restricted and stop may be required.

 (3) A green light, a series of vertical lights, or a semaphore blade in a vertical position in the 

upper quadrant or 60 or 90 in the lower quadrant shall be used to indicate proceed at authorized 
236-37 

speed.

 (e) The names, indications, and aspects of roadway and cab signals shall be defined in the 

carrier’s Operating Rule Book or Special Instructions. Modifications shall be filed with the FRA 

within thirty days after such modifications become effective. 

 (f) The absence of a qualifying appurtenance, the failure of a lamp in a light signal, or a false 

restrictive position of an arm of a semaphore signal shall not cause the display of a less 

restrictive aspect than intended.

Application: 

This rule prescribes how aspects shall be shown, that each aspect shall be named and indicate 

action to be taken, and the fundamental indications of the aspects. 

This rule provides that signals may be qualified, and prohibits the use of reflector lenses or 

buttons or other devices depending upon reflected light for visibility in lieu of signal aspects. It 

prescribes that the names, indications, and aspects be defined in the carrier’s operating rule 

books or special instructions on file with the FRA. 

This rule applies to all systems. Each aspect and indication is required to be defined in carrier’s 

rule book or special instructions. 

Use of single white light is prohibited except for indicators of protective devices such as hotbox 

or dragging equipment detectors, and for use as a qualifying appurtenance. 

It is permissible for carriers to qualify red aspect to permit its use to indicate “Proceed at 

Restricted Speed” without requiring stop. (See § 236.204.) Yellow or lunar aspect must be used 

to approach such signals. 

The absence of a semaphore arm on a semaphore signal is an imperfectly displayed signal and 

does not meet these requirements. 

A fixed signal aspect, without lights or which depends for visibility upon a reflected light from 

an external source, is in violation of this part for night train operation. 

This rule prohibits future installation of reflective devices in lieu of signal aspects such as the 

yellow triangle that will permit a higher speed when certain aspects are displayed. 

The failure of a lamp in a light signal, a false restrictive position of a semaphore arm or the 

absence of a qualifying appurtenance shall not cause a signal to display a more favorable aspect 

than intended. (See Technical Bulletin S-99-01)

CLASSIFICATION OF DEFECTS

236.23.A1 Aspects of roadway signal shown by means other than position of semaphore 

blade, color of lights, position of lights, flashing of lights, or combination thereof. 

236.23.A2 Night aspects of roadway signal not shown by lights. 

236.23.A3 Day aspects of roadway signal not shown by lights or semaphore arms. 
236-38 

236.23.A4 Single white light used for aspect of roadway signal. 

236.23.A5 Reflector lenses, buttons, or other devices which depend for visibility upon 

reflected light from an external source used in night aspect of roadway signal. 

236.23.B1 Aspects of cab signals shown by means other than lights, illuminated letters, or 

illuminated numbers. 

236.23.C1 Signal aspect not identified by name. 

236.23.C2 Signal aspect does not indicate action to be taken. 

236.23.C3 More than one name and indication applies to aspects indicating the same action 

to be taken. 

236.23.C4 Same aspect used with more than one name and indication. 

236.23.D1 Aspect other than a red light, a series of horizontal lights or a semaphore blade in 

the horizontal position, used to indicate stop. 

236.23.D2 Aspect other than a yellow light, a lunar light, a series of lights, or a semaphore 

blade in the upper or lower quadrant at an angle of approximately 45 degrees to 

the vertical, used to indicate that speed is to be restricted and stop may be 

required. 

236.23.D3 Aspect other than a green light, a series of vertical lights, or a semaphore blade in 

a vertical position in the upper or 60E or 90E in the lower quadrant, used to 

indicate proceed at authorized speed. 

236.23.E1 Names, indications and aspects of roadway signals and/or cab signals not defined 

in carrier’s block signal and interlocking rules currently in effect. 

236.23.E2 Copy of modification of carrier’s block signal and interlocking rules not filed with 

the Federal Railroad Administration within thirty days after such modification 

became effective. 

236.23.F1 Signal displays a less restrictive aspect than intended when a qualifying 

appurtenance is missing from its normal location on the signal mast. 

236.23.F2 Signal displays a less restrictive aspect than intended when a lamp fails in a light 

signal. 

236.23.F3 Signal displays a less restrictive aspect than intended when arm of semaphore 

signal assumes a false restrictive position. 

§ 236.24 Spacing of roadway signals.

 Each roadway signal shall be located with respect to the next signal or signals in advance 

which govern train movements in the same direction so that the indication of a signal displaying 

a restrictive aspect can be complied with by means of a brake application, other than an 

emergency application, initiated at such signal, either by stopping at the signal where a stop is 
236-39 

required, or by a reduction in speed to the rate prescribed by the next signal in advance where 

reduced speed is required. 

Application: 

This rule requires signals to be adequately spaced to provide proper distances for reducing 

speeds or stopping by use of other than an emergency brake application before reaching the point 

where reduced speed or stopping is required. 

This rule also requires that in automatic cab signal, train control, and train stop territory, these 

braking distances be adequate to compensate for the 8-second delay time that is designed into 

almost all these systems. Section 236.563 states in part, “...and the spacing of signals to meet 

the requirements of 

§ 236.24 shall take into consideration the delay time.” Thus, the proper spacing of signals must 

also include the spacing of code change points so that a train may comply with the indications of 

a cab signal, train stop, or train control system without using an emergency brake application 

before reaching the point where reduced speed or a stop is required. 

Carrier’s braking distance charts shall be used to determine proper spacing. In the event that a 

carrier does not have a braking distance chart, braking tests may be required at suspected 

locations. 

A proceed aspect authorizes maximum authorized speed to next signal without regard of preview 

of next signal: 

│=────--------------Maximum authorized speed to here----------------------─<│

│=───────────────────────────────────────────────────<│

clear clear 

 

A reduced speed aspect requires spacing adequate to slow to prescribed speed before reaching 

next signal: 

Adequate space to slow to prescribed speed without emergency brake application 

│=──────────────────────────────────────────────────<│

approach diverging approach 

 

An aspect requiring stop at next signal, whether operative or inoperative, requires spacing 

adequate enough to stop without emergency brake application before reaching next signal: 

Adequate space to stop without emergency brake application 

│=──────────────────────────────────────────────────<│

approach stop 

These requirements apply to all systems including protective devices such as slide protection, 

high water protection, movable bridges, spring switches, etc. 
236-40 

Where speed is increased, profiles and circuit plans should be reviewed for proper braking 

distances. 

Where yellow or lunar aspect does not provide stopping distance to stop aspect, an advance 

approach or a successive restrictive signal is necessary. 

CLASSIFICATION OF DEFECTS

236.24.A1 Roadway signal not located with respect to the next signal or signals in advance 

which governs train movements in the same direction, so that when it displays a 

restrictive aspect the indication of that aspect can be complied with by means of a 

brake application, other than an emergency application initiated at such signal, by 

stopping at the signal where a stop is required. 

236.24.A2 Roadway signal not located with respect to the next signal in advance governing 

movements in the same direction, so that when it displays a restrictive aspect the 

indication of that aspect can be complied with by means of a brake application, 

other than an emergency application, initiated at such signal, by a reduction in 

speed to the rate prescribed by the next signal in advance. 

§ 236.26 Buffing device, maintenance.

 Buffing device shall be maintained so as not to cause the signal to display a less restrictive 

aspect than intended.

Application: 

This rule requires that buffing device be so maintained that it cannot cause a signal to display a 

less restrictive aspect than intended. 

Operational testing should be conducted in order to observe that oil or air buffers operate 

properly. 

In the event the buffing device causes a signal to display a less restrictive aspect than intended, a 

false proceed report shall be filed with FRA. 

CLASSIFICATION OF DEFECTS

236.26.A1 Buffing device causes signal to display a less restrictive aspect than intended. 

Track Circuits

§ 236.51 Track circuit requirements. 

 Track relay controlling home signals shall be in deenergized position, or device that 

functions as a track relay controlling home signals shall be in its most restrictive state, and the 

track circuit of an automatic train stop, train control, or cab signal system shall be deenergized in 

the rear of the point where any of the following conditions exist: 
236-41 

 (a) When a rail is broken or a rail or switch-frog is removed except when a rail is broken or 

removed in the shunt fouling circuit of a turnout or crossover, provided, however, that shunt 

fouling circuit may not be used in a turnout through which permissible speed is greater than 45 

miles per hour. It shall not be a violation of this requirement if a track circuit is energized: 

 (1) When a break occurs between the end of rail and track circuit connector; within the limits 

of rail joint bond, appliance or other protective device, which provides a bypath for the electric 

current, or

 (2) As result of leakage current or foreign current in the rear of a point where a break occurs.

 (b) When a train, locomotive, or car occupies any part of a track circuit, including fouling 

section of turnout except turnouts of hand-operated main track crossover. It shall not be a 

violation of this requirement where the presence of sand, rust, dirt, grease, or other foreign 

matter prevents effective shunting, except that where such conditions are known to exist 

adequate measures to safeguard train operation must be taken. 

 (c) Where switch shunting circuit is used:

 (1) Switch point is not closed in normal position.

 (2) A switch is not locked where facing-point lock with circuit controller is used.

 (3) An independently-operated fouling-point derail equipped with switch circuit controller is 

not in derailing position. 

Application: 

This rule is the standard by which all track circuits that control home signals or locking circuits 

shall be designed and installed. This rule is not applicable to track circuits that do not affect the 

safety of train operation. 

This rule applies to all types of track circuits that control home signals or locking circuits. It 

does not apply to track circuits that do not affect safety of train operation such as annunciator 

circuits or approach lighting circuits on nonsignaled sidings. 

Automatic train stop, train control, and cab signal system track circuits required to be 

deenergized under this rule include those superimposed on track circuits of the conjunctive 

system. 

Maximum authorized speed is 45 mph through a turnout equipped with shunt fouling circuit. 

Exception should not be taken to series, or parallel-type track circuits, where a small section of 

the turnout is provided with a shunt fouling circuit. 

Track relay shall be deenergized, or the device that functions as a track relay shall be in its most 

restrictive state when a rail is broken or a rail or switch frog is removed; when any part of the 

track circuit or fouling section is occupied by a train, locomotive, or car; and, where switch 

shunting circuit is used, when switch is not in proper position, facing-point lock is not locked, or 

independently operated derail is not in derailing position. 

It is not a violation if the track relay is not deenergized or the device that functions as a track 

relay is not in its most restrictive state when a rail is broken or removed in a shunt fouling circuit, 

or when a break occurs between the end of a rail and track circuit connector, within the limits of 

a rail joint bond appliance, or other protective device; as a result of leakage current or foreign 

current in the rear of a point where a break occurs, or as a result of sand, rust, dirt, grease, or 

other foreign matter preventing shunting. 
236-42 

Where sand, rust, dirt, grease, or other foreign matter is known to prevent, or possibly prevent, 

effective shunting, the carrier is required to take adequate measures to safeguard safety of train 

operation. 

The track relay must be in the deenergized position or the device that functions as a track relay 

must be in its most restrictive state when a rail is removed. 

Non-shunting sections caused by insulated rail joint stagger on short track circuits and in 

connection with crossing frogs are some of the most overlooked variances with this rule. 

Staggered insulated rail joints in excess of 5 feet create the possibility of cars or locomotives 

occupying part of a track circuit undetected. 

CLASSIFICATION OF DEFECTS

236.51.A1 Track relay not in deenergized position or device that functions as track relay not 

in its most restrictive state in the rear of a broken rail. 

236.51.A2 Track circuit of an automatic train stop, train control, or cab signal system not 

deenergized in the rear of a broken rail. 

236.51.A3 Track relay not in deenergized position or device that functions as a track relay 

not in its most restrictive state in the rear of where a rail or switch frog is removed 

from track. 

236.51.A4 Track circuit of an automatic train stop, train control, or cab signal system not 

deenergized in the rear of where a rail or switch frog is removed from track. 

236.51.A5 Shunt fouling circuit used where permissible speed through turnout is greater than 

45 mph. 

236.51.B1 Track relay not in deenergized position or device that functions as a track relay 

not in its most restrictive state in the rear of where a train, locomotive, or car 

occupies any part of the track circuit except fouling section of turnout of handoperated main track crossover. (Fully explain the condition of the rails with 

respect to the presence of sand, rust, dirt, grease, or other foreign matter). 

236.51.B2 Track circuit of automatic train stop, train control, or cab signal not deenergized 

in the rear of where a train, locomotive, or car occupies any part of a track circuit 

except fouling section of turnout of hand-operated main track crossover. (Fully 

explain the condition of the rails with respect to the presence of sand, rust, dirt, 

grease, or other foreign matter.) 

236.51.B3 Adequate measures to safeguard train operation not taken when it is known that a 

condition of sand, rust, dirt, grease, or other foreign matter exists that has 

prevented effective deenergization of a track circuit when occupied by a train, 

locomotive, or car. 

236.51.B4 Adequate measures to safeguard train operation not taken when it is known that a 

condition of sand, rust, dirt, grease, or other foreign matter exists that has 

prevented 
236-43 

effective deenergization of a track circuit of automatic train stop, train control, or 

cab signal system when occupied by a train, locomotive, or car. 

236.51.C1 Track relay not in deenergized position or device that functions as a track relay 

not in its most restrictive state in the rear of where a switch point is not closed in 

normal position, where switch shunting circuit is used. 

236.51.C2 Track circuit of automatic train stop, train control, or cab signal system not 

deenergized in the rear of where a switch point is not closed in normal position, 

where switch shunting circuit is used. 

236.51.C3 Track relay not in deenergized position or device that functions as a track relay 

not in its most restrictive state in the rear of where a switch is not locked, where 

switch is equipped with facing-point lock with switch circuit controller and, 

where switch shunting circuit is used. 

236.51.C4 Track circuit of automatic train stop, train control, or cab signal system not 

deenergized in the rear of where a switch is not locked, where switch is equipped 

with facing-point lock with circuit controller and, where switch shunting circuit is 

used. 

236.51.C5 Track relay not in deenergized position or device that functions as a track relay 

not in its most restrictive state in the rear of where an independently operated 

fouling-point derail equipped with switch circuit controller is not in derailing 

position, where switch shunting circuit is used. 

236.51.C6 Track circuit of automatic train stop, train control, or cab signal system not 

deenergized in the rear of where an independently operated fouling-point derail 

equipped with switch circuit controller is not in derailing position, where switch 

shunting circuit is used. 

§ 236.52 Relayed cut-section.

 Where relayed cut-section is used in territory where non-coded direct-current track circuits 

are in use the energy circuit to the adjoining track shall be open and the track circuit shunted 

when the track relay at such cut-section is in deenergized position.

Application: 

This rule requires that where energy of non-coded direct-current track circuit is supplied through 

contacts of adjoining non-coded track relay, energy circuit shall be opened and track circuit 

shunted when relay is deenergized. 

Apply this rule at relayed cut-section of non-coded direct-current track circuit only, including 

polar, neutral, or biased relays. 

CLASSIFICATION OF DEFECTS

236.52.A1 Where relayed cut-section is used in territory where non-coded direct-current 
236-44 

track circuits are in use, the energy circuit to the adjoining track circuit not open 

when the track relay at the cut-section is in deenergized position. 

236.52.A2 Where relayed cut-section is used in territory where non-coded direct-current 

track circuits are in use, the adjoining track circuit not shunted when the track 

relay at the cut-section is in deenergized position. 

§ 236.53 Track circuit feed at grade crossing. 

 At grade crossing with an electric railroad where foreign current is present, the electric 

energy for non-coded direct current track circuit shall feed away from the crossing.

Application: 

At a crossing-at-grade of a non-electrified railroad using non-coded direct current track circuits 

with an electrified railroad, this rule requires the battery end of direct current track circuit be 

located at the crossing. 

This rule is not applicable unless foreign current is proven to be present. 

CLASSIFICATION OF DEFECTS

236.53.A1 At grade crossing with an electric railroad where foreign current is present, the 

electric energy for non-coded direct current track circuit feeds toward the 

crossing. 

§ 236.54 Minimum length of track circuit.

 When a track circuit shorter than maximum inner wheelbase of any locomotive or car 

operated over such track circuit is used for control of signaling facilities, other means shall be 

used to provide the equivalent of track circuit protection.

Application: 

This rule permits the use of track circuits shorter than the inner wheelbase of any locomotive or 

car, provided other means are used to provide the equivalent of track circuit protection. 

Track circuits shorter than the inner wheelbase of any locomotive or car operating over the track 

are prohibited unless supplemented with other protective devices or circuits that provide 

protection equivalent to a track circuit. 

This rule is applicable to all track circuits that control home signals or electric locking circuits. 

The rule does not apply to track circuits used exclusively for approach lighting circuits on 

sidings or auxiliary tracks, or as annunciator circuits or other non-vital-type track circuits. 

In addition to trap circuits, directional stick circuits, and check-in check-out circuits permitted in 

the past, carriers may now provide devices that detect the presence of locomotives or cars (e.g., 

presence detectors) if such devices are so interconnected with the signaling system that it will 

perform equivalent to a track circuit of proper length. 
236-45 

CLASSIFICATION OF DEFECTS

236.54.A1 Length of track circuit used for controlling signaling facilities that is less than 

maximum inner wheelbase of locomotive or car, not supplemented by special 

circuit or protective device that provides the equivalent of track circuit protection. 

§ 236.55 Dead section; maximum length.

 Where dead section exceeds 35 feet, a special circuit shall be installed. Where shortest outer 

wheelbase of a locomotive operating over such dead section is less than 35 feet, the maximum 

length of the dead section shall not exceed the length of the outer wheelbase of such locomotive 

unless special circuit is used. 

Application: 

This rule prohibits the use of a dead section longer than the shortest outer wheelbase of a 

carrier’s locomotive, but in no case longer than 35 feet, without protecting it with a special 

circuit. 

This rule applies to the outer wheelbase of locomotives only and does not apply to cars. 

Trap circuits are more commonly used to protect dead sections; however, directional stick 

circuits fall into the category of special circuits. 

A presence detector or other such devices satisfy the requirement of this part. 

This rule is not applicable to non-shunting section caused by the stagger of insulated rail joints. 

Apply 

§ 236.51 where stagger of insulated rail joints permits cars to span a live rail of the track circuit. 

CLASSIFICATION OF DEFECTS

236.55.A1 Dead section exceeds 35 feet and special circuit is not installed. 

236.55.A2 Length of dead section exceeds the length of the outer wheelbase of a locomotive 

operating over such dead section and special circuit is not installed. (Applies 

where the length of the outer wheelbase of a locomotive is less than 35 feet.) 

§ 236.56 Shunting sensitivity.

 Each track circuit controlling home signal or approach locking shall be so maintained that 

track relay is in deenergized position, or device that functions as a track relay shall be in its most 

restrictive state if, when track circuit is dry, a shunt of 0.06 ohm resistance is connected across 

the track rails of the circuit, including fouling sections of turnouts.

Application: 

This rule requires that a track circuit controlling signal aspects or electric locking shall be 

maintained so that when a shunt of 0.06 ohm resistance is connected across the rails of the track 
236-46 

circuit at any location in the circuit, including fouling sections of turnouts, the track relay shall 

assume the deenergized position or if an electronic device is used in lieu of a track relay, such 

electronic device shall assume its most restrictive state. 

This rule applies to any type track circuit of which the rails form a part of the circuit and which is 

used for controlling signal aspects or electric locking. It does not apply to approach lighting 

circuits on nonsignaled track, annunciator circuits, etc. 

The most difficult time to shunt a track circuit is when the ballast is dry or frozen. 

Car frame type track circuit must comply with this section. 

Each turnout has three locations within the fouling section that should be tested. Those locations 

are both sides of the turnout blocking joints and at the clearance end of the circuit. 

“Most restrictive state” is defined in § 236.813a as the mode of an electronic device that is 

equivalent to a track relay in its deenergized position. Regardless of the type of track circuit, this 

rule requires that signals governing movements over the track circuit must display their most 

restrictive aspects when the track circuit, including fouling sections of turnouts within the circuit, 

is shunted with a shunt of 0.06 ohms resistance. 

CLASSIFICATION OF DEFECTS

236.56.A1 Track relay not in deenergized position or device that functions as a track relay 

not in its most restrictive state with a shunt of 0.06 ohm resistance connected 

across rails of the track circuit, when track circuit is dry. 

§ 236.57 Shunt and fouling wires.

(a) Except as provided in paragraph (b) of this section, shunt wires and fouling wires 

hereafter installed or replaced shall consist of at least two discrete conductors, and each shall be 

of sufficient conductivity and maintained in such condition that the track relay will be in 

deenergized position, or device that functions as a track relay will be in its most restrictive state, 

when the circuit is shunted. 

(b) This rule does not apply to shunt wires where track or control circuit is opened by the 

switch circuit controller. 

Application: 

Shunt wires and fouling wires are each required to be of sufficient conductivity and maintained 

in such condition that the track relay will be deenergized, or device that functions as a track relay 

in its most restrictive state, when the track circuit is shunted. Two completely separate 

conductors are required, except where switch circuit controller is used to both open control 

circuits and shunt the track circuit. 

The reasoning for the two separate conductors is that these wires do not meet the closed circuit 

principle in that one or both may be missing, broken, or otherwise ineffective, yet no indication 

of that condition would occur within the signal system. An unsafe situation could therefore be 

undetected thus two separate conductors are required to help assure their proper and intended 

conductivity. 
236-47 

This rule prohibits the installation of a single duplex wire with single plug as fouling or shunt 

wires. The single plug constitutes a single conductor. Existing installations having single duplex 

wires with single plug for shunt or fouling wires may be continued in use until such time as they 

require repair or replacement. The use of two duplex wires with single plug is acceptable. 

A conductor consisting of many small strands, such as that with the trade name “Bondstrand,” 

can be only considered as a single conductor. 

Two fouling wires are required at the heel of the reverse switch point, at the toe and heel of the 

switch frog, and between the outer rails of the main track and turnout. 

Shunt wires to switch circuit controller shall consist of two separate conductors connected to 

each rail and extending to the terminals of switch circuit controller. 

This rule applies to not only shunt wires of switches or derails located on the signaled track, but 

also to those used at inside switches or fouling point derails located on a nonsignaled track 

leading to a signaled track where the railroad elects to install a switch circuit controller equipped 

with switch shunting circuit to detect the position of the inside switch or fouling point derail (see 

application language for § 236.60). Should such an inside switch or fouling point derail be found 

equipped with only a switch shunting circuit, and one where the shunt wires do not consist of 

two separate conductors, a defect should be cited for noncompliance with this section. 

This rule is not applicable to rail joint bonds in fouling section. 

Note: The points of connection to the main or signaled track rail of the two separate conductors 

of fouling wires, or of shunt wires if strapped together in the switch circuit controller, must not 

be “excessively” spaced apart from one another (e.g., greater than one foot apart). This 

condition may result in a loss of broken rail protection, necessitated by § 236.51, that is 

equivalent to the length of the spacing between the points of connection of the wires to the rail. 

 

CLASSIFICATION OF DEFECTS

236.57.A1 Shunt or fouling wires do not consist of at least two discrete conductors. (Does 

not apply to shunt wires to switch circuit controller through which signal control 

circuits are controlled and track circuits are shunted, or where track circuit is 

opened and relay side of track circuit is shunted.) 

236.57.A2 Shunt wires not of sufficient conductivity so that track relay is in deenergized 

position or device that functions as track relay is in its most restrictive state when 

circuit is shunted. 

236.57.A3 Shunt wires not maintained in such condition that track relay is in deenergized 

position or device that functions as track relay is in its most restrictive state when 

circuit is shunted. 

236.57.A4 Fouling wires not of sufficient conductivity so that track relay is in deenergized 

position or device that functions as track relay is in its most restrictive state when 

circuit is shunted. 
236-48 

236.57.A5 Fouling wires not maintained in such condition that track relay is in deenergized 

position or device that functions as track relay is in its most restrictive state when 

circuit is shunted. 

§ 236.58 Turnout, fouling section.

 Rail joints within the fouling section shall be bonded, and fouling section shall extend at least 

to a point where sufficient track centers and allowance for maximum car overhang and width 

will prevent interference with train, locomotive, or car movement on the adjacent track.

Application: 

This rule requires that each rail joint within all fouling sections be bonded; however, it does not 

require double bonding of those rail joints. 

This rule requires that the fouling section of each turnout shall extend at least to a point on the 

turnout where a standing standard-sized car or locomotive will clear a movement of other 

standard-sized cars or locomotives on the main track, under all circumstances, including with 

consideration of such as overhang of cars, track curvature, etc. This minimum clearance is not 

applicable to crossovers between tracks as they are protected by a combination of switch position 

and track circuit detection. 

An acceptable method of determining the absolute least clearance point consists of taking a 

measurement 11 feet (to account for car overhang) ahead of the effective joint at the end of the 

fouling section (toward the switch points) and the measurement from the field side of that point 

on the near rail of the fouling section to the field side of the near main track rail must not be less 

than 6 feet 6 inches (to account for car width). Curved track areas may necessitate a minimal 

additional length be added to the 6-foot-6-inch measurement to allow for the near front corner of 

a car being skewed toward the adjacent track account being in a curve. 

Note: See the fouling section clearance point diagram included at the end of this manual for 

detailed explanation of measurements. 

CLASSIFICATION OF DEFECTS

236.58.A1 Rail joint in shunt fouling section not bonded. 

236.58.A2 Fouling section of turnout does not extend to clearance point. 

§ 236.59 Insulated rail joints.

 Insulated rail joints shall be maintained in condition to prevent sufficient track circuit current 

from flowing between the rails separated by the insulation to cause a failure of any track circuit 

involved.

Application: 

Insulated rail joints are required to be maintained in such condition as to prevent energy from 

flowing between adjoining track circuits. 

This rule applies to all insulated rail joints in all systems. 
236-49 

An insulated rail joint is considered defective when intended insulation is clearly seen to be in 

bad condition or missing, or tests prove insulation is worn, deteriorated, or otherwise bypassed 

so as to conduct sufficient current between adjoining track circuits to cause track circuit failure. 

Where the intended insulation is visibly seen to be in bad condition or missing, testing of the 

insulated joint should be conducted in order to determine if the joint is currently failing so as to 

necessitate immediate repair or replacement. 

The breakdown of insulation in a single insulated rail joint is considered a failure of a track 

circuit even though the insulated rail joint on the other rail is in good condition. 

CLASSIFICATION OF DEFECTS

236.59.A1 Insulated rail joint not maintained in condition to prevent flow of sufficient track 

circuit current between rails separated by the insulation to cause failure of the 

track circuit. 

236.59.A2 Insulated rail joint not maintained in such a condition that the track circuit 

through the switch circuit controller can be opened when switch point open. 

236.59.A3 Insulation in insulated rail joint in bad condition. 

§ 236.60 Switch shunting circuit, use restricted.

 Switch shunting circuit shall not be hereafter installed, except where track or control circuit 

is opened by the circuit controller.

Application: 

This rule applies to all systems, including signal arrangements such as tunnel protection, slide 

detector, or high water detector. 

This rule applies to not only switches or derails located on the signaled track, but also to those 

inside switches or fouling point derails located on a nonsignaled track leading to a signaled track 

where the railroad elects to install a switch circuit controller to detect the position of the inside 

switch or fouling point derail. 

In the latter case, as is stated in the Himmel Letter of 1985, “The FRA will consider granting 

relief from the requirements of this section at such installations upon an adequate showing by 

individual carriers.” Should such an inside switch or fouling point derail be found equipped only 

with a switch shunting circuit, a defect should be cited for noncompliance with this section and 

the railroad advised to either correct the deficiency, or timely submit a request for relief. 

This rule prohibits the use of a switch shunting circuit as the only method of protection. 

The rule permits the use of a circuit to shunt the track circuit only if the circuit controller also 

opens the track circuit or a signal control circuit. 

This rule permits the continued use of existing installations of switch shunting circuits. 
236-50 

This rule applies to all new switch locations in revenue service. FRA has defined a new switch 

as: 

 An additional switch installed in a system existing on February 27, 1984. 

 All switches of each system installed after February 26, 1984. 

 A switch installed as the result of the shortening or lengthening of a siding or other 

auxiliary track except when such switch is moved for routine track maintenance 

(including rail relay) or the angle of the switch frog is changed as the result of a change in 

carrier track standards. 

CLASSIFICATION OF DEFECTS

236.60.A1 Switch shunting circuit installed where track circuit or control circuit not opened 

by switch circuit controller. (Does not apply to installations made before 

February 27, 1984.) 

Wires and Cable

§ 236.71 Signal wires on pole line and aerial cable.

 Signal wire on pole line shall be securely tied in on insulator properly fastened to crossarm or 

bracket supported by pole or other support. Signal wire shall not interfere with, or be interfered 

by, other wires on the pole line. Aerial cable shall be supported by messenger.

Application: 

Signal wires carried on pole lines are required to be securely tied in on insulators properly 

fastened to a crossarm or bracket which is supported by a pole or other support. Cable used 

aerially is required to be supported by messenger. 

The intent of this rule is that all signal wires, including AC power supply carried on pole line, are 

required to be tied in on insulators that are securely fastened to a crossarm or bracket attached to 

a pole or other fixture, such that each signal wire is maintained clear of all other wires. Further, 

aerial cable is to be supported by a messenger wire such that the weight of the cable is not being 

supported by the cable itself. 

Particular attention should be given to vertical runs of cable. These are frequently found tied off 

at the top of the run at which point the entire weight of the cable is self-supported. The cable is 

required to be supported throughout by messenger. 

CLASSIFICATION OF DEFECTS

236.71.A1 Signal wire carried on pole line not securely tied in on insulator. 

236.71.A2 Signal wire not secured because of broken, burnt, or missing crossarm. 

236.71.A3 Signal wire not secured because of broken, burnt, or missing pole. 
236-51 

236.71.A4 Signal wire interferes with or is interfered by another wire. 

236.71.A5 Cable used aerially not supported by messenger. 

§ 236.73 Open-wire transmission line; clearance to other circuits.

 Open-wire transmission line operating at voltage of 750 volts or more shall be placed not less 

than 4 feet above the nearest cross arm carrying signal or communication circuits.

Application: 

This rule requires that open-wire transmission lines of 750 volts or more be placed at least 4 feet 

above the nearest crossarm carrying signal or communication wires. This rule applies where 

power of 750 volts or more is transmitted by open-wire line. 

CLASSIFICATION OF DEFECTS

236.73.A1 Open-wire transmission line operating at voltage of 750 volts or more, less than 4 

feet above nearest crossarm carrying signal or communication circuits. 

§ 236.74 Protection of insulated wire; splice in underground wire.

 Insulated wire shall be protected from mechanical injury. The insulation shall not be 

punctured for test purposes. Splice in underground wire shall have insulation resistance at least 

equal to the wire spliced.

Application: 

This rule requires that insulated wire be protected from mechanical injury. It prohibits 

puncturing insulation for test purposes, and requires that a splice in an underground wire has 

insulation resistance at least equal to that of the wire spliced. 

Insulated wire shall be placed in wire runs, strung on pole line, supported by messenger wire, or 

buried in a manner that it cannot be damaged by the operation of apparatus, vehicles, tools, 

workmen, or by closing doors or other enclosure covers or lids. 

No insulated wire or conductor, whether in housing or outside, should be punctured for test 

proposes. 

This rule does not permit the extended use of temporary installation of cable or wires on top of 

the ground. Such necessary temporary use shall be made permanent without undue delay or, as 

quickly as possible. 

CLASSIFICATION OF DEFECTS

236.74.A1 Insulated wire not protected from mechanical injury. 

236.74.A2 Insulation of insulated wire punctured for test purposes. 
236-52 

236.74.A3 Splice in underground wire does not have insulation resistance value at least equal 

to that of the wire spliced. 

§ 236.76 Tagging of wires and interference of wires or tags with signal apparatus.

 Each wire shall be tagged or otherwise so marked that it can be identified at each terminal. 

Tags and other marks of identification shall be made of insulating material and so arranged that 

tags and wires do not interfere with moving parts of apparatus.

Application: 

Each wire is required to be tagged or otherwise marked so it can be identified at each terminal. 

Nomenclature shall correspond to that of the circuit plan. Tags, or other marks of identification, 

are required to be made of insulating material. Wires and tags are prohibited from interfering 

with moving parts of signal apparatus. 

This rule applies to each wire at each terminal in all housings, including switch circuit 

controllers, switch machines, and terminal or junction boxes. 

Shunt wires inside switch circuit controllers are not required to be tagged as long as the carrier’s 

nomenclature is uniform and corresponds to its circuit plans. 

Signal wiring shall be tagged or otherwise marked at a terminal. A terminal is any point the wire 

terminates from its point of origin to and including the point of final termination. The wire may 

be tagged or marked in any manner so that it can be identified. 

Breaks in a relay or other breaks that are identified on the circuit plan by the terminal post 

number meet the requirements of this rule. However, the circuit plan must be available in the 

signal case in such instances. 

If a carrier identified their wires in this manner, it would require every signal and cut section to 

have a circuit plan. If they do not, and the wires cannot be identified, the installation does not 

comply with this section. 

All tag or wire identification should correspond with the circuit plan. All tags and identification 

should be of insulating material. Wires and tags shall not interfere with the moving parts or 

apparatus. This includes the contact members of relays, switch machines, interlocking machines, 

semaphore signal mechanism and other moving apparatus, etc. 

If it is necessary to pull the wire in order to identify the circuit it carries, the carrier is in 

noncompliance with this section. 

CLASSIFICATION OF DEFECTS

236.76.A1 Wire not tagged or otherwise marked so it can be identified at terminal. 

236.76.A2 Nomenclature of tag or wire identification does not correspond to that of circuit 

plan. 
236-53 

236.76.A3 Tag or other mark of identification in instrument case or apparatus housing not 

made of insulating material. 

236.76.A4 Tag interferes with moving parts of apparatus. 

236.76.A5 Wire interferes with operating part of mechanism. 

Inspections and Tests; All Systems

§ 236.101 Purpose of inspections and tests; removal from service of relay or device failing 

to meet test requirements. 

 The following inspections and tests shall be made in accordance with specifications of the 

carrier, subject to approval of the FRA, to determine if the apparatus and/or equipment is 

maintained in condition to perform its intended function. Electronic device, relay, or other 

electromagnetic device which fails to meet the requirements of specified tests shall be removed 

from service, and shall not be restored to service until its operating characteristics are in 

accordance with the limits within which such device or relay is designed to operate.

Application: 

This rule prescribes that certain inspections and tests of vital importance be made. The 

inspections and tests must be performed in accordance with carrier specifications, which are 

subject to FRA approval. Electronic device, relay or other electromagnetic device that fails to 

meet the requirements of specified tests, must be removed from service and not restored to 

service until its operating characteristics are within the limits prescribed by the manufacturer. 

The rule is applicable to all systems. 

The purpose of inspections and tests are to determine if operating characteristics of relays, 

electronic apparatus, and electromagnetic devices are within specified values, and that apparatus 

and equipment are being maintained in a condition to assure safety of train operation. 

CLASSIFICATION OF DEFECTS

236.101.A1 Relay which failed to meet requirements of specified tests not removed from 

service. 

236.101.A2 Relay which failed to meet requirements of specified tests restored to service with 

operating characteristics not in accordance with the limits within which the relay 

is designed to operate. 

236.101.A3 Relay with broken glass, high resistance or burnt contacts, burnt ribbons, broken 

or bent contacts, improperly installed ribbons, excessive moisture or other foreign 

matter inside it’s housing, not replaced or removed from service. 

236.101.A4 Electromagnetic device other than relay, which failed to meet requirements of 

specified tests, not removed from service. 

236.101.A5 Electromagnetic device other than relay, which failed to meet requirements of 
236-54 

specified tests, restored to service with operating characteristics not in accordance 

with the limits within which the electromagnetic device is designed to operate. 

236.101.A6 Electronic device which failed to meet requirements of specified tests not 

removed from service. 

236.101.A7 Electronic device which failed to meet requirements of specified test restored to 

service with operating characteristics not in accordance with the limits within 

which the electronic device is designed to operate. 

§ 236.102 Semaphore or searchlight signal mechanism.

 (a) Semaphore signal mechanism shall be inspected at least once every 6 months, and tests of 

the operating characteristics of all parts shall be made at least once every 2 years. 

 (b) Searchlight signal mechanism shall be inspected, and the mechanical movement shall be 

observed while operating the mechanism to all positions, at least once every 6 months. Tests of 

the operating characteristics shall be made at least once every 2 years. 

Application: 

This rule requires a visual inspection of semaphore and searchlight signal mechanisms at least 

once every 6 months. Tests of the operating characteristics of these mechanisms are required to 

be made every 

2 years. 

This rule applies to all semaphore and searchlight type signal mechanisms. Record of the 6-

month inspections is not required. This rule requires the observation of the searchlight 

mechanism while it is operated in all positions during the 6-month inspection. 

Tests of operating characteristics include pickup, release, and working values. They may be 

recorded in either voltage or current values, and a record of these tests is required. 

CLASSIFICATION OF DEFECTS

236.102.A1 Semaphore signal mechanism not inspected at least once every 6 months. 

236.102.A2 Test of semaphore signal mechanism operating characteristics not made at least 

once every 2 years. 

236.102.B1 Searchlight signal mechanism not inspected, with the mechanical movement to all 

positions of searchlight mechanism being observed, at least once every 6 months. 

236.102.B2 Test of searchlight signal mechanism operating characteristics not made at least 

once every 2 years. 

§ 236.103 Switch circuit controller or point detector.

 Switch circuit controller, circuit controller, or point detector operated by hand-operated 

switch or by power-operated or mechanically-operated switch-and-lock movement shall be 

inspected and tested at least once every 3 months.
236-55 

Application: 

Switch circuit controllers and point detectors are required to be inspected and tested at least once 

every 3 months. 

Applies to all switch circuit controllers and point detectors in all systems required by 49 CFR §§ 

236.6, 236.13, 236.51, 236.57, 236.202, 236.203, 236.334, and 236.342. 

Inspection should determine general condition, such as extent of wear of bushings, bearings, and 

connections, secureness of fastenings, condition of contacts and shunt wires, wiring, gaskets, 

etc., in compliance with these rules. 

Test should be made with the obstruction gage placed between the stock rail and the switch 

point, 6 inches from the end of the switch point, to determine proper adjustment and operation. 

This rule is not applicable to a switch that is removed from revenue service and is effectively 

spiked, clamped, or blocked in proper position. Inspectors should be aware of the carrier’s 

procedure for the removal of the switches from service. 

CLASSIFICATION OF DEFECTS

236.103.A1 Switch circuit controller not inspected at least once every 3 months. 

236.103.A2 Tests of switch circuit controller not made at least once every 3 months. 

236.103.A3 Point detector not inspected at least once every 3 months. 

236.103.A4 Tests of point detector not made at least once every 3 months. 

§ 236.104 Shunt fouling circuit.

 Shunt fouling circuit shall be inspected and tested at least once every 3 months.

Application: 

Each shunt fouling circuit is required to be inspected and tested at least once every 3 months. 

This rule applies to all shunt fouling circuits in all systems. 

Inspections should determine if bonds and fouling wires are applied and maintained in 

compliance with 49 CFR §§ 236.51, 236.56, 236.57, and 236.58, at the proper places, and are 

intact and in good condition. If visual inspection of fouling wires is unavailable due to being 

hidden from view (e.g., their being covered by ballast), noncompliance with this rule should be 

cited. 

Test should be made at the defined limit of the fouling circuit (i.e., at the far insulated joints) and 

on both sides of the insulated rail joints located between the switch points and the frog, by 

connecting a 0.06 ohm shunt across the rails and determining if the associated track relay is in a 

deenergized position, or the device that functions as a track relay is in its most restrictive 

condition. If a fouling circuit is found without a clearly defined limit (no limiting insulated 

joints), it must be found to be effective at least to the clearance point. 
236-56 

A switch removed from revenue service does not eliminate the requirements of this rule. 

CLASSIFICATION OF DEFECTS

236.104.A1 Shunt fouling circuit not inspected at least once every 3 months. 

236.104.A2 Tests of shunt fouling circuit not made at least once every 3 months. 

§ 236.105 Electric lock.

 Electric lock, except forced-drop type, shall be tested at least once every 2 years.

Application: 

This rule requires that electric locks be tested once every 2 years. It excludes forced-drop type 

electric locks. This rule applies to all systems and interlocking machines. 

Locks failing to meet test requirements must be replaced. Electric locks of the non-forced-drop 

type may be removed from service, repaired, and replaced in service. 

Tests of operating characteristics include pickup, release, and working values. They may be 

recorded in either voltage or current values. 

CLASSIFICATION OF DEFECTS

236.105.A1 Test of electric lock not made at least once every 2 years. (Does not apply to 

electric locks of forced-drop type.) 

§ 236.106 Relays.

 Each relay, the functioning of which affects the safety of train operations, shall be tested at 

least once every 4 years except: 

 (a) Alternating current centrifugal type relay shall be tested at least once every 12 months; 

 (b) Alternating current vane type relay and direct current polar type relay shall be tested at 

least once every 2 years; and 

 (c) Relay with soft iron magnetic structure shall be tested at least once every 2 years.

Application: 

This rule requires that each relay used in vital circuits of wayside equipment be tested at intervals 

prescribed for its type of design. This rule applies to relays used in vital circuits of wayside 

equipment in all systems. 

Each relay is required to be tested at least once every 4 years except: 

1. Centrifugal relays shall be tested at least once every 12 months. 

2. Vane relays and DC polar relays shall be tested at least once every 2 years. 

3. Relays with soft iron magnetic structure, which tends to become permanently 
236-57 

magnetized, shall be tested at least once every 2 years. 

This rule is applicable only to relays in service. A new relay placed in service shall be tested at 

intervals prescribed for its type of design. A shopped relay, after being tested or repaired in the 

shop, is not considered in service until it is installed within a signal system. 

A visual inspection of each relay is intended to be an integral part of the testing. A relay that has 

broken glass, high-resistance contacts, burnt contacts, burnt ribbons, broken or bent contacts, 

improperly installed ribbons, or evidence of moisture or other foreign matter inside its housing, 

is not properly maintained and is prohibited. 

Tests of operating characteristics include pickup, release, and working values. They may be 

recorded in either voltage or current values. 

CLASSIFICATION OF DEFECTS

236.106.A1 Tests of relay in service not made at least once every 4 years. 

236.106.A2 Tests of centrifugal relay in service not made at least once every 12 months. 

236.106.B1 Tests of AC vane relay not made at least once every 2 years. 

236.106.B2 Tests of DC polar relay not made at least once every 2 years. 

236.106.C1 Tests of relay with soft iron magnetic structure not made at least once every 2 

years. 

§ 236.107 Ground tests.

 (a) Except as provided in paragraph (b) of this section, a test for grounds on each energy bus 

furnishing power to circuits, the functioning of which affects the safety of train operation, shall 

be made when such energy bus is placed in service, and shall be made at least once every 3 

months thereafter. 

 (b) The provisions of this rule shall not apply to track circuit wires, common return wires of 

grounded common single-break circuits, or alternating current power distribution circuits 

grounded in the interest of safety.

Application: 

This rule requires that a test for grounds on vital circuitry be made when placed in service and at 

least once every 3 months thereafter. 

This test shall be made at energy buses supplying power to signal control circuits. Use of an 

appropriate external battery source is an acceptable means of testing. This test is not required to 

be made on track circuit wires, AC distribution circuits grounded in the interest of safety, or 

common return wires of grounded common single break circuits. 

This test shall be made by measuring the voltage potential between each energy bus and the 

ground. If a voltage potential is detected between the energy bus and the ground, a current 

reading shall be taken to determine whether the ground is in excess of that permitted by § 236.2. 
236-58 

In no case shall a current reading be taken when a train is closely approaching or passing, or a 

meter connected between an energy bus and the ground be left unattended. 

This ground test should also be applied to each output circuit of those electronic devices installed 

to provide one or more individual isolated power supplies from a single common storage battery 

or power supply. (See Technical Bulletin S-99-03)

CLASSIFICATION OF DEFECTS

236.107.A1 Ground test on energy bus which furnishes power to circuits, the functioning of 

which affects the safety of train operation, not made when energy bus is placed in 

service. 

236.107.A2 Ground test on energy bus which furnishes power to circuits, the functioning of 

which affects the safety of train operation, not made at least once every 3 months. 

§ 236.108 Insulation resistance tests, wires in trunking and cables.

 (a) Insulation resistance of wires and cables, except wires connected directly to track rails, 

shall be tested when wires, cables, and insulation are dry. Insulation resistance tests shall be 

made between all conductors and ground, and between conductors in each multiple conductor 

cable, and between conductors in trunking, when wires or cables are installed and at least once 

every 10 years thereafter.

 (b) When insulation resistance of wire or cable is found to be less than 500,000 ohms, prompt 

action shall be taken to repair or replace the defective wire or cable and until such defective wire 

or cable is replaced, insulation resistance test shall be made annually.

(c) In no case shall a circuit be permitted to function on a conductor having an insulation 

resistance to ground or between conductors of less than 200,000 ohms during the period required 

for repair or replacement.

Application: 

This rule requires tests of insulation resistance of wires in trunking and cable be made when 

installed, and at least once every 10 years thereafter. Conductors found having insulation 

resistance of less than 500,000 ohms shall be tested annually. In no case shall a conductor with 

insulation resistance found of less than 200,000 ohms be left in service. 

Tests must be made when wires, cables, and insulation are dry. However, wet conditions do not, 

under any circumstances, provide relief from § 236.2. 

Insulation resistance tests of each wire within trunking or within a cable must be tested to 

ground, and tested against all other wires within the trunking or cable. 

Single-conductor wire buried underground shall be tested to ground, but is not required to be 

tested against all other wires in the cable run. 

This rule applies to conductors and cables used for signal power. 

Track wires, line wires, and case wiring are excluded from the requirements of this rule. 
236-59 

Where a conductor is found with insulation resistance of less than 500,000 ohms, prompt action 

is required for repair or replacement of the defective wire or cable. Until the defective wire or 

cable is repaired or replaced, insulation resistance tests must be made annually. The reason for 

this provision is to allow lead time for the acquisition of new cable or the scheduling of 

manpower. However, if material and manpower are available to affect repairs or replacement, 

corrective action shall be taken immediately. 

Where a conductor is found with insulation resistance of less than 200,000 ohms, it shall be 

immediately either repaired or removed from service. 

CLASSIFICATION OF DEFECTS

236.108.A1 Test of insulation resistance not made when wires or cables are installed. 

236.108.A2 Test of insulation resistance not made at least once every ten years. 

236.108.B1 Prompt action not taken to repair or replace conductor when its insulation 

resistance is found below 500,000 ohms. 

236.108.B2 Test of insulation resistance not made at least annually until defective wire or 

cable is repaired or replaced when its insulation resistance is found below 500,000 

ohms. 

236.108.C3 Circuit permitted to function on a conductor having insulation resistance found of 

less than 200,000 ohms. 

§ 236.109 Time releases, timing relays, and timing devices. 

 Time releases, timing relays, and timing devices shall be tested at least once every 12 

months. The timing shall be maintained at not less than 90 percent of the predetermined time 

interval, which shall be shown on the plans or marked on the time release, timing relay, or timing 

device.

Application: 

This test requires that time releases, timing relays, and timing devices be tested once every 12 

months, and that timing be maintained at not less than 90 percent of the predetermined time 

interval, which shall be shown on the plans or marked on the time release, time relay, or timing 

device. This rule applies to all systems. 

Tests should not be conducted while rail traffic is approaching or within any route involved in 

the test. 

This test is required to determine the length of time that a time release, timing relay, or timing 

device must run before the associated locking is released. 

Tests shall be conducted by starting the time release, timing relay, or timing device and checking 

the length of time from the instant the device is started, or from the opening of the check contact 

(if used), until the release of the lever lock or energization of electric stick locking relay. 
236-60 

Releasing time must not be less than 90 percent of that shown. It may be any amount of time 

over the predetermined time. Predetermined time interval must be shown on plans or marked on 

the time release, time relay, or timing device. 

CLASSIFICATION OF DEFECTS

236.109.A1 Time release not tested at least once every 12 months. 

236.109.A2 Timing relay not tested at least once every 12 months. 

236.109.A3 Timing device not tested at least once every 12 months. 

236.109.A4 Timing of time release less than 90 percent of predetermined time interval. 

236.109.A5 Timing of timing relay less than 90 percent of predetermined time interval. 

236.109.A6 Timing of timing device less than 90 percent of predetermined time interval. 

236.109.A7 Predetermined time interval not shown on plans or marked on time release, timing 

relay, or timing device. 

§ 236.110 Results of tests. 

 (a) Results of tests made in compliance with §§ 236.102 to 236.109, inclusive; 236.376 to 

236.387, inclusive; 236.576; 236.577; 236.586 to 236.589, inclusive; and 236.917(a) must be 

recorded on preprinted forms provided by the railroad or by electronic means, subject to 

approval by the FRA Associate Administrator for Safety. These records must show the name of 

the railroad, place and date, equipment tested, results of tests, repairs, replacements, adjustments 

made, and condition in which the apparatus was left. Each record must be: 

 (1) Signed by the employee making the test, or electronically coded or identified by number 

of the automated test equipment (where applicable); 

 (2) Unless otherwise noted, filed in the office of a supervisory official having jurisdiction; 

and 

 (3) Available for inspection and replication by FRA and FRA-certified State inspectors. 

 (b) Results of tests made in compliance with § 236.587 must be retained for 92 days. 

 (c) Results of inspections and tests made in compliance with § 236.917(a) must be retained as 

follows: 

 (1) Results of inspections and tests that pertain to installation or modification must be 

retained for the life-cycle of the equipment tested and may be kept in any office designated by 

the railroad; and 

 (2) Results of periodic inspections and tests required for maintenance or repair of the 

equipment tested must be retained until the next record is filed but in no case less than 1 year. 

 (d) Results of all other tests listed in this section must be retained until the next record is filed 

but in no case less than 1 year. 

 (e) Electronic or automated tracking systems used to meet the requirements contained in 

paragraph (a) of this section must be capable of being reviewed and monitored by FRA at any 

time to ensure the integrity of the system. FRA’s Associate Administrator for Safety may 

prohibit or revoke a railroad’s authority to utilize an electronic or automated tracking system in 

lieu of preprinted forms if FRA finds that the electronic or automated tracking system is not 
236-61 

properly secured, is inaccessible to FRA, FRA-certified State inspectors, or railroad employees 

requiring access to discharge their assigned duties, or fails to adequately track and monitor the 

equipment. The Associate Administrator for Safety will provide the affected railroad with a 

written statement of the basis for his or her decision prohibiting or revoking the railroad from 

utilizing an electronic or automated tracking system.

Application: 

This rule requires that the results of tests be recorded and filed in the office of the responsible 

division officer. It specifies those results to be recorded, prescribes the general format to be 

used, and requires that the recording be signed by the employee making the test, or electronically 

coded or identified by the number of the automated test equipment used (where applicable). 

The result of each required test must be recorded on preprinted or computerized forms designed 

for that purpose, or by electronic means, subject to approval by the FRA Associate Administrator 

for Railroad Safety/Chief Safety Officer. Results of the tests must be recorded in the manner 

prescribed by the rule. 

The form must show name of carrier, place, date, equipment tested, results of tests, repairs, 

replacements, adjustments, condition in which apparatus was left, and signature of the employee 

making the tests, or electronically coded or identified by a unique number of the automated test 

equipment used (where applicable). This required information may be shown in any order the 

carrier chooses and forms may provide for several tests. Equipment tested refers to each piece of 

equipment tested in compliance with 49 CFR §§ 236.102 to 236.109, inclusive; 236.376 to 

236.387, inclusive; 236.576; 236.577; 236.586 to 236.589, inclusive; and 236.917(a). 

Each test record required by this rule shall be filed in the office of a supervisory official having 

jurisdiction. The divisional officer may be an assistant signal supervisor, signal supervisor, or 

any other divisional officer. ATC, ATS, and ACS test records shall be kept at the locomotive 

office nearest to the test point locations. 

Except for the results of tests made in compliance with §§ 236.587 and 236.917(a), all such 

records of tests shall be kept on file until the next record of the same tests are made and put on 

file. The records of tests made at intervals of less than 1 year shall be retained for at least 1 year. 

The records of results of tests made in compliance with § 236.587 shall be kept on file for at least 

92 days. 

The records for results of inspections and tests made in compliance with § 236.917(a) must be 

retained as follows: 

1. Results of inspections and tests that pertain to installation or modification must be 

retained for the life-cycle of the equipment tested and may be kept at any designated 

office on the railroad. 

2. Results of periodic inspections and tests required for maintenance or repair of the 

equipment inspected and tested must be retained until the next record is filed but in no 

case less than 1 year. 

FRA requires that railroads adopting electronic means of recording test results first obtain FRA’s 
236-62 

approval through an electronic recordkeeping approval process. Requiring FRA approval will 

establish a process whereby FRA can ensure all the proper information (prescribed in paragraph 

(a)) is recorded. FRA will also be able to determine where and how the electronic records will 

be available for inspection. FRA notes that if tests are performed by automatic test equipment 

(ATE), the test equipment shall be identified by a unique number, and the test record must reflect 

that number. 

Any railroad wanting to implement electronic recordkeeping is required to obtain approval from 

FRA’s Associate Administrator for Railroad Safety/Chief Safety Officer. This process consists 

of a railroad submitting to FRA’s Signal and Train Control Division Staff Director the following 

information: 

1. An action plan with a schedule for the implementation of the system. 

2. A copy of the recordkeeping forms indicating how the results of all the applicable 

inspections or tests will be electronically recorded. 

3. A copy of the instruction or procedure manual for the use of the system. 

FRA will then review the materials and subsequently notify the railroad of the result of our 

approval process. 

Electronic or automated tracking systems used to meet the requirements contained in paragraph 

(a) of this section must be capable of being reviewed and monitored by FRA at any time to 

ensure the integrity of the system. FRA’s Associate Administrator for Railroad Safety/Chief 

Safety Officer may prohibit or revoke a railroad’s authority to use an electronic or automated 

tracking system in lieu of preprinted forms if FRA finds that the electronic or automated tracking 

system is not properly secured; is inaccessible to FRA, FRA-certified State inspectors, or 

railroad employees requiring access to discharge their assigned duties; or fails to adequately 

track and monitor the equipment. The Associate Administrator for Railroad Safety/Chief Safety 

Officer will provide the affected railroad with a written statement of the basis for the 

decision prohibiting or revoking the railroad from using an electronic or automated tracking 

system. (See Technical Bulletin S-96-05)

CLASSIFICATION OF DEFECTS

236.110.A1 Record of the results of tests not made. 

236.110.A2 Record of the results of tests not recorded on prescribed form. 

236.110.A3 Record of the results of tests recorded by unapproved electronic means. 

236.110.A4 Record of the results of tests not complete. 

236.110.A5 Record of the results of test does not show name of railroad, place and date, 

equipment tested, results of tests, repairs, replacements, adjustments made, 

condition in which apparatus was left. 
236-63 

236.110.A6 Record of the results of test is not signed or electronically coded by the employee 

making the test, or identified by the unique number of the automated test 

equipment performing the test (where applicable). 

236.110.A7 Record of the results of tests not filed with a supervisory official having 

jurisdiction. 

236.110.A8 Record of the results of tests not available for inspection and replication during 

normal business hours. 

236.110.B1 Record of the results of tests made in compliance with § 236.587 not retained for 

92 days. 

236.110.C1 Record of the results of inspections and tests required by § 236.917(a) for 

installation or modification not retained for the life-cycle of the equipment or filed 

in designated railroad office. 

236.110.C2 Record of the results of periodic inspections and tests required by § 236.917(a) for 

maintenance or repair of the equipment not retained until next record is filed but 

in no case less than one year. 

236.110.D1 Record of the results of all tests listed in paragraph (a) of this section not retained 

until next record is filed but in no case less than one year. 

236.110.E1 Electronic or automatic tracking system used to meet the requirements contained 

in paragraph (a) of this section is not properly accessible by FRA, or FRAcertified State inspectors. 

236.110.E2 Electronic or automatic tracking system used to meet the requirements contained 

in paragraph (a) of this section is not properly secured. 

236.110.E3 Electronic or automatic tracking system used to meet the requirements contained 

in paragraph (a) of this section is not properly accessible to railroad employees 

requiring access to discharge their assigned duties. 

236.110.E4 Electronic or automatic tracking system used to meet the requirements contained 

in paragraph (a) of this section fails to adequately track and monitor the 

equipment. 

Subpart B – Automatic Block Signal Systems 

Standards 

§ 236.201 Track circuit, control of signals. 

 The control circuits for home signal aspects with indications more favorable than “proceed at 

restricted speed” shall be controlled automatically by track circuits extending through the entire 

block.
236-64 

Application: 

This rule requires that aspects of signals with indications more favorable than “proceed at 

restricted speed” be controlled automatically by track circuits extending through the entire block. 

This rule applies to automatic block and traffic control systems. 

Title 49 CFR § 236.708 requires the limits of the block be defined for the last signal. This may 

be accomplished by the use of wayside signage, or by specific designation in the carrier’s 

timetable or special instructions. 

The aspect and indication determine compliance with this rule. A carrier is in noncompliance if 

any aspect with an indication more favorable than “proceed at restricted speed” is used, even 

though the speed may be 20 mph or less. 

A block extends from signal to signal, or from a signal to its defined limits at end of the system. 

This rule is not applicable to so-called distant or approach signals outside of a system. 

CLASSIFICATION OF DEFECTS

236.201.A1 The control circuits for home signal aspects more favorable than “proceed at 

restricted speed" not controlled automatically by track circuits extending through 

the entire block. 

§ 236.202 Signal governing movements over hand-operated switch. 

 Signal governing movements over hand-operated switch in the facing direction shall display 

its most restrictive aspect when the points are open one-fourth inch or more and, in the trailing 

direction, three-eighths inch or more, except that where a separate aspect is displayed for facing 

movements over the switch in the normal and in the reverse position, the signal shall display its 

most restrictive aspect when the switch points are open one-fourth inch or more from either the 

normal or reverse position.

Application: 

Signal governing movements over hand-operated switch is required to display its most restrictive 

aspect when the points are not in the proper position. This rule applies to both automatic block 

and traffic control systems. 

This rule requires each switch to be so interconnected with the signal system so that when the 

switch is not in proper position, each signal governing movements over the switch will display 

its most restrictive aspect. 

This rule does not apply to spring switches. 

This rule is a signal system design requirement and it applies to the circuitry necessary to comply 

with the requirements of the rule, but does not apply to defective conditions such as circuit 

controller adjustments, absence of shunt wires, etc. 
236-65 

CLASSIFICATION OF DEFECTS

236.202.A1 Signal does not display its most restrictive aspect when points of facing-point 

hand-operated switch over which it governs movements are open one-fourth inch 

or more. 

236.202.A2 Signal does not display its most restrictive aspect when points of trailing-point 

hand-operated switch over which it governs movements is open three-eighths inch 

or more. 

236.202.A3 Signal which displays a separate aspect for facing movements over hand-operated 

switch in the normal and in the reverse position does not display its most 

restrictive aspect when the switch points are open one-fourth inch or more from 

either the normal or reverse position. 

§ 236.203 Hand-operated crossover between main tracks; protection.

 At hand-operated crossover between main tracks, protection shall be provided by one of the 

following: 

 (a) An arrangement of one or more track circuits and switch circuit controllers, 

 (b) Facing-point locks on both switches of the crossover, with both locks operated by a single 

lever, or 

 (c) Electric locking of the switches of the crossover. Signals governing movements over 

either switch shall display their most restrictive aspect when any of the following conditions 

exist: 

 (1) Where protection is provided by one or more track circuits and switch circuit controllers, 

and either switch is open or the crossover is occupied by a train, locomotive or car in such a 

manner as to foul the main track. It shall not be a violation of this requirement where the 

presence of sand, rust, dirt, grease, or other foreign matter on the rail prevents effective shunting; 

 (2) Where facing-point locks with a single lever are provided, and either switch is unlocked; 

 (3) Where the switches are electrically-locked, before the electric locking releases.

Application: 

This rule requires that hand-operated crossover between main tracks provide protection for train 

movements by either an arrangement of one or more track circuits and switch circuit controllers, 

facingpoint locks on both switches operated from a single lever, or electric locks on both switches of 

the crossover. 

Signals governing movements over either switch must display their most restrictive aspect where 

switch circuit controller and track circuits are used, when either switch is not in proper position, 

or the crossover is occupied by a train, locomotive, or car; where facing-point locks are used, 

either switch is unlocked; and, where electric locks are used, before the electric locking releases. 

Relief is provided for certain conditions adverse to shunting. 

This rule applies to both automatic block and traffic control systems. 
236-66 

Relief of the shunting requirements does not exceed that of § 236.51. Where such conditions are 

known to exist, adequate measures to safeguard train operation must be taken. 

These requirements apply to crossovers between main tracks in either automatic block or traffic 

control territory, and between a main track and a signaled siding in traffic control territory. 

Time or approach locking must be provided for electric locking. 

Inspectors should be alert for staggered insulated rail joints that will permit undetected 

occupancy by a locomotive or car, where one or more track circuits and circuit controllers are 

used. Such defective conditions are prohibited by § 236.51. 

Arrangements meeting the requirements of paragraph (2) or (3) do not require the use of track 

circuits. 

This rule prohibits the use of only shunt fouling circuits to provide protection against the 

occupancy of the turnouts between the two main tracks. 

CLASSIFICATION OF DEFECTS

236.203.A1 At hand-operated crossover between main tracks, protection is not provided by 

one of the following: (1) An arrangement of track circuits and switch circuit 

controllers; (2) facing-point locks on both switches of the crossover, with both 

locks operated by a single lever; or, (3) electric locking of the switches of the 

crossover. 

236.203.C1 Signal governing movements over switch of hand-operated crossover between 

main tracks does not display its most restrictive aspect when either switch of the 

crossover is open, where crossover protection is provided by track circuits and 

switch circuit controllers. 

236.203.C2 Signal governing movements over switch of hand-operated crossover between 

main tracks does not display its most restrictive aspect when crossover is 

occupied by a train, locomotive, or car in such manner as to foul the main track, 

where crossover protection is provided by track circuits and switch circuit 

controllers. (Fully explain the condition of rail with respect to presence of sand, 

rust, dirt, grease, or other foreign matter.) 

236.203.C3 Signal governing movements over switch of hand-operated crossover between 

main tracks does not display its most restrictive aspect when either switch of 

crossover is unlocked, where switches of crossover are provided with facing-point 

locks operated by a single lever. 

236.203.C4 Signal governing movements over switch of hand-operated crossover between 

main tracks does not display its most restrictive aspect before electric locking 

releases, where switches are electrically locked. 

236.203.C5 Electric locking releases before the expiration of predetermined time interval after 

signals display their most restrictive aspect. (Applies only to electric locking of 

switches of hand-operated crossover between main tracks.) 
236-67 

§ 236.204 Track signaled for movements in both directions, requirements. 

 On track signaled for movements in both directions, a train shall cause one or more opposing 

signals immediately ahead of it to display the most restrictive aspect, the indication of which 

shall be not more favorable than “proceed at restricted speed.” Signals shall be so arranged and 

controlled that if opposing trains can simultaneously pass signals displaying proceed aspects and 

the next signal in advance of each such signal then displays an aspect requiring a stop, or its most 

restrictive aspect, the distance between opposing signals displaying such aspects shall be not less 

than the aggregate of the stopping distances for movements in each direction. Where such 

opposing signals are spaced stopping distance apart for movements in one direction only, signals 

arranged to display restrictive aspects shall be provided in approach to at least one of the signals. 

Where such opposing signals are spaced less than stopping distance apart for movements in one 

direction, signals arranged to display restrictive aspects shall be provided in approach to both 

such signals. In absolute permissive block signaling, when a train passes a 

head block signal, it shall cause the opposing head block signal to display an aspect with an 

indication not more favorable than “stop.”

Application: 

This rule requires that on track signaled for movements in both directions a train shall cause one 

or more opposing signals ahead of it to display the most restrictive aspect. Signals are required 

to be spaced or arranged to provide stopping distance for opposing trains. 

In absolute permissive block signaling, when a train passes a head block signal, it must cause the 

opposing head block signal to display an aspect indicating not more favorable than “stop.” 

Head block signal is defined by Part 1.1.1 of the AAR Signal Manual as “a home signal 

governing entrance into the block between sidings on single track.” 

Braking distances should be obtained from the carrier’s braking distance chart. 

CLASSIFICATION OF DEFECTS

236.204.A1 On track signaled for movements in both directions a train does not cause one or 

more opposing signals immediately ahead of it to display the most restrictive 

aspect the indication of which is not more favorable than "proceed at restricted 

speed." 

236.204.A2 On track signaled for movements in both directions where opposing signals are 

spaced stopping distance apart for movements in one direction only, signals not 

arranged so that a restrictive aspect will be displayed by an least one of the signals 

in approach of the opposing signals, when such approach signals are passed 

simultaneously by opposing trains. 

236.204.A3 On track signaled for movements in both directions where opposing signals are 

spaced less than stopping distance apart for movements in one direction, signals 

not arranged so that restrictive aspects will be displayed by both signals in 

approach of the opposing signals for trains passing such approach signals 

simultaneously. 
236-68 

236.204.A4 In APB signaling, train passing head block signal does not cause opposing head 

block signal to display an aspect with an indication not more favorable than 

“stop.” 

§ 236.205 Signal control circuits; requirements.

 The circuits shall be so installed that each signal governing train movements into a block will 

display its most restrictive aspect when any of the following conditions obtain within the block: 

 (a) Occupancy by a train, locomotive, or car, 

 (b) When points of a switch are not closed in proper position, 

 (c) When an independently-operated fouling-point derail equipped with switch circuit 

controller is not in derailing position, 

 (d) When a track relay is in deenergized position or a device which functions as a track relay 

is in its most restrictive state; or when signal control circuit is deenergized.

Application: 

Control circuits are required to be installed so that each signal will display its most restrictive 

aspect when the block it governs is occupied by a train, locomotive, or car; a switch is not in 

proper position; an independently operated derail equipped with switch circuit controller is not in 

derailing position; a track relay is in deenergized position or a device that functions as a track 

relay is in its most restrictive state; or when a signal control circuit is deenergized. 

This rule applies to both automatic block signal and traffic control systems. 

A signal must display its most restrictive aspect when any of the conditions listed under (a), (b), 

(c), or (d) of this rule occur. However, it is permissible, after the signal’s most restrictive aspect 

has been displayed for such conditions, for a pushbutton, switch, lever, or other device to be 

operated manually by the operator or trainman and an indication not more favorable than 

“proceed at restricted speed” then be obtained. 

This rule is applicable to the design and installation of control circuits, and does not apply to 

defective conditions which appear to affect this rule, such as circuit controller adjustments, 

missing shunt or fouling wires, dead section, track circuit adjustments, grounds, etc. 

This rule does not require that the most restrictive aspect be a red or a stop indication. 

CLASSIFICATION OF DEFECTS

236.205.A1 Circuits not so installed that signal will display its most restrictive aspect when 

the block into which it governs train movements is occupied by a train, 

locomotive, or car. 

236.205.B1 Circuits not so installed that signal will display its most restrictive aspect when 

points of a switch in the block into which it governs train movements are not 

closed in proper position. 

236.205.C1 Circuits not so installed that signal will display its most restrictive aspect when an 

independently operated fouling-point derail equipped with switch circuit 
236-69 

controller in the block into which it governs train movements is not in derailing 

position. 

236.205.C2 Circuits not so installed that signal will display its most restrictive aspect when a 

track relay within the block into which it governs train movements is in 

deenergized position. 

236.205.C3 Circuits not so installed that signal will display its most restrictive aspect when a 

device that functions as a track relay within the block into which it governs train 

movements is in its most restrictive state. 

236.205.C4 Circuits not so installed that signal will display its most restrictive aspect when its 

control circuit is deenergized. 

§ 236.206 Battery or power supply with respect to relay; location.

 The battery or power supply for each signal control relay circuit, where an open-wire circuit 

or a common return circuit is used, shall be located at the end of the circuit farthest from the 

relay.

Application: 

This rule requires that the source of energy be located at the end of the circuit farthest from the 

relay, where open-wire circuit or common return circuit is used. 

This rule applies to automatic block signal and traffic control systems. (It does not apply to 

interlockings.) 

This rule prohibits the use of loop circuits in vital circuitry. 

CLASSIFICATION OF DEFECTS

236.206.A1 Battery or power supply for signal control relay circuit not located at the end of 

the circuit farthest from the relay. (Applies only to open-wire circuit or common 

return circuit.) 

§ 236.207 Electric lock on hand-operated switch; control.

 Electric lock on hand-operated switch shall be controlled so that it cannot be unlocked until 

control circuits of signals governing movements over such switch have been opened. Approach 

or time locking shall be provided.

Application: 

Electric locks on hand-operated switches are prohibited from being unlocked before control 

circuits of signals governing movement over switches are opened. 

Approach or time locking must be provided. 

This rule is applicable only to automatic block signal systems. 
236-70 

There are no requirements for the installation of electric locks in automatic block signal territory. 

However, if an electric lock is installed on a hand-operated switch in automatic block signal 

territory, the electric lock must comply with this rule, including the provision that approach or 

time locking be provided. The testing requirements for approach and time locking do not apply 

to automatic block signal systems, therefore the carrier is not required to make periodic tests of 

the approach or time locking within automatic block signal systems. 

CLASSIFICATION OF DEFECTS

236.207.A1 Electric lock on hand-operated switch can be unlocked before control circuits of 

signals governing movements over such switch have been opened. 

236.207.A2 Approach or time locking not provided for electric lock on hand-operated switch. 

236.207.A3 Electric lock on hand-operated switch can be unlocked before expiration of 

predetermined time interval where time locking is provided. 

236.207.A4 Electric lock on hand-operated switch can be unlocked before expiration of 

predetermined time interval with approach circuit occupied where approach 

locking is provided. 

236.207.A5 Approach locking not effective. 

236.207.A6 Time locking not effective. 

236.207.A7 Approach or time locking of electric lock on hand-operated switch can be 

defeated by the unauthorized use of emergency device which is not kept sealed in 

the non-release position. 

Subpart C – Interlocking 

Standards 

§ 236.301 Where signals shall be provided.

 Signals shall be provided to govern train movements into and through interlocking limits, 

except that a signal shall not be required to govern movements over a hand-operated switch into 

interlocking limits if the switch is provided with an electric lock and a derail at the clearance 

point, either pipe-connected to the switch or independently locked, electrically. Electric locks 

installed under this rule must conform to the time and approach locking requirements of Rule 

314 (without reference to the 20 mile per hour exceptions), and those of either Rule 760 or Rule 

768, as may be appropriate.

Application: 

This rule requires that a signal be provided to govern train movements into and through 

interlocking limits, except over electrically locked hand-operated switch equipped with either a 

pipe-connected derail or independently operated electrically locked derail. 
236-71 

This rule applies to interlocking only. It does not apply to controlled points in traffic control 

systems. 

Electric locks installed under this rule must conform to requirements of Rules 314, 760, and 768, 

without regard to speed. 

All interlocked signals must be operative unless relief has been heretofore granted. The word 

“into” is defined as “to or toward the inside of from outside; past or through the outer boundary 

or limit.” The word “through” is defined as, “into one side, end, or point and out of the other.” 

Therefore, an inoperative red signal aspect does not meet these requirements. 

Signals shall be provided to govern movements into and through interlocking limits. A carrier 

using inoperative red signal aspects for movement of trains or engines into and through 

interlocking limits is not in compliance. 

A signal is not required to govern movements over a hand-operated switch into interlocking 

limits if the hand-operated switch is equipped with an electric lock and a derail is provided at the 

clearance point that is either pipe-connected or locked electrically. There are no restrictions on 

train speed at such installations. 

A non-electrically locked switch without derail may be utilized within interlocking limits 

provided a signal is provided to govern movements on all routes, and speed over the switch does 

not exceed 20 mph. 

An electrically locked switch without derail, but with signal governing movements out of the 

switch, may be utilized without restriction on train speed. 

Where an electrically locked switch and/or derail is used within the interlocking, locking must 

protect against all possible conflicting routes, and once the locking has been released, it should 

be impossible to clear a conflicting route. 

All electrically locked switches and derails within interlocking limits must have approach or time 

locking. 

CLASSIFICATION OF DEFECTS

236.301.A1 Signal not provided to govern train movements into and through interlocking 

limits. (Note: This does not apply to a turnout over a hand-operated switch into 

interlocking limits if the switch is provided with an electric lock and a derail at 

the clearance point, either pipe-connected to the switch or independently locked, 

electrically. Electric locks installed under this rule must conform to the time and 

approach locking requirements of 

§ 236.314 (without reference to the 20 mph exceptions), and those of either § 

236.760 or 

§ 236.768, as may be appropriate). 
236-72 

§ 236.302 Track circuits and route locking.

 Track circuits and route locking shall be provided and shall be effective when the first pair of 

wheels of a locomotive or a car passes a point not more than 13 feet in advance of the signal 

governing its movement, measured from the center of the mast, or if there is no mast, from the 

center of the signal.

Application: 

This rule requires track circuits and route locking where power-operated switches are used, be 

provided throughout interlocking limits. This rule applies to interlocking only. 

Route locking shall be effective at a point not more than 13 feet in advance of the signal, 

measured from the center of the signal mast portion on which it is mounted (e.g., from center of 

tall mast, or from center of offset or extension mast), or if there is no mast, from the center of the 

signal. 

When a train or engine passes a signal displaying any type of proceed indication, including 

“proceed at restricted speed,” track circuits and route locking shall be provided. Electric locking, 

either in the interlocking machine or the wayside equipment, that prevents the movement of any 

switch, movable-point frog, or derail in the route entered, is required. However, it may be so 

arranged that after a train clears a track section of the route, the locking affecting that section 

may be released. 

Route locking is not required nor provided where there is an absence of a power-operated switch, 

movable-point frog, or derail in the route. Route locking is also not required by this rule in an 

instance of a train crew receiving permission to pass a stop signal indication (i.e., occupancy of 

the track circuit alone not locking the switch). Where any location is found not having the 

equivalent of route locking in that instance, and it is equipped with one or more dual-controlled 

power-operated switches, assurance should be gained that the carrier’s special instructions for 

hand-operation of such a switch provides for the safe 

movement of trains (e.g., the switch may not be restored to power operation until the rear of the 

train has passed over and beyond it). 

CLASSIFICATION OF DEFECTS

236.302.A1 Track circuits not provided throughout interlocking limits. 

236.302.A2 Route locking not provided throughout interlocking limits. (Note: Route locking 

shall be effective when the first pair of wheels of a locomotive or car passes a 

point not more than 13 feet in advance of the signal governing the movement.) 

236.302.A3 Route locking not effective. 

§ 236.303 Control circuits for signals, selection through circuit controller operated by 

switch points or by switch locking mechanism. 

 The control circuit for each aspect with indication more favorable than "proceed at restricted 

speed'' of power-operated signal governing movements over switches, movable-point frogs, and 

derails shall be selected through circuit controller operated directly by switch points or by switch 
236-73 

locking mechanism, or through relay controlled by such circuit controller, for each switch, 

movable-point frog, and derail in the routes governed by such signal. Circuits shall be arranged 

so that such signal can display an aspect indicating more favorable than “proceed at restricted 

speed,” only when each switch, movable-point frog, and derail in the route is in proper position.

Application: 

This rule is a standard that requires control circuits of signal aspects with indications more 

favorable than “proceed at restricted speed” be selected through switch circuit controller or relay 

controlled by circuit controller of each hand-operated, power-operated, or mechanically-operated 

switch; movable-point frog; or derail in the route governed. It requires each switch, movablepoint frog, or derail to be in proper position before such signal aspect can be displayed. 

This rule applies to both interlocking and traffic control systems. It is not applicable to control 

circuits of aspects indicating “proceed at restricted speed.” 

Each switch, movable-point frog, or derail shall be equipped with a switch circuit controller 

operated directly by the switch points or by a circuit controller operated by a switch locking 

mechanism. An aspect 

with an indication more favorable than “proceed at restricted speed” must be selected through 

such switch, movable-point frog, or derail circuit controller, or through a relay controlled by the 

circuit controller. 

This rule applies to all hand-operated, power-operated, or mechanically-operated switches within 

interlockings or traffic control systems. These include power-operated switches of any kind, 

(electric, electro-pneumatic, or hydraulic) and pipe-connected switches operated from a lever of 

a mechanical interlocking machine. 

Noncompliance with this rule should be reflected in indication locking tests for power-operated 

switches, movable-point frogs, and derails. Test hand-operated switches by opening contacts of 

switch circuit controller. 

Title 49 CFR § 236.6 is a maintenance standard that is applicable to hand-operated switches, 

(both electrically locked and non-electrically locked). 

Title 49 CFR § 236.13 is a design standard that is applicable to spring switches installed in 

interlockings, traffic control systems, and automatic block signal systems. This rule prescribes 

the requirements for signal control circuits governing facing-point movements where spring 

switches are installed in interlockings, traffic control, and automatic block signal systems. It 

should be noted that 49 CFR 

§ 236.13 does not require the signal control circuits for aspects governing trailing movements 

over a spring switch to check the position of the switch points. 

Title 49 CFR §§ 236.334 and 236.342 are maintenance standards that dictate that the circuit 

controllers be maintained in such condition as to fulfill the requirements of 49 CFR § 236.303. 

The combination of indication and/or mechanical locking, as provided by an electro-mechanical 

interlocking machine, does not comply with this rule. A circuit controller is required at each 

switch through which control circuits of aspects with an indication of more favorable than 

“proceed at restricted speed” must be selected. 
236-74 

Switch selection circuits are required for each aspect of a power-operated signal with an 

indication more favorable than “proceed at restricted speed” regardless of whether the speed 

through the interlocking is restricted by carrier operating rule or civil speed restriction. 

CLASSIFICATION OF DEFECTS

236.303.A1 Control circuit for signal aspect with indication more favorable than “proceed at 

restricted speed” of power-operated signal governing movements over switches, 

movable-point frogs, and derails not selected through circuit controller operated 

directly by switch points or by switch locking mechanism, or through relay 

controlled by such switch circuit controller on each switch, movable-point frog, 

and derail in the routes governed by the signal. 

236.303.A2 Control circuit for signal aspect with indication more favorable than “proceed at 

restricted speed” is not so arranged that such aspect can only be displayed by a 

signal when each switch, movable-point frog, and derail in the route governed is 

in proper position. 

§ 236.304 Mechanical locking or same protection effected by circuits.

 Mechanical locking, or the same protection effected by means of circuits, shall be provided.

Application: 

This rule requires that mechanical locking, or the equivalent protection by means of circuits, be 

provided at each interlocking. 

Each interlocking is required to be arranged either mechanically and/or electrically so that the 

operation of controlling devices or apparatus must succeed each other in proper sequence before 

any proceed indication can be displayed. 

CLASSIFICATION OF DEFECTS

236.304.A1 Mechanical locking, or the same protection effected by means of circuits, not 

provided. 

§ 236.305 Approach or time locking.

 Approach or time locking shall be provided in connection with signals displaying aspects 

with indications more favorable than “proceed at restricted speed.”

Application: 

This rule requires approach or time locking must be provided in connection with any interlocking 

signals displaying aspects with indications more favorable than “proceed at restricted speed.” 

This is applicable to any aspect indicating more favorable than “proceed at restricted speed” no 

matter what speed restriction the carrier has on the track. For example, a green aspect 

interlocking signal that does not have approach or time locking, where the speed is 10 mph, does 

not comply with these requirements. 
236-75 

This rule requires that the approach or time locking be effective for the maximum authorized 

speed permitted on each route. 

CLASSIFICATION OF DEFECTS

236.305.A1 Approach or time locking not provided in connection with signal displaying 

aspects with indication more favorable than “proceed at restricted speed.” 

236.305.A2 Approach locking not effective. 

236.305.A3 Time locking not effective. 

§ 236.306 Facing-point lock or switch-and-lock movement.

 Facing-point lock or switch-and-lock movement shall be provided for mechanically-operated 

switch, movable-point frog, or split-point derail.

Application: 

Facing-point lock or switch-and-lock movement is required for mechanically-operated switch, 

movable-point frog, or split-point derail. 

Mechanically-operated, as applied to this part, refers to a switch, movable-point frog, or splitpoint derail operated by the control operator from a central point by means of pipe connection. It 

would also apply to a mechanically-operated cabin-type interlocking with the appurtenances 

operated by trainmen. It does not apply to hand-operated derails or switches. 

CLASSIFICATION OF DEFECTS

236.306.A1 Facing-point lock or switch-and-lock movement not provided for mechanicallyoperated switch, movable-point frog, or split-point derail. 

§ 236.307 Indication locking.

 Indication locking shall be provided for operative approach signals of the semaphore type, 

power-operated home signals, power-operated switches, movable-point frogs, and derails, and 

for all approach signals except light signals, all aspects of which are controlled by polar or coded 

track circuits or line circuits so arranged that a single fault will not permit a more favorable 

aspect than intended to be displayed.

Application: 

This rule requires indication locking for operative approach signals of the semaphore type, 

power-operated home signals, power-operated switches, movable-point frogs, and derails, and 

for all approach signals, except light signals with all aspects controlled by polar or coded track 

circuits, or line circuits so installed that a single fault will not permit a more favorable aspect 

than intended to be displayed. 

This rule applies to both interlocking and traffic control systems. 
236-76 

Indication locking is electric locking which assures that the operation of signal appliances 

succeed each other in proper sequence. Indication locking falls into three primary categories: 

levers, signals, and switches. 

Depending upon the type of interlocking machine, indication locking of levers prevents the lever 

from being operated full-stroke until the operated unit has properly completed its movement, or 

prevents the final lever from being operated until all units have properly completed their required 

movements. 

Indication locking of home signals prevents the established route from being changed. It 

prevents the operation of all switches, movable-point frogs, derails, and other operative units in 

the route, and prevents the clearing of conflicting signals. Indication locking of approach signals 

prevents the route governed by a home signal from being changed until the associated approach 

signal displays an aspect not more favorable than “Approach Next Signal Prepared to Stop.” 

Indication locking of switches, movable-point frogs, derails, and other operative units, such as 

bridge locking members, prevents the clearing of signals governing movements over the unit 

until each operative unit has completed its required movement. 

Inoperative approach signals, and mechanically operated (pipe-connected) home signals and 

switches, are excluded from these requirements. 

Each operative approach signal of the semaphore type, power-operated home signal, poweroperated switch, movable-point frog, or derail is required to be provided with indication locking. 

Each operative approach signal of the light type shall be provided with indication locking, except 

where its aspects are controlled by polar or coded track circuits, or by line circuits so arranged 

that a single fault will not permit a false proceed signal to be displayed. A line circuit is not so 

arranged if a short between two wires on the line, regardless of their position, results in a more 

favorable aspect than intended to be displayed on the approach signal. 

CLASSIFICATION OF DEFECTS

236.307.A1 Indication locking not provided for semaphore type operative approach signal. 

236.307.A2 Indication locking not provided for power-operated home signal. 

236.307.A3 Indication locking not provided for power-operated switch, movable-point frog, 

or derail. 

236.307.A4 Indication locking not provided for approach signal of the light type. (Applies to 

each light signal except light signal all aspects of which are controlled by polar or 

coded track circuits or line circuits so arranged that a single fault will not permit a 

more favorable aspect than intended to be displayed.) 

236.307.A5 Single fault in line circuit controlling approach signal aspect, where indication 

locking is not provided, permits more favorable aspect than intended to be 

displayed. 

236.307.A6 Indication locking not effective. 
236-77 

§ 236.308 Mechanical or electric locking or electric circuits; requisites.

 Mechanical or electric locking or electric circuits shall be installed to prevent signals from 

displaying aspects which permit conflicting movements except that opposing signals may display 

an aspect indicating proceed at restricted speed at the same time on a track used for switching 

movements only, by one train at a time. Manual interlocking in service as of the date of this part 

at which opposing signals on the same track are permitted simultaneously to display aspects 

authorizing conflicting movements when 

interlocking is unattended, may be continued, provided that simultaneous train movements in 

opposite directions on the same track between stations on either side of the interlocking are not 

permitted. 

 

 Note: Relief from the requirement of this section will be granted upon an adequate showing 

by an individual carrier to allow opposing signals on the same track simultaneously to display 

aspects to proceed through an interlocking which is unattended, provided that train movements in 

opposite directions on the same track between stations on either site of the interlocking are not 

permitted at the same time.

Application: 

This rule prohibits display of conflicting permissive aspects, except opposing signals on track 

used for switching movements only by one train at a time. Manual interlockings installed prior 

to October 1, 1950, are excluded, provided simultaneous opposing movements are not permitted 

between stations on either side of the interlocking when it is unattended. 

Mechanical locking, electric locking, or electric circuits are required to be installed so that 

signals cannot display aspects that permit conflicting movements. 

Opposing signals on track used for switching movements only are excluded and may display 

aspects indicating “Proceed at Restricted Speed” when used by only one train at a time. This 

arrangement is prohibited for use by through trains. It is prohibited for more than one switch 

crew to perform movements on track used for switching only. 

This rule applies to interlockings only. 

Unattended manual interlockings having signals that display conflicting aspects that are 

interconnected with automatic block signal systems meet the requirements of this rule. 

CLASSIFICATION OF DEFECTS

236.308.A1 Signals can display aspects which permit conflicting movements. (Does not apply 

to signals that may display restricting aspects at the same time on a track used for 

switching movements only, by one train at a time, or to opposing signals on the 

same track at manual interlocking which are permitted simultaneously to display 

aspects authorizing conflicting 

 movements when interlocking is unattended, provided that simultaneous train 

movements in opposite directions on the same track between stations on either 

side of the interlocking are not permitted.) 
236-78 

§ 236.309 Loss of shunt protection; where required. 

 (a) A loss of shunt of 5 seconds or less shall not permit an established route to be changed at 

an automatic interlocking. 

 (b) A loss of shunt of 5 seconds or less shall not permit the release of the route locking circuit 

of each power-operated switch hereafter installed.

Application: 

This rule requires that a loss of shunt of 5 seconds or less, regardless if it occurs on the approach 

circuit or on a track circuit within the limits of an automatic interlocking, must not permit the 

established route to 

be changed. It also requires that a loss of shunt of 5 seconds or less shall not permit the release 

of route locking. 

This rule applies to all automatic interlockings whether or not they are connected to other signal 

systems, and to traffic control systems. Automatic drawbridges, manual interlockings arranged 

for automatic operation when unattended, and interlockings having both automatic and 

controlled routes are included. This rule is applicable to route locking of any power-operated 

switch installed after February 26, 1984. 

Test for compliance on approach circuits that activate approach locking should be made by 

placing a shunt on the approach circuit to establish a route. The route is established when the 

interlocked signal displays an aspect authorizing movement into interlocking limits. After the 

route is established, remove the shunt while observing the interlocked signal to assure its aspect 

does not change until the expiration of more than 5 seconds. Each track circuit in the approach 

circuit should be tested. 

Test for compliance on approach circuits that activate time locking should be made by placing a 

shunt on the approach circuit to establish a route. The route is established when the interlocked 

signal displays an aspect authorizing movement into interlocking limits. After the route is 

established, remove the shunt and determine that when the interlocked signal obtains an aspect 

indicating stop, a predetermined time 

interval is activated which prevents the clearing of a conflicting signal or operation of an 

interlocked device. Each track circuit in the approach circuit should be tested. 

Test for compliance on track circuits within interlocking limits should be conducted by making 

an operating shunt test into interlocking limits, then place a shunt on the approach circuit of a 

conflicting route. Remove the shunt from the track circuit within interlocking limits while 

observing the conflicting route home signal to assure it does not clear until after the expiration of 

more than 5 seconds. Each track circuit within interlocking limits should be tested. 

Test for compliance at a power-operated switch should be conducted by clearing the signal 

governing movement over the switch; place a shunt on the track circuit in approach to the signal; 

place a shunt on the track circuit in advance of signal; remove shunt from the track circuit in 

approach to signal; remove shunt in advance of the signal, and determine that the switch cannot 

be operated until after the expiration of more than 5 seconds. If more than one track circuit is in 

the route locking circuit, check each circuit in turn. 
236-79 

CLASSIFICATION OF DEFECTS

236.309.A1 Loss of shunt of 5 seconds or less permits established route at automatic 

interlocking to be changed. (This includes automatic drawbridges, manual 

interlockings arranged for automatic operation when unattended, and 

interlockings having both automatic and controlled routes.) 

236.309.B1 Loss of shunt of 5 seconds or less permits the release of route locking of poweroperated switch, movable-point frog, or derail. (Does not apply to poweroperated switch, movable-point frog, or derail installed prior to February 27, 

1984.) 

§ 236.310 Signal governing approach to home signal.

 A signal shall be provided on main track to govern the approach with the current of traffic to 

any home signal except where the home signal is the first signal encountered when leaving yards 

or stations and authorized speed approaching such signal is not higher than slow speed. When 

authorized speed 

between home signals on route governed is 20 miles per hour or less, an inoperative signal 

displaying an aspect indicating “approach next signal prepared to stop” may be used to govern 

the approach to the home signal.

Application: 

This rule requires that a signal be provided on main track to govern the approach with the current 

of traffic to any home signal. It excludes the condition where the home signal is the first signal 

encountered when leaving yards or stations and the authorized speed approaching the home 

signal is not higher than slow speed. It provides for use of an inoperative approach signal when 

authorized speed between home signals on route governed is 20 mph or less. 

This rule applies to both interlocking and traffic control systems. 

A signal to govern the approach to a home signal is required on main track only. Auxiliary 

tracks are excluded regardless of how heavily traveled. 

An approach signal is required for current of traffic only, where normal operation is with the 

current of traffic. 

A signal is not required to govern the approach to a home signal where it is the first signal 

encountered when leaving a yard or station where all trains originate or stop if the authorized 

speed approaching the first signal encountered is not higher than slow speed. If trains are 

operated that do not stop at the yard or station, an approach signal must be provided. In addition, 

the home signal being the first signal encountered must be within yard or station limits. If it is 

outside yard or station limits, it becomes the first signal encountered after leaving the yard or 

station, and requires that an approach signal be provided. 

Where speed between home signals of an interlocking or controlled point exceeds 20 mph, an 

operative approach signal must be provided. 

An operative approach signal must comply with 49 CFR § 236.803, i.e., its aspects must convey 
236-80 

advance information about the indication of the home signal it is in approach to. This requires 

that operative approach signals be capable of displaying aspects less restrictive than, “approach 

next signal prepared to stop,” when the home signal displays an aspect indicating more 

permissive than stop or restricting (i.e., warranting a more permissive indication than approach at 

the approach signal). 

An approach signal capable of displaying a single aspect, yellow or lunar, is an inoperative 

signal. 

An approach signal capable of displaying two aspects, red and yellow, is an inoperative signal in 

the application of this rule. It cannot furnish advance information about the indication of the 

home signal when the home signal displays an aspect indicating proceed. 

An approach signal in nonsignaled territory capable of displaying two aspects, yellow and green, 

is an operative signal. 

An approach signal capable of displaying three aspects, red, yellow, and green, is an operative 

signal. 

CLASSIFICATION OF DEFECTS

236.310.A1 Approach signal not provided for home signal on main track. (Does not apply 

where home signal is the first signal encountered when leaving yard or station 

where authorized speed approaching such signal is not higher than slow speed). 

236.310.A2 Inoperative approach signal provided for home signal where authorized speed 

between home signals on the route governed is greater than 20 mph. 

§ 236.311 Signal control circuits, selection through track relays or devices functioning as 

track relays and through signal mechanism contacts and time releases at automatic 

interlocking. 

 (a) The control circuits for aspects with indications more favorable than “proceed at 

restricted speed” shall be selected through track relays, or through devices that function as track 

relays, for all track circuits in the route governed. 

 (b) At automatic interlocking, signal control circuits shall be selected (1) through track 

relays, or devices that function as track relays, for all track circuits in the route governed and in 

all conflicting routes within the interlocking; (2) through signal mechanism contacts or relay 

contacts closed when signals for such conflicting routes display “stop” aspects; and (3) through 

normal contacts of time releases, time element relays, or timing devices for such conflicting 

routes, or contacts of relays repeating the normal position or normal state of such time releases, 

time element relays, or timing devices.

Application: 

This rule requires that at all interlockings, the control circuit for aspects with indications more 

favorable than “Proceed at Restricted Speed,” be selected through relays or devices that function 

as track relays of all track circuits in the route governed, or through repeating relays for such 

track circuits. Additionally, at automatic interlocking, such control circuits shall be selected 

through relays, or devices that function as track relays, of track circuits in all conflicting routes, 
236-81 

or through repeating relays for such track circuits; through signal mechanism contacts, or 

through relay contacts closed when conflicting signals display stop aspects; and through normal 

contacts of time releases or timing devices for conflicting routes or contact of relays repeating 

the normal position of contacts on such time releases or timing devices. 

This rule applies to both interlocking and traffic control systems. 

This rule does not require control circuits at manual or remote controlled interlockings or 

controlled points be selected through track relays or devices that function as track relays on 

conflicting routes, nor through contacts of signal mechanisms, or relay contacts closed when 

such signals display “Stop” for conflicting routes, nor through “check contacts” closed when 

timing relays, releases, or devices are in their normal state. 

This rule does not apply to control circuits of signals displaying aspects with indications of 

“Proceed at Restricted Speed” except at automatic interlockings. 

CLASSIFICATION OF DEFECTS

236.311.A1 Control circuit for aspect with indication more favorable than “proceed at 

restricted speed” 

not selected through track relays, or devices that function as track relays, for all 

track circuits in the route governed, or through repeating relays for such track 

circuits. 

236.311.B1 Signal control circuit at automatic interlocking not selected through track relays, 

or devices that function as track relays, for all track circuits in the route governed, 

or through repeating relays for such track circuits. 

236.311.B2 Signal control circuit at automatic interlocking not selected through track relays, 

or devices that function as track relays, for all track circuits in all conflicting 

routes within interlocking limits, or through repeating relays for such track 

circuits. 

236.311.B3 Signal control circuit at automatic interlocking not selected through signal 

mechanism contacts for signals on all conflicting routes, or through relay contacts 

closed when such signals display stop aspects. 

236.311.B4 Signal control circuit at automatic interlocking not selected through normal 

contacts of time releases, time element relays, or timing devices for all conflicting 

routes, or through contacts of relays repeating the normal position or normal state 

of such time releases, time element relays, or timing devices. 

§ 236.312 Movable bridge, interlocking of signal appliances with bridge devices.

 When movable bridge is protected by interlocking the signal appliances shall be so 

interlocked with bridge devices that before a signal governing movements over the bridge can 

display an aspect to proceed the bridge must be locked and the track aligned, with the bridge 

locking members within one inch of their proper positions and with the track rail on the movable 

span within three-eighths inch of correct surface and alignment with rail seating device on bridge 
236-82 

abutment or fixed span. Emergency bypass switches and devices shall be locked or sealed.

Application: 

This rule requires that interlocking of movable bridge be so interconnected with bridge devices 

that the bridge must be properly locked and track properly aligned before a signal governing 

movements over the bridge can display an aspect to proceed. 

There are three types of movable spans, bascule, lift, and swing. Regardless of the type of 

bridge, the sequence of operation for rail traffic is as follows: 

1. The bridge must be seated, then locked. 

2. The movable rails must be determined to be in proper surface and alignment with the 

rails on the abutment or fixed span. 

3. Derails, if any, must be placed in non-derailing position. 

4. Interlocked signal may then be operated to display proceed aspect. For water traffic the 

sequence of operation is precisely the opposite. 

Bascule and lift spans require bridge locking devices that can drive locking members between 

the movable span and abutment or fixed span only when the bridge is properly seated. Locking 

devices are required on both ends of lift spans. Only the lift end of bascule spans must be 

locked. When the locking members are within 1 inch of being fully driven, the bridge is 

considered to be properly locked. Bridge locks are not designed to hold the movable span down, 

but rather to determine that the bridge is properly seated. The movable rails of bascule and lift 

bridges often correctly align before the bridge seats, hence the need of bridge locks. 

Swing spans are properly seated when the wedges are driven to lift the span off the center pier. 

Consider swing spans locked when the wedges are within 1 inch of being fully driven. The 

latches of swing spans are not bridge locking members but are provided to stop swing bridges in 

proper alignment as it is being closed. 

Rails which slide or lower to butt with those of the abutment or fixed span, or risers that slide 

into position in the movable joint, must be locked in proper alignment. 

Conley frogs are designed to be self-aligning and are not required to be locked or electrically 

checked for alignment. They are required to be checked for surface. 

All movable joints are required to be locked or electrically determined to be in proper surface 

except for those on the hinged end of bascule bridges. If surface is checked electrically, closely 

inspect plungers and mechanical connections for binding. 

Movable joints are “soft” joints. The three-eighths inch requirement of this rule was not revised 

by the Track Safety Standards and movable joints are not required to be maintained to meet these 

standards. 

At automatic and remote-controlled movable bridge interlockings, those devices used to detect 

and govern movement of water traffic such as audible devices, signal aspects, and electric eyes 
236-83 

are considered interlocking appliances and must operate in their proper sequence and perform 

their intended function. 

All the rules of Subpart C are applicable to interlocked drawbridges. 

Test of bridge locking is determined by withdrawing the locking member or wedge more than 1 

inch and determining whether or not control circuits are opened. 

Test of movable rails for alignment is made by measuring the difference in aligned rails. 

Slide and lift rails should also be tested by manually applying lateral force to the movable rails. 

Test of movable rails for surface should be made by placing an obstruction of more than threeeighths inch (e.g., one-half inch gage) on each rail seat and determining whether the rail can be 

locked or, if electrically checked, whether the circuit controller contacts are opened. 

The RS&I does not define bridge locking, therefore, it is permissible for the carrier to use any 

type of bridge locking desired. The only requirement for the bridge lock is that the movable span 

must be locked with the fixed span. 

Where an emergency release is provided at bridge locking, it is required to be kept locked or 

sealed to prevent the emergency release from being used for routine day-to-day operation. 

Operation of the emergency release shall not defeat the time or approach locking circuits. (See 

Technical Bulletin S-05-01)

CLASSIFICATION OF DEFECTS

236.312.A1 Signal appliances at movable bridge protected by interlocking not so interlocked 

with bridge devices that before a signal governing movements over the bridge can 

display an aspect to proceed, the bridge must be locked and the track properly 

aligned. 

236.312.A2 Signal governing movements over movable bridge protected by interlocking can 

display aspect to proceed with bridge locking member displaced more than one 

inch from its proper position. 

236.312.A3 Signal governing movements over movable bridge protected by interlocking can 

display aspect to proceed with the track rail on the movable span more than threeeighths inch from correct surface with the rail seating device on the bridge 

abutment or fixed span. 

236.312.A4 Signal governing movements over movable bridge protected by interlocking can 

display aspect to proceed with the track rail on the movable span more than threeeighths inch from correct alignment with the rail seating device on the bridge 

abutment or fixed span. 

236.312A5 Emergency bypass switch or device not locked or sealed. 

236.312A6 Operation of the emergency release defeats the time or approach locking circuits. 
236-84 

§ 236.314 Electric lock for hand-operated switch or derail.

 Electric lock shall be provided for each hand-operated switch or derail within interlocking 

limits, except where train movements are made at not exceeding 20 miles per hour. At manually 

operated interlocking it shall be controlled by operator of the machine and shall be unlocked only 

after signals governing movements over such switch or derail display aspects indicating stop. 

Approach or time locking shall be provided.

Application: 

This rule requires each hand-operated switch or derail within interlocking limits, where train 

speeds exceed 20 mph, be electrically locked. At manually operated interlocking, it shall be 

controlled by the operator of the machine. Approach or time locking shall be provided. 

This rule applies to interlockings only. It applies to all hand-operated switches and derails in 

interlocking limits where speeds exceed 20 mph. 

This rule applies to each electric lock applied to a hand-operated switch or derail installed under 

provisions of § 236.301, regardless of speed. 

Approach or time locking must be provided for each electrically locked switch or derail 

regardless of speed. 

CLASSIFICATION OF DEFECTS

236.314.A1 Electric lock not provided for hand-operated switch or derail within interlocking 

limits. (Does not apply where train movements are made at speeds not exceeding 

20 mph.) 

236.314.A2 Electric lock on hand-operated switch or derail at manually operated interlocking 

not controlled by operator of the machine. 

236.314.A3 Electric lock on hand-operated switch or derail within interlocking limits can be 

 unlocked before signals governing movements over such switch or derail display 

 aspects indicating stop. 

236.314.A4 Approach or time locking not provided for electric lock on hand-operated switch 

or derail within interlocking limits. 

236.314.A5 Electric lock on hand-operated switch or derail within interlocking limits can be 

unlocked before the expiration of the predetermined time interval, where time 

locking is provided. 

236.314.A6 Electric lock on hand-operated switch or derail within interlocking limits can be 

unlocked before the expiration of the predetermined time interval, with approach 

section occupied, where approach locking is provided. 

236.314.A7 Approach or time locking of electric lock at hand-operated switch or derail can be 

defeated by the unauthorized use of emergency device which is not kept sealed in 

the non-release position. 
236-85 

236.314.A8 Approach locking not effective. 

236.314.A9 Time locking not effective. 

Rules and Instructions

§ 236.326 Mechanical locking removed or disarranged; requirements for permitting train 

 movements through interlocking. 

 When mechanical locking of interlocking machine is being changed or is removed from the 

machine, or locking becomes disarranged or broken, unless protection equivalent to mechanical 

locking is provided by electric locking or electric circuits, train movements through the 

interlocking shall not be permitted until each switch, movable-point frog, or derail in the route is 

spiked, clamped, or blocked in proper position so that it cannot be moved by its controlling lever, 

and then train movements shall not exceed restricted speed until the interlocking is restored to 

normal operation. It will not be necessary to comply with this requirement at interlockings 

where protection is in service in accordance with section 303, provided that the signal controls 

are arranged so that the signals cannot display an aspect the indication of which is less restrictive 

than “proceed at restricted speed.”

Application: 

This rule prescribes the procedures for train operation through interlocking when the mechanical 

interlocking is being changed or is removed from the machine, or locking becomes disarranged 

or broken. 

The procedures prescribed by this rule apply when mechanical locking is being modified, is 

broken and during repairs, becomes disarranged and is inoperable or uncertain in its operation, is 

being replaced by electric circuits, and on those occasions when the interlocking is destroyed or 

heavily damaged by such as fire, derailment, or storm. 

When mechanical locking is inoperable, equivalent protection may be provided by electric 

locking or electric circuits. If such equivalent protection is not provided, each switch, movablepoint frog, or derail in the route must be spiked, clamped, or blocked in proper position before 

train movement is permitted, such movement not to exceed restricted speed. It is not necessary 

to spike, clamp, or block each switch, movable-point frog, or derail if protection is provided in 

accordance with § 236.303 and control circuits are arranged to prevent display of aspects which 

indicate more favorable than “Proceed at Restricted Speed.” 

CLASSIFICATION OF DEFECTS

236.326.A1 Train movement permitted through interlocking while mechanical locking of 

interlocking machine is being changed or is removed, or when locking is 

disarranged or broken, without each switch, movable-point frog, and derail in 

route over which movement is made being spiked, clamped, or blocked so that it 

cannot be moved by its controlling lever. (Does not apply if protection equivalent 

to mechanical locking is provided by electric locking or electric circuits, or where 

protection is in service in accordance with § 236.303 for all signal aspects, and 
236-86 

signal controls are arranged so that the signals cannot display an aspect the 

indication of which is less restrictive than "Proceed at restricted speed.") 

236.326.A2 Train movement exceeds restricted speed through interlocking while mechanical 

locking of interlocking machine is being changed, is removed from the machine, 

or is disarranged or broken. 

§ 236.327 Switch, movable-point frog, or split-point derail.

 Switch, movable-point frog, or split-point derail equipped with lock rod shall be maintained 

so that it can not be locked when the point is open three-eighths inch or more.

Application: 

This rule requires that lock rod of switch, movable-point frog, or split-point derail be so adjusted 

that locking is prevented when the switch point is obstructed by three-eighths inch or more 

obstruction. 

This rule applies to both interlocking and traffic control systems. 

Applies to power-operated or mechanically operated switches, movable-point frogs, and splitpoint derails. 

Test should be made by placing three-eighths inch obstruction between the switch point and 

stock rail, about 6 inches from the end of the point, and then operating switch until the locking 

dog on the slide bar strikes the lock rod. 

Test may be made either under power or by operation of the hand operation lever or crank where 

such machine is designed to lock up in hand operation. Inspector should be alert for instances 

where excessive switch point pressure prevents the locking dog from moving far enough to strike 

the lock rod. Until that action is verified, the test is not performed. 

CLASSIFICATION OF DEFECTS

236.327.A1 Switch, movable-point frog, or split-point derail can be locked when switch point 

is open three-eighths inch or more. 

§ 236.328 Plunger of facing-point lock.

 Plunger of lever operated facing-point lock shall have at least 8-inch stroke. When lock lever 

is in unlocked position, the end of the plunger shall clear the lock rod not more than 1 inch.

Application: 

This rule requires that plunger of lever operated facing-point lock have at least an 8-inch stroke 

and, when unlocked, clear the lock rod not more than 1 inch. This rule applies to both 

interlocking and traffic control systems. 

This rule applies only to independently operated mechanical pipe-connected facing-point lock. 
236-87 

This rule does not apply to hand-operated switch machines or mechanically operated switch-andlock movements. 

CLASSIFICATION OF DEFECTS

236.328.A1 Stroke of plunger of facing-point lock less than 8 inches. 

236.328.A2 End of lock plunger clears lock rod more than 1 inch when lock lever is in 

unlocked position. 

§ 236.329 Bolt Lock.

 Bolt lock shall be so maintained that signal governing movements over switch or derail and 

displaying an aspect indicating stop cannot be operated to display a less restrictive aspect while 

derail is in derailing position, or when switch point is open one-half inch or more.

Application: 

This rule requires that bolt lock be so maintained that signal governing movement over a switch 

or derail cannot display any aspect to proceed unless derail is in non-derailing position and 

switch is within one-half inch of its proper position. 

This rule applies to mechanically operated signal governing movements over switch or derail 

equipped with bolt lock. 

CLASSIFICATION OF DEFECTS

236.329.A1 Bolt lock does not prevent signal from being operated to display an aspect less 

restrictive than “Stop” while derail is in derailing position. 

236.329.A2 Bolt lock does not prevent signal from being operated to display an aspect less 

restrictive than “Stop” when switch point is open one-half inch or more. 

§ 236.330 Locking dog of switch-and-lock movement.

 Locking dog of switch-and-lock movement shall extend through lock rod one-half inch or 

more in either normal or reverse position.

Application: 

This rule requires that locking dog of switch-and-lock movement extend through lock rod onehalf inch or more when locked in either normal or reverse position. 

This rule applies to both interlocking and traffic control systems. 

This rule applies only to pipe-connected, mechanically operated switch-and-lock movements. It 

does not apply to power-operated switch machines such as US&S M2, M3, M22, or M23 

machines; or GRS Model 5 or 55 switch machines. 
236-88 

Holes and notches in lock rod should have square edges to prevent forcing locking dog or 

plunger into lock rod. Section 236.11 may be cited in instances where the edges are excessively 

shaven or rounded. (See Technical Bulletin S-96-01)

CLASSIFICATION OF DEFECTS

236.330.A1 Locking dog of switch-and-lock movement extends through lock rod less than 

one-half inch in normal or reverse position. 

§ 236.334 Point detector.

 Point detector shall be maintained so that when switch mechanism is locked in normal or 

reverse position, contacts cannot be opened by manually applying force at the closed switch 

point. Point detector circuit controller shall be maintained so that the contacts will not assume 

the position corresponding to switch point closure if the switch point is prevented by an 

obstruction, from closing to within one-fourth inch where latch-out device is not used, and to 

within three-eighths inch where latch-out device is used.

Application: 

This rule requires that point detector be so maintained that contacts cannot be opened by 

manually applying force at the closed point when switch is locked in either normal or reverse 

position. Its circuit controller contacts shall not assume the position corresponding to switch 

point closure if the switch point is prevented, by an obstruction, from closing to within onefourth inch where latch-out device is not used, and three-eighths inch where latch-out device is 

used. 

This rule applies to power-operated switches only in both interlocking and traffic control 

systems. 

Tests for compliance should be made in the same manner as switch obstruction tests described 

under § 236.327, by placing an appropriate gauge between the stock rail and switch point, about 

6 inches from the end of the switch point, and closing the switch point on the gauge. The switch 

must be caused to lock up so that the contacts are known to be opened by the point detection 

function with the switch point gapping rather than by an incomplete movement of the locking 

mechanism. 

Where carriers maintain lock rods to obstruct on a one-fourth inch obstruction, it may be 

necessary to either loosen the lock rod, or simulate movement of the point by displacement of the 

point detector rod in order to test the point detector contact adjustment. 

Lateral force should be applied to the closed switch point to determine if contacts can be opened 

because of excessive size of notch in lock rod, loose lock rod connections, or improper point 

detector rod adjustment. 

The inspector should determine the latch-out device is properly adjusted and functioning within 

prescribed limits. If latch-out is not connected or functioning properly, point detector adjustment 

must comply with one-fourth inch requirements. Section 236.11 may be cited in instances where 

a latch-out is provided; however, it does not hold open the circuit controller contacts when 

latched out. 
236-89 

CLASSIFICATION OF DEFECTS

236.334.A1 Point detector contacts can be opened by manually applying force at the closed 

switch point when switch mechanism is locked in normal or reverse position. 

236.334.A2 Point detector circuit controller contacts assume the position corresponding to 

switch point closure when switch point is prevented by an obstruction from 

closing to within one-fourth inch. (Applies only to point detector where latch-out 

device is not used or is not effective.) 

236.334.A3 Point detector circuit controller contacts assume position corresponding to switch 

point closure when switch point is prevented by an obstruction from closing to 

within three-eighths inch. (Applies only to point detector where a latch-out 

device is used and is effective.) 

§ 236.335 Dogs, stops, and trunnions of mechanical locking.

 Driving pieces, dogs, stops, and trunnions shall be rigidly secured to locking bars. Swing 

dogs shall have full and free movement. Top plates shall be maintained securely in place.

Application: 

This rule requires that driving pieces, dogs, stops, and trunnions be rigidly fastened to locking 

bars; that swing dogs have full and free movement; and that top plates be securely fastened in 

place. 

This rule applies to mechanical locking beds only. It does not apply to locking of switch 

machines. 

Mechanical locking cabinets should be opened to fully expose locking and a close inspection 

should be made to ensure compliance. 

The floor of and around interlocking machine cabinets should be closely observed for parts that 

have fallen from locking; and for parts such as screws, rivets, shavings, chips, and other evidence 

of poor maintenance or abuse of locking. 

 

CLASSIFICATION OF DEFECTS

236.335.A1 Driving piece not rigidly secured to locking bar. 

236.335.A2 Dog not rigidly secured to locking bar. 

236.335.A3 Stop not rigidly secured to locking bar. 

236.335.A4 Trunnion not rigidly secured to locking bar. 

236.335.A5 Swing dog does not have full or free movement. 

236.335.A6 Top plate not secured in place. 
236-90 

§ 236.336 Locking bed.

 The various parts of the locking bed, locking bed supports, and tappet stop rail shall be 

rigidly secured in place and aligned to permit free operation of locking.

Application: 

This rule requires that various parts of the locking bed, locking bed supports, and tappet stop rail 

be rigidly secured in place and aligned to permit free operation of locking. 

Locking bed must be securely fastened in place for proper operation. 

CLASSIFICATION OF DEFECTS

236.336.A1 Locking bed parts, supports, or tappet stop rail not rigidly secured in place. 

236.336.A2 Locking bed parts, supports, or tappet stop rail not aligned to permit free 

operation of locking. 

§ 236.337 Locking faces of mechanical locking; fit.

 Locking faces shall fit squarely against each other with a minimum engagement when locked 

of at least one-half the designed locking face.

Application: 

This rule requires locking faces fit squarely against each other when locked with minimum 

engagement of at least one-half the designed locking face. 

Apply this rule to broken or badly worn locking pieces, dogs, tappets, and cross-locking. 

Some cross-locking may require removal of cover plates for inspection. 

CLASSIFICATION OF DEFECTS

236.337.A1 Locking faces do not fit squarely against each other. 

236.337.A2 Locking faces fit with a minimum engagement when locked of less than one-half 

the designed locking face. 

§ 236.338 Mechanical locking required in accordance with locking sheet and dog chart.

 Mechanical locking shall be in accordance with locking sheet and dog chart currently in 

effect.

Application: 

This rule requires that mechanical locking in service shall be in accordance with locking sheet 

and dog chart. 
236-91 

Section 236.1 requires locking sheet and dog chart to be kept at mechanical interlocking and to 

be correct and legible. Locking should be carefully examined to determine compliance with 

locking sheet and dog chart. 

Most mechanical locking, being old, has been altered. Locking that is no longer in service is not 

required to be removed from locking bed and not required to be shown on locking sheet and dog 

chart. 

CLASSIFICATION OF DEFECTS

236.338.A1 Mechanical locking not in accordance with locking sheet and dog chart currently 

in effect. 

§ 236.339 Mechanical locking; maintenance requirements. 

 Locking and connections shall be maintained so that, when a lever or latch is mechanically 

locked the following will be prevented: 

 (a) Mechanical machine. 

 (1) Latch-operated locking. Raising lever latch block so that bottom thereof is within 

three-eighths inch of top of quadrant. 

 (2) Lever-operated locking. Moving lever latch block more than three-eighths inch on top of 

quadrant. 

 (b) Electro-mechanical machine. 

 (1) Lever moving in horizontal plant. Moving lever more than five-sixteenths inch when in 

normal position or more than nine-sixteenths inch when in reverse position. 

 (2) Lever moving in arc. Moving lever more than 5 degrees. 

 (c) Power machine. 

 (1) Latch-operated locking. Raising lever latch block to that bottom thereof is within seven 

thirty-seconds inch of top of quadrant. 

 (2) Lever moving in horizontal plane. Moving lever more than five-sixteenths inch when in 

normal position or more than nine-sixteenths inch when in reverse position. 

 (3) Lever moving in arc. Moving lever more than 5 degrees.

Application: 

This rule requires that locking and connections be maintained so that motion of levers or latches, 

when locked, do not exceed prescribed tolerances. 

Mechanical Machine: 

When this rule was first adopted, more than 90 percent of mechanical interlocking machines 

installed were of two types: Saxby and Farmer (S&F) and Style A. Both have latch-operated 

locking. They are easily recognizable in that S&F machines have rocker arms that stand above 

the quadrants and Style A machines have rocker arms that stand below the quadrants. Other 

latch-operated machines are dwarf S&F, Johnson, and National. 

When locked, the latch block of each lever may not be raised so that the bottom is within threeeighths inch of top of quadrant. 
236-92 

The balance of the machines installed have lever-operated locking. The majority of these were 

Style C and Stevens, which are almost identical, and dwarf machines other than S&F. These 

machines are easily recognizable by the absence of rocker arms. 

When locked, the lever latch block may not be moved more than the three-eighths inch on top of 

the quadrant. 

Electro-Mechanical Machine: 

Electro-mechanical machines are combinations of electric machines and mechanical machines. 

The electric machine levers are located above the mechanical levers and are usually Model 14, 

Model 2, Model 5 or Style S-8 type machines, which control electrical circuits and operate 

miniature type locking to release or lock the mechanical levers. 

When locked, electric levers operating in horizontal plane may not be moved more than fivesixteenths inch in normal position or more than nine-sixteenths inch in reverse position. 

When locked, electric levers moving in an arc may not be moved more than 5 degrees. 

When locked, the mechanical levers must comply with requirements for mechanical machines. 

Power Machine: 

At some large manual interlockings, power (electric) interlocking machines manufactured by the 

Federal Railway Signal Company were installed. These machines are a miniature Type S&F 

mechanical machine with dwarf type of S&F locking with latch locking. When locked, the latch 

block of each lever may not be raised so that the bottom thereof is within seven thirty-seconds 

inch of top of quadrant. 

The majority of power interlocking machines installed at large manual interlockings were Model 

2, Model 14, and Model 5. At small interlockings, Style TC and Type A table interlocking 

machines are frequently found. Model 2 and Model 5 machines have levers that move in a 

horizontal plane. The levers of these machines must meet the same requirements as the electric 

levers of electro-mechanical machines. 

CLASSIFICATION OF DEFECTS

236.339.A1 Lever latch block can be raised so that its bottom is within three-eighths inch of 

top of quadrant when latch is mechanically locked. (Applies only to mechanical 

interlocking machine with latch-operated locking.) 

236.339.A2 Lever latch block can be moved more than three-eighths inch on top of quadrant 

when lever is mechanically locked. (Applies only to mechanical interlocking 

machine with lever-operated locking.) 

236.339.B1 Lever which is mechanically locked in normal position can be moved more than 

five-sixteenths inch. (Applies only to electromechanical interlocking machine 

with levers moving in a horizontal plane.) 

236.339.B2 Lever which is mechanically locked in reverse position can be moved more than 
236-93 

nine-sixteenths inch. (Applies only to electro-mechanical interlocking machine 

with levers moving in a horizontal plane.) 

236.339.B3 Lever which is mechanically locked can be moved more than 5 degrees. (Applies 

only to electromechanical machine with levers moving in an arc.) 

236.339.C1 Lever latch block can be raised so that its bottom is within seven thirty-seconds 

inch of top of quadrant, when latch is mechanically locked. (Applies only to 

power interlocking machine with latch-operated locking.) 

236.339.C2 Lever which is mechanically locked in normal position can be moved more than 

five-sixteenths inch. (Applies only to power interlocking machine with levers 

moving in a horizontal plane.) 

236.339.C3 Lever which is mechanically locked in reverse position can be moved more than 

nine-sixteenths inch. (Applies only to power interlocking machine with levers 

moving in a horizontal plane.) 

236.339.C4 Lever which is mechanically locked can be moved more than 5 degrees. (Applies 

only to power interlocking machines with levers moving in an arc.) 

§ 236.340 Electro-mechanical interlocking machine; locking between electrical and 

mechanical 

 levers.

 In electro-mechanical interlocking machine, locking between electric and mechanical levers 

shall be maintained so that mechanical lever cannot be operated except when released by electric 

lever.

Application: 

This rule requires that locking between electric and mechanical levers of electro-mechanical 

interlocking machine be maintained so that mechanical lever cannot be operated except when 

released by an electric lever. 

The mechanical levers that operate switches, movable-point frogs, and derails must be locked by 

the electric levers. 

CLASSIFICATION OF DEFECTS

236.340.A1 Locking between electric and mechanical levers of electro-mechanical 

interlocking machine not effective to prevent operation of mechanical lever 

without being released by electric lever. 

§ 236.341 Latch shoes, rocker, links, and quadrants.

 Latch shoes, rocker links, and quadrants of Saxby and Farmer machines shall be maintained 

so that locking will not release if a downward force not exceeding a man’s weight is exerted on 

the rocker while the lever is in the mid-stroke position.
236-94 

Application: 

This rule requires that latch shoes, rocker links, and quadrants of Saxby and Farmer machines be 

maintained so that locking will not release when a downward force not exceeding a man's weight 

is exerted on the rocker with the lever in mid-stroke position. 

Care should be exercised when making this test. Rocker arms are cast metal and can easily be 

broken with lever in mid-stroke position. A cracked rocker arm or worn linkage will release the 

locking. If locking is worn, very little pressure is needed to ascertain a failure to meet the 

requirements. 

CLASSIFICATION OF DEFECTS

236.341.A1 Mechanical locking of Saxby and Farmer interlocking machine releases when a 

downward force not exceeding a man’s weight is exerted on rocker while lever is 

in mid-stroke position.

§ 236.342 Switch circuit controller.

 Switch circuit controller connected at the point to switch, derail, or movable-point frog, shall 

be maintained so that its contacts will not be in position corresponding to switch point closure 

when switch point is open one-fourth inch or more.

Application: 

This rule requires that switch circuit controller connected at the point to switch, derail, or 

movable-point frog be maintained so that its contacts will not be in position corresponding to 

switch point closure when point is open one-fourth inch or more in either normal or reverse 

position. 

This rule applies to both interlocking and traffic control systems. 

Apply this rule where switch circuit controller is connected to spring switch, to pipe-connected 

switch, derail, or movable-point frog, and where external circuit controller is added to poweroperated switch or to spring switch. 

CLASSIFICATION OF DEFECT

236.342.A1 Contacts of switch circuit controller connected at the point to switch, derail, or 

movable-point frog are in position corresponding to switch point closure when 

switch point is open one-fourth inch or more. 

Inspections and Tests

§ 236.376 Mechanical locking.

 Mechanical locking in interlocking machine shall be tested when new locking is installed; 

and thereafter when change in locking is made, or locking becomes disarranged, or tested at least 
236-95 

once every 2 years, whichever shall occur first.

Application: 

This rule requires testing of mechanical locking when new locking is installed, when there is a 

change in locking, or when locking is restored after being disarranged. It requires a complete 

test of all mechanical locking at least once every 2 years. (See Technical Bulletin S-04-01). 

Mechanical locking tests should be made by establishing a route and trying all conflicting signal 

control levers before pulling the signal lever. The signal lever should then be pulled. This 

should lock out all opposing and conflicting route lineups and prevent the movement of any lever 

controlling any switch, movable-point frog, or derail in the route lined up. 

On levers equipped with electric locks, the lock should be deenergized and the latch rattled and 

moved around to see that it is mechanically impossible to release the lock. 

Test should be made to ensure that levers equipped with electric locks mechanically lock all 

levers previously operated in that lineup. 

Check shall be made to determine that the locking is in accordance with the locking sheet and 

dog chart as required by § 236.338. 

Test should not be made when the route has been cleared for a rail movement or if rail traffic is 

within the route or a conflicting route. 

Compliance with §§ 236.326, 236.335, 236.336, 236.337, 236.338, 236.339, 236.340, and 

236.341 is required. 

CLASSIFICATION OF DEFECTS

236.376.A1 Mechanical locking of interlocking machine not tested when new locking is 

placed in service. 

236.376.A2 Mechanical locking not tested when change in locking is made. 

236.376.A3 Mechanical locking not tested when restored after being disarranged. 

236.376.A4 Complete test of mechanical locking in interlocking machine not made at least 

once every 2 years. 

§ 236.377 Approach locking.

 Approach locking shall be tested when placed in service and thereafter when modified, 

disarranged, or at least once every 2 years, whichever shall occur first.

Application: 

This rule requires that approach locking be tested when installed, modified, or disarranged, and 

at least once every 2 years thereafter. (See Technical Bulletin S-04-01)
236-96 

This rule applies to both interlocking and traffic control systems. It applies to approach locking 

of both power-operated devices and electrically locked, hand-operated switches in both 

interlockings and traffic control systems. 

Tests shall not be made if any route has been cleared for rail movement or if rail movement is 

within route to be tested or conflicting route. 

Manual interlocking and controlled point: 

Each track section within the limits of the approach circuit shall be shunted and inspection made 

to determine that the approach relay is deenergized by each shunt. 

Signal shall than be cleared by regular operation and shunt placed in approach section or 

approach relay deenergized. Signal shall then be restored to its stop indication and inspection 

made to determine that timing relay or timing device, if provided, is energized. Each switch, 

movable-point frog, derail, or electrically locked switch in route governed shall be tried to ensure 

their positions cannot be changed, or a conflicting signal be cleared, during the predetermined 

time interval. 

Where time release must be operated, each switch, movable-point frog, or derail must be tried to 

ensure their positions cannot be changed, or a conflicting signal be cleared, both prior to 

operation of time release and after its operation during its predetermined time interval. 

Test each route governed by each signal. 

Automatic interlockings: 

Each track section within the limits of the approach circuit shall be shunted and inspection made 

to determine that the approach relay is deenergized by each shunt. 

Clear home signal by placing a shunt in the approach section or by opening the approach circuit. 

Next, place a shunt in the approach section or open the approach circuit of a conflicting route. 

Then, operate the time release or pushbutton for the conflicting route, and determine that the 

home signal is immediately restored to its stop position and that the conflicting route is not 

established until the prescribed time interval has expired. 

Some interlockings have superior routes that, when the approach section is occupied, cause any 

cleared signals governing conflicting routes to display stop indications and timing relay or timing 

device to operate, and after the expiration of the predetermined time interval, clears the signal 

governing the superior route. Some automatic interlockings have inferior routes that, when the 

approach section is occupied and home signal cleared, timing relay or timing device begins 

operating, and after the expiration of a predetermined time interval, restores the home signal to 

its stop indication. Regardless of the arrangement, changeover shall not occur until after the 

expiration of the prescribed predetermined time interval. 

Hand-operated, electrically locked switches: 

Signal shall be cleared for movement over the switch and a shunt placed on an approach section 

of the approach locking circuit. Then an attempt should be made to unlock the switch. The 
236-97 

locking should 

prevent the unlocking of the switch. Where time is also provided, the switch may be unlocked 

after the expiration of a predetermined time interval. Each approach circuit should be checked 

individually. 

CLASSIFICATION OF DEFECTS

236.377.A1 Approach locking not tested when installed, modified, or after being disarranged. 

236.377.A2 Approach locking not tested at least once every 2 years. 

§ 236.378 Time Locking.

 Time locking shall be tested when placed in service and thereafter when modified, 

disarranged, or at least once every 2 years, whichever shall occur first.

Application: 

This rule requires time locking to be tested when installed, modified, or disarranged, and at least 

once every 2 years thereafter. (See Technical Bulletin S-04-01)

This rule applies to interlocking and traffic control systems. 

This rule applies not only to power-operated devices but also to electrically locked, handoperated switches within interlocking and traffic control systems, where such electric locks are 

provided with time locking. 

Tests should not be made if rail traffic is approaching, or within route to be tested, or within 

conflicting routes. 

Test shall be made by clearing a signal by regular operation. The signal shall then be restored to 

its stop indication, and check made to determine timing relay or timing device, if provided, is 

energized. Each switch, movable-point frog, derail, or electrically locked switch in route 

governed shall be tried to ensure their positions cannot be changed, or a conflicting signal 

established, during the predetermined time interval. 

Where time release must be operated, the above units must be tried, both prior to operation of 

time release and after its operation during its predetermined time interval. 

Test of time locking of electrically locked switch shall be made by clearing a signal governing 

movement over the switch and attempting to unlock the switch. The electric lock on such switch 

should not energize and unlock the switch until a predetermined time interval has expired after 

all signals governing movement over the switch have assumed their most restrictive aspects. 

This test should be made for each signal governing movement over the switch. 

CLASSIFICATION OF DEFECTS

236.378.A1 Time locking not tested when installed, modified, or after being disarranged. 

236.378.A2 Time locking not tested at least once every 2 years. 
236-98 

§ 236.379 Route locking.

 Route locking or other type of switch locking shall be tested when placed in service and 

thereafter when modified, disarranged, or at least once every 2 years, whichever shall occur first.

Application: 

This rule requires that route or any other type of switch locking be tested when installed, 

modified, or disarranged, and at least once every 2 years thereafter. (See Technical Bulletin S04-01)

This rule applies to both interlocking and traffic control systems. 

Tests should not be made if rail traffic is approaching, or within route to be tested, or within 

conflicting routes. 

Test shall be made for all mechanical or power-operated switches and hand-operated, electrically 

locked switches or derails that are locked in both the reverse and normal positions. 

Test shall be made by clearing signal for an established route, after which each track circuit 

within the route shall be progressively shunted beginning with the first track circuit in advance of 

the signal. While each track circuit is shunted, and while assuring time or approach locking is 

restored, each switch, movable-point frog, derail, and facing-point lock lever in the route, shall 

be tried to ensure their positions cannot be changed. 

The rule permits sectional release locking that will release the locking of switches, movablepoint frogs, derails, and facing-point lock levers in the rear of the progressive shunt. Inspection 

shall be made to determine that as each section is released, a route cannot be established that 

would result in improper clearance between train movements. 

Route locking tests shall be conducted over each route governed by each signal and repeated in 

each direction for each route. 

CLASSIFICATION OF DEFECTS 

236.379.A1 Route or other type of switch locking not tested when installed, modified, or after 

being disarranged. 

236.379.A2 Route or other type of switch locking not tested at least once every 2 years. 

§ 236.380 Indication locking.

 Indication locking shall be tested when placed in service and thereafter when modified, 

disarranged, or at least once every 2 years, whichever shall occur first.

Application: 

This rule requires that indication locking be tested when installed, modified, or disarranged, and 

at least once every 2 years thereafter. (See Technical Bulletin S-96-02 and S-04-01)
236-99 

This rule applies to both interlocking and traffic control systems. 

Indication locking for signals. 

Home and approach signals shall be cleared by means of regular operation. Where a separate 

relay repeating only the red and yellow indications of the approach signal is used, visual check 

shall be made to ensure that the clearing of the approach signal causes such relay to become 

deenergized. Where such relay is not used, then a voltmeter shall be connected to the control 

wire for the indication lock at a point between the home and approach signals (line arresters) to 

ensure that the clearing of the approach signal removes energy from such wire. Where two or 

more approach signals are involved, test must be made to ensure that the clearing of each one of 

the approach signals accomplishes this result. 

After this part of the test has been completed, the approach signal shall be set in its restrictive 

position by opening its control circuit. With the home signal clear, a visual check shall be made 

to ensure that the indication lock on the signal lever or lock lever is properly deenergized, or in 

the case of all relay-type locking, that the lock relay is deenergized. 

Next, disconnect a coil wire of the home signal red repeater relay or lock relay, or open the 

control wire of the indication lock where the meter reading was previously taken and restore the 

home signal to stop indication. Visual check shall again be made to ensure that indication lock 

or lock relay is deenergized. 

After above tests are made to ensure that the clearing of either the home or approach signal 

deenergizes the indication lock or lock relay, tests shall be made to ensure that switches, derails, 

and movable-point frogs in the route cannot be changed and that a conflicting signal cannot be 

obtained with the indication lock or lock relay deenergized. 

The test is then completed, where indication lock is used on a lever, by deenergizing the lock by 

opening its control circuit at the coil terminal and clearing the home signal. If the lock is on the 

home signal lever, it shall be tried to ensure it cannot be latched full normal. If the indication 

lock is on a lock lever, the home signal lever shall be placed normal and the lock lever tried to 

ensure that it cannot be unlatched from the reverse position. Where all relay type locking is 

used, open lock circuit at each signal control 

relay or red repeater relay and visually check to ensure the lock relay becomes deenergized. At 

automatic interlocking, proceed as above except check stick locking circuits in lieu of indication 

locking circuits. 

Where signals are of the semaphore type, visual inspection must also be made to ensure that 

locking becomes effective with the signal blade not over 5 degrees above the 45-degree position 

on upper 

quadrant approach signals or 5 degrees below the 45-degree position on lower quadrant approach 

signal, and not over 5 degrees from horizontal on home signals. 

Indication locking for switches: 

Where indication lock is on control lever, with switch in full normal position, the reverse switch 

point shall be obstructed so that the switch cannot operate full throw. The lever shall then be 

operated so that the switch will operate against the obstruction and test made to ensure lever 
236-100 

cannot be latched reverse with the switch unlocked. 

Where all relay type locking is used, the above method of obstruction and switch operation shall 

be followed. A visual check shall be made to ensure indication light on control panel remains 

unlighted, and a trial made to ensure signals governing movements over the switch cannot be 

cleared. 

Above tests shall be made for both the normal and reverse positions of each switch.

CLASSIFICATION OF DEFECTS

236.380.A1 Indication locking not tested when installed, modified, or after being disarranged. 

236.380.A2 Indication locking not tested at least once every 2 years. 

§ 236.381 Traffic locking.

 Traffic locking shall be tested when placed in service and thereafter when modified, 

disarranged, or at least once every 2 years, whichever shall occur first.

Application: 

This rule requires that traffic locking be tested when installed, modified, or disarranged, and at 

least once every 2 years thereafter. (See Technical Bulletin S-04-01)

This rule applies only to interlockings. This testing rule does not apply to traffic control systems. 

Traffic control systems are required to have a similar functionality as prescribed within § 

236.405. However, while it is required as a standard to function properly and as intended, there 

is no requirement to test it within this rule. 

Tests should not be conducted if rail traffic is approaching or within the route to be tested. 

Tests shall be performed by clearing signal governing entrance to the traffic block and checking 

that traffic levers cannot be changed, or opposing signal cleared, until signal is restored to “Stop” 

position and approach or time locking released. Drop each track relay in the traffic block section 

and ensure that traffic lever cannot be moved, direction of traffic changed, or opposing signal 

cleared. 

CLASSIFICATION OF DEFECTS

236.381.A1 Traffic locking not tested when installed, modified, or after being disarranged. 

236.381.A2 Traffic locking not tested at least once every 2 years. 

Excerpt from Mr. Walsh’s letter of January 3, 1985 

To: Mr. L. M. Himmel, Sr. Executive Director 

Operations and Maintenance Department 

Communications and Signals Division 

Association of American Railroads 

 * * * * * 
236-101 

Section 236.376 Mechanical locking. 

Section 236.377 Approach locking. 

Section 236 378 Time locking. 

Section 236.379 Route locking. 

Section 236.380 Indication locking. 

Section 236.381 Traffic locking. 

The AAR requested clarity of the term “disarranged”; questioned whether the removal of two or 

more wires constituted a disarrangement which required the above tests be performed; and 

suggested FRA’s Technical Manual be revised to exempt the requirements of testing where a 

device is provided with plug couplers or the replacement is accomplished by removal of not 

more than one wire at a time. 

These rules prescribe inspection and tests of the various types of locking. The rules require 

mechanical locking be tested when new locking is installed; electric locking be tested when 

placed in service; and all locking be tested thereafter when modified, disarranged, or at least 

once every two years, whichever shall occur first. 

Major sources of false proceed failures for more than five years have been errors in connection 

and errors in design. The revision of these rules resulted in the requirements that tests be 

performed at the time such errors should be detected, before they present hazards to the safety of 

train operation. 

Accordingly, mechanical locking is considered to be disarranged when (i) one or more pieces of 

locking are broken; or (ii) one or more pieces are removed. 

Electric locking is considered to be disarranged when (i) a relay is replaced with another; (ii) 

when two or more signal line wires or a cable having two or more conductors are severed; (III) 

when a cable or conductor in a locking circuit is replaced with another; or (iv) when wires are 

removed at the same time from more than one terminal of a relay or terminal board. 

 * * * * * 

§ 236.382 Switch obstruction test.

 Switch obstruction test of lock rod of each power-operated switch and lock rod of each 

hand-operated switch equipped with switch-and-lock-movement shall be made when lock rod is 

placed in service or changed out, but not less than once each month.

Application: 

This rule requires that a switch obstruction test be made when lock rod is installed and at least 

once a month thereafter. (See Technical Bulletin S-04-01)

This rule applies to interlocking and traffic control systems. 

Tests should not be conducted if rail traffic is approaching or within the route to be tested. 

This rule applies to pipe-connected, mechanically operated switches; electric switches; 

electrohydraulic switches; electropneumatic switches; and hand-operated switch machines with 
236-102 

lock rods, where such hand-operated switch machines are located within interlockings or traffic 

control systems. 

This rule does not apply to hand-operated switches not equipped with switch-and-lock 

movements. 

To test power-operated and mechanical pipe-connected switches for compliance with § 236.327, 

place a 3⁄8-inch obstruction between the switch point and stock rail, 6 inches from the end of the 

switch point, and attempt to lock up the switch. Assurance should be made that the locking dog 

strikes the lock rod. 

To test a hand-operated switch-and-lock movement for compliance with § 236.6, follow the 

same procedure, but use a one-fourth inch obstruction to make the test. 

CLASSIFICATION OF DEFECTS

236.382.A1 Switch obstruction test not made when lock rod installed. 

236.382.A2 Switch obstruction test not made at least once each month.

§ 236.383 Valve locks and valve magnets.

 Valve locks on valves of the non-cut-off type shall be tested at least once every 3 months, 

and valves and valve magnets shall be tested at least once every year.

Application: 

This rule requires that valve locks on valves of the non-cut-off type be tested at least once every 

3 months and valves and valve magnets be tested once every year. (See Technical Bulletin S-04-

01)

This rule applies to interlocking and traffic control systems. 

Tests should not be conducted while rail traffic is approaching or within any route that might be 

affected by the tests. 

Tests shall be conducted by removing valve stem or control wire from lock magnet of electropneumatic switch. Switch should not move. 

Where “CP” valves are used, place switch lever in normal, close globe valve, and remove plug in 

reverse side of switch cylinder. Then move lever to reverse indicating point. Indication should 

not be received when lever is moved to reverse. Restore plug and open globe valve, reverse 

switch, and repeat test. 

Test “D” valve of non-cut-off type in normal and reverse positions by removing armature stem in 

lock valve magnet and operating controlling lever; switch should not respond. 

Test each set of cut-off valves with switch in normal position by holding lock and reverse 

armature in for about 1 minute while normal magnet is energized; switch should not respond. 
236-103 

Repeat in reverse position, holding lock and normal armatures while reverse magnet is 

energized. 

CLASSIFICATION OF DEFECTS

236.383.A1 Valve lock in electro-pneumatic interlocking not tested at least every 3 months. 

(Applies only to valves of the non-cut-off type.) 

236.383.A2 Valve in electro-pneumatic interlocking not tested at least once every year. 

236.383.A3 Valve magnet in electro-pneumatic interlocking not tested at least once every 

year. 

§ 236.384 Cross protection.

 Cross protection shall be tested at least once every 6 months.

Application: 

This rule requires that cross protection be tested at least once every 6 months. (See Technical 

Bulletin 

S-04-01)

This rule applies only to those interlockings provided with cross protection devices. 

Tests should not be conducted while rail traffic is approaching or within the section of 

interlocking to be tested. 

This test ensures that switches, signals, etc., do not respond when current is improperly applied 

to circuits. It is recommended that a variable resistor be used in making the test. 

Tests should be made when plant voltage is at the maximum. 

Make temporary connection between normal and reverse operating wires for each switch at the 

pole changer. This should open polar relay or circuit breaker. 

Make temporary positive battery connection from the nearest switch to the signal control wire as 

close as practicable to the signal motor. This should open the polar relay or circuit breaker. 

If the signal control circuit is connected to the common return wire through one or more switch 

circuit controllers, the energy should be applied to this wire, first opening the connection to the 

main common to prevent blowing fuse in the switch circuit. If plant is sectionalized, one or 

more functions in each section should be crossed with wires taking energy from each of the other 

sections. In the event that functions in various sections are too widely separated, the temporary 

crosses can be made between the binding posts on the terminal board of the interlocking 

machine. This should open the section breakers. 

CLASSIFICATION OF DEFECTS

236.384.A1 Cross protection not tested at least once every 6 months. 
236-104 

§ 236.386 Restoring feature on power switches.

 Restoring feature on power switches shall be tested at least once every 3 months.

Application: 

This rule requires that restoring feature on power switches be tested once every 3 months. (See 

Technical Bulletin S-04-01)

This rule applies to interlocking and traffic control systems. 

This rule applies only to electro-pneumatic switches. Air shall be removed from switch before 

testing. Test shall be made by using a bar and moving slide bar of switch movement toward 

opposite position where locking dog will become disengaged from lock rod. Test to ascertain 

that indication circuits are opened and/or lock magnet circuit is energized before locking dog is 

completely withdrawn from lock rod. Restore air to determine that slide bar is driven back to its 

original position. 

CLASSIFICATION OF DEFECTS

236.386.A1 Restoring feature on power switch not tested at least once every 3 months. 

§ 236.387 Movable bridge locking.

 Movable bridge locking shall be tested at least once a year.

Application: 

This rule requires movable bridge locking to be tested at least once a year. (See Technical 

Bulletin 

S-04-01)

This rule applies to movable bridge interlockings. Test shall be made by displacing bridge 

locking members more than 1 inch from their proper position and determining that signals cannot 

be cleared to authorize movement over the movable bridge. 

When movable bridge is equipped with circuit controllers with or without mechanical rail locks, 

movable rails shall be displaced more than three-eighths inch (e.g., one-half inch gage) from 

their correct surface or alignment with adjacent fixed rail by an obstruction. 

With the movable rail thus displaced, the rail lock should not lock up and if rail lock is not 

provided, signals cannot be cleared to authorize movement over the movable bridge. 

This test should be made for each rail lock or circuit controller on the bridge that checks for 

correct rail alignment or surface. 

Check operation of all circuit controllers connected to the wedges, latches, rail locks, etc., to see 

that contacts make or break when corresponding functions are in their proper position. 
236-105 

CLASSIFICATION OF DEFECTS

236.387.A1 Movable bridge locking not tested at least once a year. 

Subpart D – Traffic Control Systems 

Standards

§ 236.401 Automatic block signal system and interlocking standards applicable to traffic 

control 

 systems.

 The standards prescribed in §§ 236.201 to 236.203, inclusive, §§ 236.205, 236.206, 236.303, 

236.307 and 236.309 to 236.311, inclusive, shall apply to traffic control systems.

Application: 

This rule prescribes the following automatic block signal system and interlocking standards be 

applied to traffic control systems: 

§ 236.201 Track-circuit control of signals. 

§ 236.202 Signal governing movements over hand-operated switch. 

§ 236.203 Hand-operated crossover between main tracks; protection. 

§ 236.205 Signal control circuits; requirements. 

§ 236.206 Battery or power supply with respect to relay; location. 

§ 236.303 Control circuits for signals, selection through circuit controller operated by switch 

points or by switch locking mechanism. 

§ 236.307 Indication locking. 

§ 236.309 Loss of shunt protection; where required. 

§ 236.310 Signal governing approach to home signal. 

§ 236.311 Signal control circuits, selection through track relays, or devices functioning as track 

relays, and through signal mechanism contacts and time releases at automatic interlocking. 

§ 236.402 Signals controlled by track circuits and control operator.

 The control circuits for home signal aspects with indications more favorable than “proceed at 

restricted speed” shall be controlled by track circuits extending through entire block. Also in 

addition, at controlled point they may be controlled by control operator, and, at manually 

operated interlocking, they shall be controlled manually in cooperation with control operator.

Application: 

This standard requires that all home signal aspects with indications more favorable than “proceed 

at restricted speed” be controlled by track circuit extending through the entire block. At a 

controlled point, the control circuits may be controlled by a control operator; and at manually 

operated interlockings, the home signals shall be controlled manually in cooperation with the 

control operator. 
236-106 

Any aspects with indications more favorable than “proceed at restricted speed” must be selected 

through track relays, regardless of any speed limit or restriction. The aspects and indications of 

the governing signals determine compliance with this standard, not the authorized train speed. 

A block extends from a signal to the next governing signal or from a signal to the limits or end of 

the system. The end of the system, absent a signal, may be identified by the use of wayside 

signage, or by specific designation in the carrier’s timetable or special instructions. 

Control circuits do not have to be manually controlled by the operator and may be automatic. 

However, it is not the intention of this rule to give control to any other individual operation in 

opposition to or in conflict with the control operator. 

CLASSIFICATION OF DEFECTS

236.402.A1 Signal control circuits for home signal aspect with indication more favorable than 

“proceed at restricted speed” not controlled by track circuits extending through 

the entire block. 

236.402.A2 Signal at manually operated interlocking not controlled manually in cooperation 

with control operator. 

§ 236.403 Signals at controlled point.

 Signals at controlled point shall be so interconnected that aspects indicating to proceed 

cannot be displayed simultaneously for conflicting movements, except that opposing signals may 

display an aspect indicating “proceed at restricted speed” at the same time on a track used for 

switching movements only, by one train at a time.

Application: 

This rule requires signals at a controlled point to be so interconnected that any aspects indicating 

to proceed cannot be displayed simultaneously for conflicting movements, except that opposing 

signals may display an aspect indicating “proceed at restricted speed” at the same time on track 

used for switching movements only. 

This is a companion rule to § 236.308 in that it permits display of aspect indicating “proceed at 

restricted speed” on opposing signals at the same time on track used for switching movements 

only by one train at a time. 

CLASSIFICATION OF DEFECTS

236.403.A1 Signals at controlled point can simultaneously display aspect indicating to 

proceed for 

 conflicting train movements. (Does not apply to opposing signals on track used 

for switching movements only by one train at a time). 

236.403.A2 Signals at controlled point can simultaneously display aspect indicating more 

favorable than “proceed at restricted speed” for opposing train movements. (Does 

not apply to opposing signals on track used for switching movements only by one 

train at a time). 
236-107 

§ 236.404 Signals at adjacent controlled points.

 Signals at adjacent controlled points shall be so interconnected that aspects indicating to 

proceed on tracks signaled for movements at greater than restricted speed cannot be displayed 

simultaneously for conflicting movements.

Application: 

This rule requires that signals at adjacent controlled points be interconnected so that aspects 

indicating to proceed on tracks signaled for movements at greater than restricted speed cannot be 

displayed simultaneously for conflicting movements. 

This rule permits restricted speed aspects to be displayed simultaneously for opposing or 

converging routes at adjacent control points provided the speed restrictions between the control 

points do not exceed 20 mph. The rule was revised in 1964, primarily to permit restricted speed 

conflicting movements into a siding from each end. The maximum authorized speed between 

adjacent controlled points where signals 

can simultaneously display aspects indicating proceed at restricted speed shall not exceed 20 

mph, regardless of more favorable aspects displayed and regardless of whether track is signaled. 

CLASSIFICATION OF DEFECTS

236.404.A1 Signals at adjacent controlled points not so interconnected that aspects indicating 

to proceed, on tracks signaled for movements at greater than restricted speed, 

cannot be displayed simultaneously for conflicting movements. 

§ 236.405 Track signaled for movements in both directions, change of direction of traffic.

 On track signaled for movements in both directions, occupancy of the track between 

opposing signals at adjacent controlled points shall prevent changing the direction of traffic from 

that which obtained at the time the track became occupied, except that when a train having left 

one controlled point reaches a section of track immediately adjacent to the next controlled point 

at which switching is to be performed, an aspect permitting movement at not exceeding restricted 

speed may be displayed into the occupied block.

Application: 

This rule prevents the changing of the direction of traffic from that which was obtained at the 

time the track was occupied between opposing signals at adjacent controlled points on track 

signaled for movement in both directions except that when a train having left one controlled 

point reaches a section of track immediately adjacent to the next controlled point at which 

switching is to be performed, an aspect permitting movement at not exceeding restricted speed 

may be displayed into the occupied block. 

This rule requires that traffic control systems have nearly the functional equivalent as that of 

“traffic locking” installed and operating properly and as intended. However, there is no 

requirement for testing it as prescribed by § 236.381. 

After a train or engine has passed a signal displaying an aspect permitting it to proceed into and 

through a controlled point, the opposing signals at the adjacent controlled point shall not display 

any aspect with an indication other than “stop,” as long as the section of track between controlled 
236-108 

points is occupied. 

The exception to the traffic locking requirements (§ 236.405) applies only in instances when a 

train is left on the main track while its engine and/or cars move into an adjacent siding or yard 

for switching purposes and must, in returning to its train, reverse its direction for a short 

distance. It is permissible in such instances to permit such movements to be made with a signal 

aspect indicating “Proceed at Restricted Speed” into the occupied block. 

CLASSIFICATION OF DEFECTS

236.405.A1 On track signaled for movements in both directions, occupancy of track between 

opposing signals at adjacent controlled points does not prevent changing the 

direction of traffic from that which obtained at the time the track became 

occupied. (Note: An exception added January 24, 1966, permits display of an 

aspect not less restrictive than that indicating “proceed at restricted speed” by a 

signal to permit a locomotive (with or without cars) to return to a standing portion 

of the train in the immediate approach to a controlled point 

 during switching operations. Where a carrier provides the necessary arrangement 

to permit a locomotive to return to its train, as set forth in the exception, such an 

arrangement when actuated does not constitute a violation of § 236.405 and 

should not be reported as such.) 

§ 236.407 Approach or time locking; where required.

 Approach or time locking shall be provided for all controlled signals where route or direction 

of traffic can be changed.

Application: 

This rule requires that approach or time locking be provided for each controlled signal where 

route or direction of traffic can be changed. 

This rule applies to all controlled signals at controlled points where the route can be changed or 

where direction of traffic can be changed. It applies to all controlled signals at controlled points 

where the route can be changed regardless of the type of switch utilized to change the route. 

Does not apply to so-called “holding signals” between controlled points where the direction of 

traffic cannot be changed. (See Technical Bulletin S-99-04)

CLASSIFICATION OF DEFECTS

236.407.A1 Approach or time locking not provided for controlled signal where route or 

direction of traffic can be changed. 

236.407.A2 Approach locking not effective. 

236.407.A3 Time locking not effective. 
236-109 

§ 236.408 Route locking.

 Route locking shall be provided where switches are power-operated. Route locking shall be 

effective when the first pair of wheels of a locomotive or car passes a point not more than 13 feet 

in advance of the signal governing its movement, measured from the center of the signal mast or, 

if there is no mast, from the center of the signal.

Application: 

This rule specifies where route locking shall be provided and where it shall become effective in 

the route entered. 

At any location in traffic control territory where switches are power-operated, route locking must 

be provided; and it must be effective when the first pair of wheels of a locomotive or car passes a 

point 13 feet in advance of the signal governing its movement. 

The 13 feet shall be measured from the center of the signal mast portion on which it is mounted 

(e.g., from center of tall mast, or of off-set or extension mast) to the effective insulated joint. 

Where the signal is not mounted on a vertical ground mast, the 13 feet shall be measured from 

the center of the signal. This rule does not apply to automatic signals or controlled signals that 

do not have power-operated switches in the route governed. 

Route locking is not required or provided where there is an absence of a power-operated switch, 

movable-point frog, or derail in the route. Route locking is also not required by this rule in an 

instance of a train crew receiving permission to pass a stop signal indication (i.e., occupancy of 

the track circuit(s) alone lock the switch). Where any location is found not having the equivalent 

of route locking in that instance, and it is equipped with one or more dual-controlled poweroperated switches, assurance should be gained that the carrier’s special instructions for handoperation of such a switch provide for the safe movement of trains. (For example, the switch 

may not be restored to power operation until the rear of the train has passed over and beyond it.) 

CLASSIFICATION OF DEFECTS

236.408.A1 Route locking not provided where switches are power-operated. 

236.408.A2 Route locking not effective. 

236.408.A3 Route locking not effective until first pair of wheels of locomotive or car passes a 

point more than 13 feet in advance of the signal governing the movement. 

§ 236.410 Locking, hand-operated switch.

 (a) Each hand-operated switch in main track shall be locked either electrically or 

mechanically in normal position, except: 

 (1) Where train speeds over the switch do not exceed 20 miles per hour; 

 (2) Where trains are not permitted to clear the main track; 

 (3) Where a signal is provided to govern train movements from the auxiliary track to the 

signaled track; or 

 (4) On a signaled siding without intermediate signals where the maximum authorized speed 

on the siding does not exceed 30 miles per hour. 
236-110 

 (b) Approach or time locking shall be provided and locking may be released either 

automatically, or by the control operator, but only after the control circuits of signals governing 

movement in either direction over the switch and which display aspects with indications more 

favorable than "proceed at restricted speed'' have been opened directly or by shunting of track 

circuit. 

(c) Where a signal is used in lieu of electric or mechanical lock to govern movements from 

auxiliary track to signaled track, the signal shall not display an aspect indicating to proceed until 

after the control circuits of signals governing movement on main track in either direction over 

the switch have been opened, and either the approach locking circuits to the switch are 

unoccupied or a predetermined time interval has expired. 

Application: 

This rule requires that a hand-operated switch in main track be locked, either electrically or 

mechanically in normal position, or a signal be provided to govern train movements to the 

signaled track. It exempts those hand-operated switches on main track where train speeds do not 

exceed 20 mph, on signaled sidings without intermediate signals where train speeds do not 

exceed 30 mph, or where trains are not permitted to clear the signaled track. It requires approach 

or time locking, and provides that locking may be released either automatically or by the control 

operator after the control circuits of signals governing movements over the switch have been 

opened directly or by shunting of track circuit. 

Any signaled track in traffic control territory is considered as main track. If speed on main track, 

except signaled sidings, exceeds 20 mph, each hand-operated switch must comply with this 

section. Speed may be controlled only by permanent speed restriction or by signal indication. 

Sidings provided with signal protection and without intermediate signals are signaled sidings. If 

train speed exceeds 30 mph on a signaled siding, each hand-operated switch on such siding must 

comply with this section. 

Hand-operated switches are not required to be electrically or mechanically locked, or to be 

equipped with a signal to govern train movements to the signaled track, where trains are not 

permitted to clear the main track. Trains may enter such switches provided a car is left on the 

main track, the switch is left open, or a derail equipped with switch circuit controller is left in 

non-derailing position. Note: This option may not be available to the railroad where a siding 

track, equipped with a hand-operated switch on either end, spans an intermediate or controlled 

point signal location. The reason it is not available is that even though a train may not clear one 

end (leaving a portion of the train on the main track or leaving the switch thrown reverse), and 

the signal governing movement over the switch at that end will therefore be displaying its most 

restrictive indication, the signal governing movement over the switch at the other end of the 

siding track in which the train is located may not be displaying its most restrictive indication 

(equivalent to the train being “cleared” in that track). 

Approach or time locking must be provided for each lock, must be effective, and must be 

installed in such a manner that it cannot be defeated by any action of train crewmembers (except 

via operation of an emergency release device, if so equipped, and as addressed below). 

Locks may be provided with an emergency release device, which must be kept sealed. An 

emergency release device with broken or missing seals is prohibited (except where such a release 
236-111 

device is equipped with a latch out feature that actuates when the emergency device is operated 

and which opens the signal control circuits until being reset by a signal employee). 

Lock may be released either automatically or by control operator. Control circuits of signals 

governing movements over the switch which display aspects indicating more favorable than 

“proceed at restricted speed” must be opened, or track circuit must be shunted, before locking is 

released. 

Electric or mechanical lock provided with time locking must not release until after expiration of 

a predetermined time interval sufficient to permit a train, having passed the signal governing 

movement over the switch displaying an aspect with an indication more favorable than proceed 

at restricted speed, to pass the switch; or, to permit a train approaching the signal governing 

movement over the switch displaying an aspect indicating “stop” or “stop and proceed,” to stop, 

or where the signal governing movement over the switch displays a “restricting” indication, to 

permit the train to reduce to restricted speed. 

Electric or mechanical lock provided with approach locking must not release when approach 

section is occupied until after expiration of a predetermined time interval sufficient to permit a 

train to stop or to pass the switch, or where signal governing movement over the switch displays 

a “restricting” indication as its most restrictive aspect, the train can reduce its speed to restricted 

speed. If approach section is unoccupied, lock may release immediately after signal control 

circuits are opened. 

Control circuit for electric lock must be so arranged and installed that shunting of turnout will 

not release lock for movement to main track. See § 236.16. 

Locking member of electric or mechanical lock must be so maintained that it cannot be displaced 

from its locked position by quickly operating (jiggling) the lock lever or pedestal. 

Where signal is provided in lieu of a lock to govern train movements to signaled track, an aspect 

permitting a train to proceed shall not be displayed until the control circuits for all signals 

governing movement over the switch on the signaled track are opened, and approach circuits in 

both directions are unoccupied, or a predetermined time interval has expired. 

Where exception (1) is relied upon, it is permissible for trains, after approaching the switch at 

speeds not exceeding 20 mph, to accelerate after the locomotive occupies the switch points. 

The provision of exception (2) does not apply to maintenance-of-way work equipment. Such 

maintenance-of-way equipment as motor cars and track machinery such as tampers, liners, burro 

cranes with or without cars, Sperry test cars, and Speno Rail Grinder equipment, is not 

considered to be a train, and may clear the main track in traffic control system (TCS) territory 

without regard to requirements of this rule. 

A previous footnote to this rule since deleted required that all hand-operated switches in traffic 

control territory be brought into compliance with these provisions on or before December 31, 

1986. 
236-112 

CLASSIFICATION OF DEFECTS

236.410.A1 Hand-operated switch on main track not electrically or mechanically locked in 

normal position where signal is not provided to govern movement to main track 

and train movements are made at speeds in excess of 20 mph and train or engine 

movements may clear the main track. 

236.410.A2 Hand-operated switch on signaled siding not electrically or mechanically locked 

in normal position where signal is not provided to govern movements to signaled 

siding and train movements are made at speeds in excess of 30 mph and train or 

engine movements may clear the signaled siding. 

236.410.B1 Approach or time locking not provided for electric lock on hand-operated switch. 

236.410.B2 Approach or time locking not provided in connection with mechanical lock on 

hand-operated switch. 

236.410.B3 Approach or time locking not provided for signal used in lieu of electric or 

mechanical lock. 

236.410.B4 Electric or mechanical lock on hand-operated switch can be unlocked before 

control circuits of signals governing movements over the switch, which display 

aspects indicating more favorable than “proceed at restricted speed,” have been 

opened directly or track circuit has been shunted. 

236.410.B5 Electric or mechanical lock on hand-operated switch can be unlocked before 

expiration of predetermined time interval, with approach section occupied, where 

approach locking is provided. 

236.410.B6 Electric or mechanical lock on hand-operated switch can be unlocked before 

expiration of predetermined time interval where time locking is provided. 

236.410.B7 Approach or time locking of electric lock at hand-operated switch can be defeated 

by the unauthorized use of emergency release device of electric lock which is not 

kept sealed in the non-release position. 

236.410.C1 Signal provided in lieu of electric or mechanical lock can display an aspect 

indicating to proceed before control circuits of signals governing movements over 

the switch have been opened. 

236.410.C2 Signal provided in lieu of electric or mechanical lock can display an aspect 

indicating to proceed before expiration of predetermined time interval, with 

approach section occupied, where approach locking is provided. 

236.410.C3 Signal provided in lieu of electric or mechanical lock can display an aspect 

indicating to proceed before expiration of predetermined time interval where time 

locking is provided. 
236-113 

§ 236.426 Interlocking rules and instructions applicable to traffic control systems.

 The rules and instructions prescribed in §§ 236.327 and 236.328, §§ 236.330 to 236.334, 

inclusive, and § 236.342 shall apply to traffic control systems.

Application: 

This rule prescribes the following interlocking rules and instructions be applied to traffic control 

systems. 

§ 236.327 Switch, movable-point frog, or split-point derail. 

§ 236.328 Plunger of facing-point lock. 

§ 236.330 Locking dog of switch-and-lock movement. 

§ 236.334 Point detector. 

§ 236.342 Switch circuit controller. 

§ 236.476 Interlocking inspections and tests applicable to traffic control systems.

 The inspections and tests prescribed in §§ 236.377 to 236.380, inclusive, and 

§§ 236.382, 236.383, and 236.386 shall apply to traffic control systems.

Application: 

This rule prescribes the following interlocking inspections and tests be made of traffic control 

systems. (See Technical Bulletin S-04-01)

§ 236.377 Approach locking. 

§ 236.378 Time locking. 

§ 236.379 Route locking. 

§ 236.380 Indication locking. 

§ 236.382 Switch obstruction test. 

§ 236.383 Valve locks, valves, and valve magnets. 

§ 236.386 Restoring feature on power switches. 

Results of tests shall be recorded in compliance with § 236.110.

Subpart E – Automatic Train Stop, Train Control, and Cab Signal Systems 

Standards 

§ 236.501 Forestalling device and speed control.

 (a) An automatic train stop system may include a device by means of which the automatic 

application of the brakes can be forestalled. 

 (b) Automatic train control system shall include one or more of the following features:

 (1) Low-speed restriction, requiring the train to proceed under slow speed after it has either 

been stopped by an automatic application of the brakes, or under control of the engineman, its 

speed has been reduced to slow speed, until the apparatus is automatically restored to normal 

because the condition which caused the restriction no longer affects the movement of the train. 

 (2) Medium-speed restriction, requiring the train to proceed under medium speed after 

passing a signal displaying an approach aspect or when approaching a signal requiring a stop, or 
236-114 

a stop indication point, in order to prevent an automatic application of the brakes.

 Note: Relief from the requirements of paragraphs (b)(1) and (2) of this section will be 

granted, insofar as speed limits fixed by definitions of Slow and Medium speeds are concerned, 

upon an adequate showing by an individual carrier where automatic train control systems now in 

service enforce speed restrictions higher than those required by definitions in §§ 236.700 to 

236.838 inclusive.

 (3) Maximum-speed restriction, effecting an automatic brake application whenever the 

predetermined maximum speed limit is exceeded. 

Application: 

This rule permits the use of a forestalling device in automatic train stop systems and sets forth 

the minimum requirements for control of speed in automatic train control systems. 

This rule applies to automatic train stop and train control systems. 

An automatic train stop system may, but is not required to, include an acknowledging device by 

means of which the automatic application of the brakes can be forestalled. 

An automatic train control system is required to have one or more of the following features: 

(1) A low-speed restriction, effective as long as the condition that causes the restriction exists, 

that prohibits movement exceeding slow speed either after the train has been stopped by 

automatic application of the brakes or its speed is reduced to slow speed by manual application 

of the brakes. 

(2) A medium-speed restriction that, in order to prevent an automatic application of the brakes, 

requires the train to proceed under medium speed after passing a signal displaying an approach 

aspect, or when approaching a signal requiring a stop, or a stop indication point. 

(3) A maximum-speed restriction that will effect an automatic brake application whenever the 

predetermined maximum authorized speed is exceeded. 

The speeds imposed by the slow-speed or medium-speed restrictions must comply with the 

carrier’s definition of slow speed or medium speed, which may not exceed that defined by §§ 

236.813 or 236.811, respectively, without approval of FRA. Each carrier establishes its own 

maximum speed. 

CLASSIFICATION OF DEFECTS

236.501.B1 Automatic train control system with low-speed restriction does not enforce slow 

speed after train has been stopped by an automatic application of the brakes, until 

the apparatus is automatically restored to normal because the condition which 

caused the restriction no longer affects the movement of the train. 

236.501.B2 Automatic train control system with low-speed restriction does not enforce slow 

speed after the speed of the train, under control of the engineman, has been 

reduced to slow speed, until the apparatus is automatically restored to normal 

because the condition which caused the restriction no longer affects the 

movement of the train. 
236-115 

236.501.B3 Automatic train control system with medium-speed restriction does not require 

train to proceed under medium speed after passing a signal displaying an 

approach aspect in order to prevent an automatic application of the brakes. 

236.501.B4 Automatic train control system with medium-speed restriction does not require 

train to proceed under medium speed when approaching a signal requiring a stop, 

or a stop indication point, in order to prevent an automatic application of the 

brakes. 

236.501.B5 Automatic train control system with maximum-speed restriction does not require 

train to proceed at or under predetermined maximum authorized speed in order to 

prevent an automatic application of the brakes. 

§ 236.502 Automatic brake application, initiation by restrictive block conditions stopping 

distance in advance. 

 An automatic train stop or train control system shall operate to initiate an automatic brake 

application at least stopping distance from the entrance to a block, wherein any condition 

described in § 236.205 obtains, and at each main track signal requiring a reduction in speed.

Application: 

This is a companion rule to § 236.504 and requires that the automatic brake application be 

initiated at least stopping distance from the entrance of a block where any condition exists as 

described in § 236.205. 

This rule applies to automatic train stop and train control systems. 

This rule requires that an automatic train stop or train control system be so arranged that it will 

operate to initiate an automatic brake application at least stopping distance in approach to a block 

wherein any condition described in § 236.205 exists, and at each main track signal requiring a 

reduction in speed. 

This rule is applicable to signals governing movements on or onto the main track. Signals on 

auxiliary tracks and sidings, whether signaled or nonsignaled, are exempt from the requirements 

of this rule. 

CLASSIFICATION OF DEFECTS

236.502.A1 Automatic train stop or train control system does not operate to initiate an 

automatic brake application at least stopping distance from the entrance to a block 

occupied by a train, locomotive, or car. 

236.502.A2 Automatic train stop or train control system does not operate to initiate an 

automatic brake application at least stopping distance from the entrance to a block 

in which the points of a switch are not closed in proper position. 

236.502.A3 Automatic train stop or train control system does not operate to initiate an 

automatic brake application at least stopping distance from the entrance to a block 
236-116 

 in which an independently operated fouling-point derail equipped with switch 

circuit controller is not in derailing position. 

236.502.A4 Automatic train stop or train control system does not operate to initiate automatic 

brake application at least stopping distance from the entrance to a block in which 

a track relay is in deenergized position, or device which functions as a track relay 

is in its most restrictive state. 

236.502.A5 Automatic train stop or train control system does not operate to initiate an 

automatic brake application at signal requiring a reduction in speed. 

§ 236.503 Automatic brake application; initiation when predetermined rate of speed 

exceeded.

 An automatic train control system shall operate to initiate an automatic brake application 

when the speed of the train exceeds the predetermined rate as required by the setting of the speed 

control mechanism.

Application: 

This is a companion rule to § 236.501 and requires overspeed protection of all restrictive features 

used in automatic train control systems. 

This rule applies to automatic train control systems only. 

This rule requires that automatic train control apparatus function to initiate an automatic brake 

application whenever the speed of the train exceeds any predetermined setting of the speed 

control mechanism. A tolerance of 3 mph is permitted in excess of the predetermined setting of 

the speed control mechanism. 

CLASSIFICATION OF DEFECTS

236.503.A1 Automatic train control system does not operate to initiate an automatic brake 

application when the speed of the train exceeds the predetermined rate as required 

by the setting of the speed control mechanism. 

§ 236.504 Operation interconnected with automatic block signal system.

 (a) A continuous inductive automatic train stop or train control system shall operate in 

connection with an automatic block signal system and shall be so interconnected with the signal 

system as to perform its intended function in event of failure of the engineer to acknowledge or 

obey a restrictive wayside signal or a more restrictive cab signal. 

 (b) An intermittent inductive automatic train stop system shall operate in connection with an 

automatic block signal system and shall be so interconnected with the signal system that the 

failure of the engineer to acknowledge a restrictive wayside signal will cause the intermittent 

inductive automatic train stop system to perform its intended function.

Application: 

This rule prescribes the interconnection and operation of an automatic train stop or train control 

system with a wayside block signal system. 
236-117 

This rule applies to automatic train stop and train control systems. 

This rule requires that an automatic train stop or train control system operate in connection with 

an automatic block signal system. The train stop or train control system must be so 

interconnected with the signal system that it will impose an automatic application of the brakes 

in event the engineer fails (1) to acknowledge or obey the indication of a wayside signal or a cab 

signal requiring a reduction in speed in a continuous inductive automatic train stop or train 

control system, or (2) to acknowledge a restrictive wayside signal in an intermittent inductive 

automatic train stop system. 

This rule is applicable only to those signals governing movements on or onto the main track. 

Signals on auxiliary tracks are exempt from the requirements of this rule. 

CLASSIFICATION OF DEFECTS

236.504.A1 Automatic train stop or train control system does not operate in connection with 

an automatic block signal system. 

236.504.A2 A continuous inductive automatic train stop or train control system not so 

interconnected with the signal system so as to perform its intended function in the 

event of failure of the engineer to acknowledge or obey a signal requiring a 

reduction in speed. 

236.504.B1 An intermittent inductive automatic train stop system not so interconnected with 

the signal system so as to perform its intended function in the event of failure of 

the engineer to acknowledge a signal requiring a reduction in speed. 

§ 236.505 Proper operative relation between parts along roadway and parts on locomotive.

 Proper operative relation between the parts along the roadway and the parts on the 

locomotive shall obtain under all conditions of speed, weather, wear, oscillation, and shock.

Application: 

This rule requires that proper operation occur between parts along the roadway and parts on the 

locomotive under all conditions. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires that apparatus on locomotives and at wayside locations be properly 

interconnected and function as intended regardless of speed, weather, wear, oscillation, and 

shock. 

CLASSIFICATION OF DEFECTS

236.505.A1 Proper operative relation between the parts along the roadway and the parts on the 

locomotive does not obtain under all conditions of speed, weather, wear, 
236-118 

oscillation, and shock. 

§ 236.506 Release of brakes after automatic application.

 The automatic train stop or train control apparatus shall prevent release of the brakes after 

automatic application until a reset device has been operated, or the speed of the train has been 

reduced to a predetermined rate, or the condition that caused the brake application no longer 

affects the movement of the train. If reset device is used, it shall be arranged so that the brakes 

cannot be released until the train has been stopped, or it shall be located so that it cannot be 

operated by engineer without leaving his/her accustomed position in the cab.

Application: 

This rule prescribes the conditions under which the brakes may be released following an 

automatic brake application. 

This rule applies to automatic train stop and train control systems. 

An intermittent inductive automatic train stop system shall not permit release of the brakes 

following an automatic brake application until after the train has been stopped. 

A continuous inductive automatic train stop system shall not permit release of the brakes 

following an automatic brake application until after the train has been stopped, unless the 

condition that caused the brake application no longer exists. 

An automatic train control system shall not permit release of the brakes following an automatic 

brake application until the speed has been reduced to a predetermined rate or until the train has 

been stopped, unless the condition that caused the brake application no longer exists. 

This rule prohibits use of a reset device in the control compartment that, when operated, permits 

release of the brakes before the train has been stopped. 

CLASSIFICATION OF DEFECTS

236.506.A1 Automatic train stop apparatus permits release of the brakes after automatic 

application before a reset device has been operated, while the condition that 

caused the brake application still affects the movement of the train. 

236.506.A2 Automatic train control apparatus permits release of the brakes after automatic 

application before the speed of the train has been reduced to a predetermined rate, 

while the condition that caused the brake application still affects the movement of 

the train. 

236.506.A3 Reset device so located that it can be operated by engineer without leaving his/her 

accustomed position in the cab and not so arranged as to prevent release of the 

brakes until the train has been stopped. 

236.506.A4 Brakes can be released following automatic brake application after reset device 

has been operated before train has been stopped, while the condition that caused 
236-119 

the brake application still affects the movement of the train. 

§ 236.507 Brake application; full service.

 The automatic train stop or train control apparatus shall, when operated, cause a full service 

application of the brakes.

Application: 

This is a companion rule to § 236.502 and requires the apparatus on the locomotive, when 

operated, to impose a full service application of the brakes. 

This rule applies to automatic train stop and train control systems. 

This rule requires that an automatic train stop or train control brake application be a full service 

brake application as defined by § 236.701. The imposition of an emergency brake application is 

prohibited. 

CLASSIFICATION OF DEFECTS

236.507.A1 Automatic train stop or train control apparatus, when operated, does not cause a 

full service application of the brakes. 

§ 236.508 Interference with application of brakes by means of brake valve.

 The automatic train stop, train control, or cab signal apparatus shall be so arranged as not to 

interfere with the application of the brakes by means of the brake valve and not to impair the 

efficiency of the brake system.

Application: 

This rule prohibits use of apparatus that affects the proper functioning of the brake system. 

This rule applies to automatic cab signal, train stop, and train control systems. 

When devices covered by this subpart are cut in service, the air passage of the automatic brake 

valve is necessarily altered, especially in train stop and train control systems. 

This rule prohibits the installation and use of apparatus that interferes with the manual 

application of the brakes by means of the independent or automatic brake valves, or that impairs 

the efficiency of the air brake or blended brake system when operated manually. 

CLASSIFICATION OF DEFECTS

236.508.A1 Automatic train stop, train control, or cab signal apparatus interferes with the 

application of the brakes by means of the brake valves. 

236.508.A2 Automatic train stop, train control, or cab signal apparatus impairs the efficiency 

of the brake system. 
236-120 

§ 236.509 Two or more locomotives coupled.

 The automatic train stop, train control, or cab signal apparatus shall be arranged so that when 

two or more locomotives are coupled, or a pushing or helping locomotive is used, it can be made 

operative only on the locomotive from which the brakes are controlled.

Application: 

This rule requires automatic train stop, train control, or cab signal apparatus be operative only on 

the locomotive from which the brakes are controlled. 

This rule applies to automatic cab signal, train stop, and train control systems. 

When two or more equipped locomotives are coupled together, or a pushing or helping 

locomotive is used, the automatic train stop, train control, or cab signal apparatus affecting 

movement of that train must be so arranged that it is operative only on the locomotive from 

which the brakes are controlled. 

CLASSIFICATION OF DEFECTS

236.509.A1 Automatic train stop, train control, or cab signal apparatus not arranged so that 

when two or more locomotives are coupled, or a pushing or helping locomotive is 

used, it can be made operative only on the locomotive from which the brakes are 

controlled. 

§ 236.511 Cab signals controlled in accordance with block conditions stopping distance in 

advance.

 The automatic cab signal system shall be arranged so that cab signals will be continuously 

controlled in accordance with conditions described in § 236.205 that obtain at least stopping 

distance in advance.

Application: 

This rule requires that automatic cab signals be continuously controlled and provide proper 

aspects and stopping distances to conditions described in § 236.205. 

Cab signals are required to be continuously controlled to indicate that speed is to be restricted 

and stop may be required at least stopping distance to all conditions described in § 236.205. 

Conditions that cause wayside false restrictive aspects such as open or crossed light circuit 

conductors or burned out lamp bulbs, except where light-out protection is provided, are exempt 

from these requirements. 

CLASSIFICATION OF DEFECTS

236.511.A1 Automatic cab signal system not so arranged that cab signals are continuously 

controlled in accordance with conditions that obtain at least stopping distance in 

advance. (Applies only to conditions described in paragraphs (a), (b), (c), and (d) 

of § 236.205.) 
236-121 

§ 236.512 Cab signal indication when locomotive enters block where restrictive conditions 

obtain.

 The automatic cab signal system shall be arranged so that when a locomotive enters or is 

within a block, wherein any condition described in § 236.205 obtains, the cab signals shall 

indicate “proceed at restricted speed.”

Application: 

This is a companion rule to § 236.514 and requires the cab signal indicate “proceed at restricted 

speed” when a locomotive enters or is within a block in cab signal territory wherein a condition 

described in 

§ 236.205 exists. 

This rule requires that the cab signal indicate “proceed at restricted speed” when the locomotive 

enters or is within a block occupied by a train, locomotive, or car; in which the points of a switch 

are not closed in proper position; in which an independently operated fouling-point derail, 

equipped with switch circuit controller, is not in derailing position; or where there are two or 

more track circuits, a track relay is in deenergized position. 

Section 236.514 permits the cab signal to change to a more favorable aspect after the train has 

passed the condition that exists or if the condition ceases to exist. 

CLASSIFICATION OF DEFECTS

236.512.A1 Automatic cab signal does not indicate “proceed at restricted speed” when 

locomotive enters or is within a block occupied by a train, locomotive, or car. 

236.512.A2 Automatic cab signal does not indicate “proceed at restricted speed” when 

locomotive enters or is within a block in which the points of a switch are not 

closed in proper position. 

236.512.A3 Automatic cab signal does not indicate “proceed at restricted speed” when 

locomotive enters or is within a block in which an independently operated 

fouling-point derail equipped with switch circuit controller is not in derailing 

position. 

236.512.A4 Automatic cab signal does not indicate “proceed at restricted speed” when 

locomotive enters a block in which a track relay is in deenergized position or 

device that functions as a track relay is in its most restrictive state. (Where there 

is more than one track circuit in the block.) 

§ 236.513 Audible indicator.

 (a) The automatic cab signal system shall be so arranged that when the cab signal changes to 

display a more restrictive aspect, an audible indicator will sound continuously until silenced by 

manual operation of an acknowledging device.

 (b) The audible cab indicator of automatic cab signal, automatic train stop, or automatic train 

control system shall have a distinctive sound and be clearly audible throughout the cab under all 

operating conditions.
236-122 

Application: 

This rule requires that when the cab signal aspect changes to a more restrictive indication, an 

audible indicator shall sound continuously until silenced by manual operation of an 

acknowledging device. It requires that the cab indicator have a distinctive sound that can be 

clearly audible throughout the cab under all conditions. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires an audible indicator be provided in cab signal systems and so arranged that it 

will sound continuously, until silenced by manual operation of an acknowledging device, when 

the cab signal changes to display a more restrictive aspect. The audible indicator may be 

electrically or pneumatically operated, must have a distinctive sound that identifies it with the 

system, and must be clearly audible throughout the cab under all operating conditions. The 

audible indicator may be so arranged that it will sound continuously during an overspeed 

condition, and silenced only by reducing to proper speed. 

Methods to silence or muffle the cab indicator, such as wrapping or plugging with paper or cloth 

or bending or breaking the air pipe to reduce air flow, are prohibited. If such tampering with this 

safety device is found, refer to § 218.55. Any individual who willfully disables or nullifies a 

safety device is subject to a civil penalty as provided in Appendix A to this part, and to 

disqualification from performing safety-sensitive functions on a railroad if found unfit for such 

duties under the procedures provided for in 49 CFR Part 209. 

CLASSIFICATION OF DEFECTS

236.513.A1 Audible cab indicator of automatic cab signal system does not sound continuously 

until silenced by manual operation of acknowledging device, when cab signal 

changes to a more restrictive aspect. 

236.513.B1 Cab indicator does not have a distinctive sound. 

236.513.B2 Cab indicator not clearly audible throughout the cab under all operating 

conditions. 

§ 236.514 Interconnection of cab signal system with roadway signal system.

 The automatic cab signal system shall be interconnected with the roadway signal system so 

that the cab signal indication will not authorize operation of the train at a speed higher than that 

authorized by the indication of the roadway signal that governed the movement of a train into a 

block except when conditions affecting movement of trains in the block change after the train 

passes the signal.

Application: 

This rule prohibits the cab signal from indicating a speed higher than that authorized by roadway 

signal indication, except when the condition changes after the roadway signal has been passed. 

This rule applies to automatic cab signal systems. 
236-123 

This rule requires the locomotive cab signal apparatus to be so interconnected to the wayside 

signal system that it will not authorize operation at a speed higher than that authorized by the 

wayside signal indication, except when conditions affecting the movement of trains in a block 

change after the train passes the wayside signal. 

These requirements apply to all signaled track in automatic cab signal territory, including 

signaled sidings and signaled auxiliary tracks. 

CLASSIFICATION OF DEFECTS

236.514.A1 Cab signal indication authorizes operation of train at a speed higher than that 

authorized by indication of roadway signal that governed movement of train into 

block. (Does not apply when conditions affecting movement of a train in the 

block change after train passes signal.) 

§ 236.515 Visibility of cab signals.

 The cab signals shall be plainly visible to member or members of the locomotive crew from 

their stations in the cab.

Application: 

This rule requires that the cab signal be so located that the locomotive crewmember or members 

can plainly see the aspect. 

This rule applies to automatic train stop, train control, and cab signal systems. 

Cab signals are required to be so installed that the crewmember or members can plainly see the 

aspect displayed from their accustomed positions in the cab. 

The cab signal is required to be properly illuminated, without cracked or broken roundels, and its 

view not obstructed by other equipment installed in the cab. If tampering with this safety device 

is found, refer to 

§ 218.55. Any individual who willfully disables or nullifies a safety device is subject to a civil 

penalty as provided in Appendix A to this part, and to disqualification from performing safetysensitive functions on a railroad if found unfit for such duties under the procedures provided for 

in 49 CFR Part 209. 

CLASSIFICATION OF DEFECTS

236.515.A1 Cab signal not plainly visible to member of locomotive crew from his/her station 

in the cab. 

§ 236.516 Power supply. 

 Automatic cab signal, train stop, or train control device hereafter installed shall operate from 

a separate or isolated power supply.

Application: 
236-124 

This rule requires that each automatic train stop, train control, or cab signal device hereafter 

installed on a locomotive operate from a separate or isolated power supply. 

This rule applies to automatic train stop, train control, and cab signal systems. 

This rule requires that the automatic train stop, train control, or cab signal device be provided 

with a dedicated power supply used solely to operate the device. It is prohibited to utilize the 

power supply to provide power to any other device or system. 

Devices installed on a locomotive prior to the effective date of February 27, 1984, are exempt 

from this requirement. 

CLASSIFICATION OF DEFECTS

236.516.A1 Automatic train stop, train control, or cab signal device not provided with an 

isolated or separate power supply. (Does not apply to devices installed prior to 

February 27, 1984.) 

236.516.A2 Power supply used to operate equipment other than automatic train stop, train 

control, or cab signal device. 

Rules and Instructions; Roadway

§ 236.526 Roadway element not functioning properly.

 When a roadway element except track circuit of automatic train stop, train control, or cab 

signal system is not functioning as intended, the signal associated with such roadway element 

shall be caused manually to display its most restrictive aspect until such element has been 

restored to normal operative condition.

Application: 

This rule requires that when the roadway element, except track circuit, of an automatic train stop, 

train control, or cab signal system has failed to perform its intended function, the associated 

signal shall be caused manually to display the most restrictive aspect. 

This rule applies to automatic train stop, train control, and cab signal systems. 

This rule requires that when a roadway element such as a tripper, inductor, loop, or electric 

circuit, except track circuit, becomes defective or is being repaired or replaced, the signal 

associated with the device must be manually caused to display its most restrictive aspect. It is 

prohibited to permit the signal to 

display a less restrictive aspect until the defective device has been restored to its normal 

operative condition. 

CLASSIFICATION OF DEFECTS

236.526.A1 Signal not caused manually to display its most restrictive aspect when roadway 

element associated with such signal is not functioning as intended. (Does not 
236-125 

apply to track circuit.) 

236.526.A2 Signal which has been caused manually to display its most restrictive aspect when 

roadway element associated with the signal is not functioning as intended, is 

caused to display a less restrictive aspect before such element has been restored to 

normal operative condition. (Does not apply to track circuit.) 

§ 236.527 Roadway element insulation resistance.

 Insulation resistance between roadway inductor and ground shall be maintained at not less 

than 10,000 ohms.

Application: 

This rule requires insulation resistance between roadway inductor winding and ground shall be 

maintained at not less than 10,000 ohms. 

This rule applies to intermittent inductive automatic train stop systems. 

This rule applies only to the roadway inductor winding. The insulation resistance of cable or 

conductors that connect the inductor to its associated signal must comply with the requirements 

of § 236.108. 

Disconnect the coil wires and test each to ground. Do not test the coils against each other with 

an insulation resistance tester. 

CLASSIFICATION OF DEFECTS

236.527.A1 Insulation resistance between roadway inductor winding and ground less than 

10,000 ohms.

§ 236.528 Restrictive condition resulting from open hand-operated switch; requirement.

 When a facing-point hand-operated switch is open one-fourth inch or more, a trailing-point 

hand-operated switch three-eighths inch or more, or hand-operated switch is not locked where 

facing-point lock with circuit controller is used, the resultant restrictive condition of an automatic 

train stop or train control device of the continuous type, or the resultant restrictive cab signal 

indication of an automatic cab signal device on an approaching locomotive shall be maintained 

to within 300 feet of the points of the switch.

Application: 

This rule requires that the restrictive condition of continuous inductive automatic train stop or 

train control device or restrictive cab signal indication of an automatic cab signal device be 

maintained to within 300 feet of an open hand-operated switch or unlocked facing-point lock in 

equipped territory. 

This rule applies to continuous inductive automatic train stop, train control, and cab signal 

systems. 
236-126 

This rule requires that switch shunting circuits or switch repeating circuits of hand-operated 

switch or facing-point lock with circuit controller effectively shunt the track circuit or open the 

signal control circuits to the extent that the restrictive condition of continuous inductive 

automatic train stop or train control device or restrictive aspect of cab signal device of an 

approaching locomotive is maintained to within 300 feet of a facing-point switch opened onefourth inch or more, a trailing point switch opened three-eighths inch or more, or a facing-point 

lock that is not locked. 

CLASSIFICATION OF DEFECTS

236.528.A1 Restrictive condition of automatic train stop or train control device of the 

continuous type on an approaching locomotive not maintained to within 300 feet 

of the points of a facing-point hand-operated switch which is open one-fourth inch 

or more. 

236.528.A2 Restrictive condition of automatic train stop or train control device of the 

continuous type on an approaching locomotive not maintained to within 300 feet 

of the points of a trailing-point hand-operated switch which is open three-eighths 

inch or more. 

236.528.A3 Restrictive condition of automatic train stop or train control device of the 

continuous type on an approaching locomotive not maintained to within 300 feet 

of the points of a hand-operated switch which is not locked, where such switch is 

equipped with facing-point lock with circuit controller. 

236.528.A4 Restrictive cab signal indication of automatic cab signal device on an approaching 

locomotive not maintained to within 300 feet of the points of a facing-point handoperated switch which is open one-fourth inch or more. 

236.528.A5 Restrictive cab signal indication of automatic cab signal device on an approaching 

locomotive not maintained to within 300 feet of the points of a trailing-point 

hand-operated switch which is open three-eighths inch or more. 

236.528.A6 Restrictive cab signal indication of automatic cab signal device on an approaching 

locomotive not maintained to within 300 feet of the points of a switch which is 

not locked, where such switch is equipped with facing-point lock with circuit 

controller. 

§ 236.529 Roadway element inductor; height and distance from rail.

 Inductor of the inert roadway element type shall be maintained with the inductor pole faces at 

a height above the plane of the tops of the rails, and with its inner edge at a horizontal distance 

from the gage side of the nearest running rail, in accordance with specifications of the carrier.

Application: 

This rule requires that inductors of the inert roadway type be installed and maintained in position 

in accordance with specifications of the carrier. 
236-127 

This rule applies to intermittent inductive automatic train stop systems. 

This rule requires that the inductor pole faces be maintained at a height above the plane of the 

tops of the rails, with its inner edge at a horizontal distance from the gage side of the nearest 

running rail in accordance with the carrier’s specifications. 

CLASSIFICATION OF DEFECTS

236.529.A1 Inductor of the inert roadway element type too high. 

236.529.A2 Inductor of the inert roadway element type too low. 

236.529.A3 Inductor of the inert roadway element too close to gage side of nearest running 

rail. 

236.529.A4 Inductor of the inert roadway element type too far from gage side of nearest 

running rail. 

§ 236.531 Trip arm; height and distance from rail.

 Trip arm of automatic train stop device when in the stop position shall be maintained at a 

height above the plane of the tops of the rails, and at a horizontal distance from its center line to 

gage side of the nearest running rail, in accordance with specifications of the carrier.

Application: 

This rule requires that trip arm of automatic train stop device, when in stop position, be installed 

and maintained in position in accordance with specifications of the carrier. 

This rule applies to mechanical trip type automatic train stop system. 

This rule requires that trip arm, when in stop position, be maintained at a height above the plane 

of the tops of the rails, with its centerline at a horizontal distance from the gage side of the 

nearest running rail in accordance with the carrier’s specifications. 

CLASSIFICATION OF DEFECTS

236.531.A1 Trip arm of automatic train stop device, in stop position, too high. 

236.531.A2 Trip arm of automatic train stop device, in stop position, too low. 

236.531.A3 Trip arm of automatic train stop device, in stop position, too close to gage side of 

running rail. 

236.531.A4 Trip arm of automatic train stop device, in stop position, too far from gage side of 

running rail. 
236-128 

§ 236.532 Strap iron inductor; use restricted.

 No railroad shall use strap iron inductor or other roadway element with characteristics 

differing from its standard type on track where speed higher than restricted speed is permitted.

Application: 

This rule restricts the use of strap iron inductors or other roadway elements with characteristics 

different from its standard type. 

This rule applies to intermittent inductive automatic train stop system. 

The use of strap iron inductors or other roadway elements with characteristics differing from its 

standard type is prohibited on track where speed is higher than 20 mph is permitted. 

CLASSIFICATION OF DEFECTS

236.532.A1 Strap iron inductor or other roadway element with characteristics differing from 

standard type used on track where speed higher than restricted speed is permitted. 

§ 236.534 Entrance to equipped territory; requirements.

 Where trains are not required to stop at the entrance to equipped territory, except when 

leaving yards and stations and speed until entering equipped territory does not exceed restricted 

speed, the automatic train stop, train control, or cab signal device shall be operative at least 

stopping distance from the entrance to such territory except where the approach thereto is 

governed by automatic approach signal.

Application: 

This rule requires that where trains are not required to stop at the entrance to equipped territory, 

except when leaving yards and stations and speed until entering equipped territory does not 

exceed restricted 

speed, the automatic train stop, train control, or cab signal device shall be operative at least 

stopping distance from the entrance to such territory except where the approach thereto is 

governed by automatic approach signal. 

This rule applies to automatic train stop, train control, and cab signal systems. 

This rule requires that automatic train stop, train control, or cab signal device be operative at 

least stopping distance from the entrance to equipped territory, except where trains are required 

to stop at the entrance to equipped territory; or the approach thereto is governed by an operative 

approach signal; or when leaving yards and stations where speed, until entering equipped 

territory, does not exceed restricted speed. 

CLASSIFICATION OF DEFECTS

236.534.A1 Automatic train stop, train control, or cab signal device not operative at least 

stopping distance from entrance to equipped territory. (Does not apply where 

trains are required to stop at entrance to equipped territory or where the approach 
236-129 

thereto is governed by automatic approach signal.) 

Rules and Instructions: Locomotive

§ 236.551 Power supply voltage; requirement.

 The voltage of power supply shall be maintained within 10 percent of rated voltage.

Application: 

This rule prescribes the tolerance within which the power supply voltage shall be maintained. 

This rule applies to automatic train stop, train control, and cab signal systems. 

The voltage of the power supply must be maintained to within 10 percent of the rated voltage. 

CLASSIFICATION OF DEFECTS

236.551.A1 Voltage of power supply more than 10 percent above rated voltage. 

236.551.A2 Voltage of power supply more than 10 percent below rated voltage. 

§ 236.552 Insulation resistance; requirement.

 When periodic test prescribed in § 236.588 is performed, insulation resistance between 

wiring and ground of continuous inductive automatic cab signal system, automatic train control 

system, or automatic train stop system shall be not less than one megohm, and that of an 

intermittent inductive automatic train stop system, not less than 250,000 ohms. Insulation 

resistance values between periodic tests shall be not less than 250,000 ohms for a continuous 

inductive automatic cab signal system, automatic train control system, or automatic train stop 

system, and 20,000 ohms for an intermittent inductive automatic train stop system.

Application: 

This rule prescribes the minimum insulation resistance permitted between wiring and ground. 

This rule applies to automatic train stop, train control, and cab signal systems. 

The insulation resistance between wiring and ground of continuous inductive automatic train 

stop, train control, and cab signal systems shall be not less than one (1) megohm when periodic 

test is performed, and not less than 250,000 ohms between periodic tests. 

The insulation resistance between wiring and ground of intermittent inductive automatic train 

stop system shall be not less than 250,000 ohms when periodic test is performed, and not less 

than 20,000 ohms between periodic tests. 

CLASSIFICATION OF DEFECTS

236.552.A1 Insulation resistance between wiring and ground of continuous inductive type 

automatic train stop, train control, or cab signal device less than 1 megohm not 
236-130 

corrected when periodic test is performed. 

236.552.A2 Insulation resistance between wiring and ground of continuous inductive type 

automatic train stop, train control, or cab signal device less than 250,000 ohms 

between periodic tests. 

236.552.A3 Insulation resistance between wiring and ground of intermittent inductive 

automatic train stop device less than 250,000 ohms not corrected when periodic 

test performed. 

236.552.A4 Insulation resistance between wiring and ground of intermittent inductive 

automatic train stop device less than 20,000 ohms between periodic tests. 

§ 236.553 Seal; where required.

 Seal shall be maintained on any device other than brake pipe cut-out cock (double-heading 

cock), by means of which the operation of the pneumatic portion of automatic train stop or train 

control apparatus can be cut out.

Application: 

This rule requires that a seal be maintained on any device other than brake pipe cut-out cock 

(double-heading cock), by means of which the operation of pneumatic portion of automatic train 

stop or train control apparatus can be cut out. 

This rule applies only to automatic train stop and train control systems. Does not apply to 

automatic cab signal systems. 

This rule requires that automatic train stop or train control apparatus be cut in and a seal applied 

to any device or cut-out cock, except double-heading cock, by means of which any part of the 

pneumatic portion of the apparatus can be cut out. The seal is required to be applied in such a 

manner that the device cannot be operated to cut out the apparatus without breaking the seal. 

CLASSIFICATION OF DEFECTS

236.553.A1 Device by means of which operation of pneumatic portion of apparatus can be cut 

out, not sealed. (Does not apply to brake pipe cut-out cock, or double-heading 

cock, of automatic 

 

 train stop or train control equipped locomotive, or to the cut-out cock for the 

pneumatic whistle of an automatic cab signal system on an equipped locomotive.) 

§ 236.554 Rate of pressure reduction; equalizing reservoir or brake pipe.

 The equalizing reservoir pressure or brake pipe pressure reduction during an automatic brake 

application shall be at a rate not less than that which results from a manual service application.

Application: 
236-131 

This is a companion rule to § 236.507 and requires that the equalizing reservoir pressure or brake 

pipe pressure reduction during an automatic brake application be at a rate not less than that 

which results from a manual service application. 

This rule applies to automatic train stop and train control systems. 

An automatic full service brake application is accomplished by piping and venting arrangements 

different than that accomplished manually. This rule requires that the efficiency of the automatic 

brake application be at least equal to the efficiency of the manual application of the brakes. 

CLASSIFICATION OF DEFECTS

236.554.A1 Equalizing reservoir or brake pipe pressure during automatic brake application 

reduces at a rate less than that which obtains during a manual service application. 

§ 236.555 Repaired or rewound receiver coil. 

 Receiver coil which has been repaired or rewound shall have the same operating 

characteristics which it possessed originally or as currently specified for new equipment.

Application: 

This rule requires that a receiver coil which has been repaired or rewound have the same 

operating characteristics which it possessed originally, or as currently specified for new 

equipment. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires receivers to be rewound with the same size wire and number of turns to 

achieve the resistive value and inductance it originally possessed or as currently specified for 

new equipment. The rule prohibits repair of receivers by removing turns of wire to eliminate 

shorts or opens. 

CLASSIFICATION OF DEFECTS

236.555.A1 Receiver coil which has been repaired or rewound does not have same operating 

characteristics which it possessed originally or as currently specified for new 

equipment. 

§ 236.556 Adjustment of relay.

 Change in adjustment of relay shall be made only in a shop equipped for that purpose except 

when receiver coils, electro-pneumatic valve, or other essential part of the equipment is replaced. 

Irregularities in power supply voltage or other variable factors in the circuit shall not be 

compensated for by adjustment of the relay.

Application: 
236-132 

This rule prohibits the adjustment of a relay elsewhere than in a shop equipped for that purpose 

except when receiver coils, electro-pneumatic valve, or other essential part of the equipment is 

replaced. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires that adjustment of relay be made only in a shop equipped for that purpose 

except when receiver coils, electro-pneumatic valve, or other essential part of the equipment is 

replaced. This rule prohibits adjustment of the relay to compensate for irregularities in power 

supply voltage or other variable factors in its circuit. 

CLASSIFICATION OF DEFECTS

236.556.A1 Change in adjustment of relay made elsewhere than in a shop equipped for that 

purpose. (Does not apply when receiver coils, electro-pneumatic valve, or other 

essential part of equipment is replaced.) 

236.556.A2 Relay adjusted to compensate for irregularities of power supply voltage or other 

variable factors in circuit. 

§ 236.557 Receiver; location with respect to rail.

 (a) Receiver of intermittent inductive automatic train stop device of the inert roadway 

element type shall be maintained with bottom of the receiver at a height above the plane of the 

tops of the rails, and with its outer edge at a horizontal distance from the gage side of the nearest 

rail, in accordance with specifications of the carrier.

 (b) Receiver of continuous inductive automatic cab signal, train stop, or train control device 

of locomotive equipped with onboard test equipment, shall be maintained with the bottom of the 

receiver at a height above the plane of the tops of the rails, and with its outer edge at a horizontal 

distance from the gage side of the nearest rail, in accordance with specifications of the carrier.

Application: 

This rule requires that the receiver of an intermittent inductive automatic train stop device, or the 

receiver of a continuous inductive automatic train stop, train control, or cab signal device on 

locomotive equipped with onboard test device, be maintained in accordance with specifications 

of the carrier. 

This rule applies to all intermittent inductive automatic train stop systems and to those 

continuous inductive automatic train stop, train control, or cab signal devices that are installed on 

locomotives equipped with onboard test device. 

This rule requires that the receiver of covered devices be maintained with bottom of the receiver 

at a height above the plane of the tops of the rails and with its outer edge at a horizontal distance 

from the gage side of the nearest rail in accordance with specifications of the carrier. 

CLASSIFICATION OF DEFECTS

236.557.A1 Receiver of intermittent inductive automatic train stop device of the inert roadway 

element type, or continuous inductive automatic train stop, train control, or cab 
236-133 

signal device on locomotive equipped with onboard test device, too high. 

236.557.A2 Receiver of intermittent inductive automatic train stop device of the inert roadway 

element type, or continuous inductive automatic train stop, train control, or cab 

signal device on locomotive equipped with onboard test device, too low. 

236.557.A3 Receiver of intermittent inductive automatic train stop device of the inert roadway 

element type, or continuous inductive automatic train stop, train control, or cab 

signal device on locomotive equipped with onboard test device, too close to gage 

side of nearest rail. 

236.557.A4 Receiver of intermittent inductive automatic train stop device of the inert roadway 

element type, or continuous inductive automatic train stop, train control, or cab 

signal device on locomotive equipped with onboard test device, too far from gage 

side of nearest rail. 

§ 236.560 Contact element, mechanical trip type; location with respect to rail. 

 Contact element of automatic train stop device of the mechanical trip type shall be 

maintained at a height above the plane of the tops of the rails, and at a horizontal distance from 

the gage side of the rail, in accordance with specifications of the carrier.

Application: 

This rule requires that the contact element of automatic train stop device of the mechanical trip 

type be maintained in accordance with specifications of the carrier. 

This rule requires that the contact element of automatic train stop device of the mechanical trip 

type be installed and maintained at a height above the tops of the plane of the rails, and at a 

horizontal distance from the nearest rail, in accordance with specifications of the carrier. 

CLASSIFICATION OF DEFECTS

236.560.A1 Contact element of automatic train stop device of the mechanical trip type too 

high. 

236.560.A2 Contact element of automatic train stop device of the mechanical trip type too 

low. 

236.560.A3 Contact element of automatic train stop device of the mechanical trip type too 

close to gage side of rail. 

236.560.A4 Contact element of automatic train stop device of the mechanical trip type too far 

from gage side of rail. 
236-134 

§ 236.562 Minimum rail current required.

 The minimum rail current required to restore the locomotive equipment of continuous 

inductive automatic train stop or train control device to normal condition or to obtain a proceed 

indication of automatic cab signal device (pick-up) shall be in accordance with specifications of 

the carrier.

Application: 

This rule requires that the minimum pick-up value of the locomotive apparatus be maintained in 

accordance with specifications of the carrier. 

This rule applies to continuous inductive automatic cab signal, train stop, and train control 

systems. 

This rule requires that minimum rail current required to restore the locomotive equipment of 

continuous inductive automatic train stop or train control device to normal condition, or to obtain 

a proceed indication of automatic cab signal device, be in accordance with specifications of the 

carrier. 

CLASSIFICATION OF DEFECTS

236.562.A1 Pick-up of locomotive equipment of continuous inductive automatic train stop, 

train control, or cab signal device too high. 

236.562.A2 Pick-up of locomotive equipment of continuous inductive automatic train stop, 

train control, or cab signal device too low. 

§ 236.563 Delay time.

 Delay time of automatic train stop or train control system shall not exceed 8 seconds and the 

spacing of signals to meet the requirements of § 236.24 shall take into consideration the delay 

time.

Application: 

This rule prescribes that the delay time of automatic train stop or train control system not exceed 

8 seconds and that the spacing of signals to meet the requirements of § 236.24 take into 

consideration the delay time. 

This rule applies to both intermittent inductive and continuous inductive automatic train stop and 

train control systems. 

Delay time is provided to give the engineer enough time to take proper action to prevent an 

automatic brake application. This rule prohibits the delay time from exceeding 8 seconds before 

the brakes begin to apply. The rule also requires that spacing of signals in equipped territory 

include the distance traveled at maximum authorized speed for 8 seconds in order that trains may 

be stopped by the automatic brake application at the signal where a stop is required, or by 

reduction in speed to the rate prescribed by the next signal in advance where reduced speed is 

required. 
236-135 

Delay time is defined in the “Definitions” section of the RS&I as follows: “§ 236.831 Time, 

delay. As applied to an automatic train stop or train control system, the time which elapses after 

the onboard apparatus detects a more restrictive indication until the brakes start to apply.” 

When a test is made to determine the delay time, the elapsed time should be measured from the 

time the onboard device recognizes the change in track circuit current or code rate, or detects the 

passage over an inductor at a signal displaying an aspect less favorable than “proceed” until the 

actuation of the valves that initiate the braking. Or to put it more simply, the delay time is 

measured from the time the cab signal or indicator changes to a more restrictive aspect, until a 

reduction in brake pipe pressure is started and the pressure in the brake cylinders starts to 

increase. In the case of the intermittent inductive train stop system, the delay time is measured 

from the instant the alarm whistle or electronic tone starts to sound until the brakes start to apply. 

The application of the brakes can be detected by watching the brake pipe pressure gauge and the 

brake cylinder gauge, and by listening for venting of air from the braking system. 

CLASSIFICATION OF DEFECTS

236.563.A1 Delay time of automatic train stop or train control system exceeds 8 seconds. 

236.563.A2 Spacing of signals to meet the requirements of § 236.24 not adequate in 

consideration of delay time during automatic train stop or train control brake 

application. 

§ 236.564 Acknowledging time.

 Acknowledging time of intermittent automatic train stop device shall be not more than 30 

seconds.

Application: 

This rule prescribes that the acknowledging time of intermittent automatic train stop device not 

exceed 30 seconds. 

This rule applies only to intermittent inductive automatic train stop systems. 

Acknowledging time is provided in order to furnish the engineer an ample time period to 

forestall an automatic brake application by holding the acknowledging lever in reverse position 

while the locomotive passes a restricting signal. This rule prohibits the acknowledging lever 

from being held in the acknowledging position longer than 30 seconds before the brakes start to 

apply. 

Acknowledging time is defined in the RS&I’s Definitions as: “§ 236.830 Time, acknowledging. 

As applied to an intermittent automatic train stop system, a predetermined time within which an 

automatic brake application may be forestalled by means of an acknowledging device.” 

The acknowledging time should be tested by moving the handle to the acknowledging position 

and holding until the brakes start to apply. The application of the brakes can be detected by 

watching the brake pipe pressure gauge for a reduction and listening for the venting of air from 

the braking system. 
236-136 

CLASSIFICATION OF DEFECTS

236.564.A1 Acknowledging time of intermittent automatic train stop device exceeds 30 

seconds. 

§ 236.565 Provision made for preventing operation of pneumatic brake-applying 

apparatus by 

 double-heading cock; requirements.

 Where provision is made for preventing the operation of the pneumatic brake-applying 

apparatus of an automatic train stop or train control device when the double-heading cock is 

placed in double-heading position, the automatic train stop or train control device shall not be cut 

out before communication is closed between the engineman’s automatic brake valve and the 

brake pipe, when operating double-heading cock toward double-heading position.

Application: 

This rule requires that where provision is made for preventing the operation of the pneumatic 

brake-applying apparatus of an automatic train stop or train control device when the doubleheading cock is placed in double-heading position, the double-heading cock shall be so arranged 

that the automatic brake valve is cut out in advance of or simultaneously with the train stop or 

train control apparatus. 

This rule applies to automatic train stop and train control systems. 

This rule prohibits operation of the double-heading cock to the extent that the automatic train 

stop or train control pneumatic apparatus is rendered inoperative before the automatic brake 

valve. 

CLASSIFICATION OF DEFECTS

236.565.A1 Automatic train stop or train control device is cut out before communication is 

closed between engineer’s automatic brake valve and the brake pipe, when 

operating double-heading cock toward double-heading position. 

§ 236.566 Locomotive of each train operating in automatic train stop, train control, or cab 

signal 

 territory; equipped. 

 The locomotive from which brakes are controlled, of each train operating in automatic train 

stop, train control, or cab signal territory shall be equipped with apparatus responsive to the 

roadway equipment installed on all or any part of the route traversed, and such apparatus shall be 

in operative condition.

Application: 

This rule requires that the locomotive, from which brakes are controlled, of each train operating 

in automatic train stop, train control, or cab signal territory shall be equipped with apparatus 

responsive to the roadway equipment installed on all or any part of the route traversed, and such 

apparatus shall be in operative condition. 
236-137 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires that each locomotive from which the brakes are controlled which traverses 

automatic train stop, train control, or cab signal territory be equipped with apparatus responsive 

to the roadway equipment installed on all or any part of the route traversed. The rule further 

requires that the apparatus of the locomotive be in operative condition upon departure from its 

initial terminal. 

CLASSIFICATION OF DEFECTS

236.566.A1 Locomotive from which brakes are controlled on train operating in automatic 

train stop, train control, or cab signal territory not equipped with apparatus 

responsive to roadway equipment installed on all or any part of route traversed. 

236.566.A2 Automatic train stop, train control, or cab signal apparatus on locomotive from 

which brakes are controlled of train operating in automatic train stop, train 

control, or cab signal territory not in operative condition. 

§ 236.567 Restrictions imposed when device fails and/or is cut out en route.

 Where an automatic train stop, train control, or cab signal device fails and/or is cut out en 

route, train may proceed at restricted speed or if an automatic block signal system is in operation 

according to signal indication but not to exceed medium speed, to the next available point of 

communication where report must be made to a designated officer. Where no automatic block 

signal system is in use train shall be permitted to proceed at restricted speed or where automatic 

block signal system is in operation according to signal indication but not to exceed medium 

speed to a point where absolute block can be established. Where an absolute block is established 

in advance of the train on which the device is inoperative train may proceed at not to exceed 79 

miles per hour.

Application: 

Section 236.566 requires that the locomotive from which brakes are controlled, of each train 

operating in automatic train stop, train control, or cab signal territory shall be equipped with 

apparatus responsive to the roadway equipment installed on all or any part of the route traversed, 

and such apparatus shall be in operative condition. 

This rule sets forth the procedures and restrictions that shall be followed when an automatic train 

stop, train control, or cab signal device fails and/or is cut out en route. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires that when an automatic cab signal, train stop, or train control device fails or is 

cut out en route, the train shall proceed not exceeding restricted speed (20 mph), or if an 

automatic block signal system is in operation according to signal indication not exceeding 

medium speed (40 mph), to the next available point of communication where a report must be 

made to a designated officer. Radio communications are permissible for this purpose. 

Following the required report, in the event the train is in territory in which an automatic block 

signal system is not in use, the train may be permitted to proceed at not exceeding restricted 
236-138 

speed (20 mph) to a point where an absolute block is established. In the event an automatic 

block signal system is in operation in the territory in which the train is operating, the train may 

be permitted to proceed according to signal indication at not exceeding medium speed (40 mph) 

to a point where an absolute block is established. 

An “absolute block” is defined by § 236.709 as “A block in which no train is permitted to enter 

while it is occupied by another train.” 

An absolute block may be established in both signaled and nonsignaled territory by use of 

manual block rules, train orders, track warrants, or another method of train operation, defined by 

the carrier’s operating rules. An absolute block may also be established in block signal territory 

by designating in the carrier’s operating rules, that when an onboard train stop or train control 

device fails, all wayside signals displaying “Restricting” or “Stop and Proceed” aspects will be 

considered to be displaying a “Stop” aspect for the train with the failed device. Thus, an 

absolute block will essentially be established in front 

of that train.Upon establishment of an absolute block in front of the train with the inoperative 

device, the train may then proceed at speeds not in excess of 79 mph. 

The carrier’s operating rules shall effect these requirements. (See Technical Bulletin S-96-03) 

CLASSIFICATION OF DEFECTS

236.567.A1 Train permitted to proceed at higher than restricted speed to next available point 

of communication when automatic train stop, train control, or cab signal device 

fails and/or is cut out en route and no automatic block signal system is in 

operation. 

236.567.A2 Train permitted to proceed at higher than medium speed to next available point of 

communication when automatic train stop, train control, or cab signal device fails 

and/or is cut out en route and an automatic block signal system is in operation. 

236.567.A3 Report not made to designated officer at next available point of communication 

after automatic train stop, train control, or cab signal device fails and/or is cut out 

en route. 

236.567.A4 Train permitted to proceed at higher than restricted speed to point where absolute 

block can be established when automatic train stop, train control, or cab signal 

device fails and/or is cut out en route and no automatic block signal system is in 

use. 

236.567.A5 Train permitted to proceed at higher than medium speed to point where absolute 

block can be established when automatic train stop, train control, or cab signal 

device fails and/or is cut out en route and an automatic block signal system is in 

use. 

236.567.A6 Train permitted to proceed at a speed exceeding 79 mph where automatic train 

stop, train control, or cab signal device fails and/or is cut out en route when an 

absolute block is established in advance of the train on which the device is 

inoperative. 
236-139 

236.567.A7 Train permitted to proceed at a speed other than restricted speed after 

communications has been established, where automatic train stop, train control, or 

cab signal device fails and/or is cut out en route when an absolute block is not 

established in advance of the train on which the device is inoperative and no 

automatic block signal system is in operation. 

§ 236.568 Difference between speeds authorized by roadway signal and cab signal; action 

required.

 If for any reason a cab signal authorizes a speed different from that authorized by a roadway 

signal, when a train enters the block governed by such roadway signal, the lower speed shall not 

be exceeded.

Application: 

The rule requires that in the event a cab signal authorizes a speed different from that authorized 

by a roadway signal, the most restrictive speed shall not be exceeded. 

This rule applies to continuous inductive automatic cab signal, train stop, and train control 

systems. 

This rule requires that if for any reason a cab signal authorizes a speed different from that 

authorized by a roadway signal, when a train enters the block governed by the signal, the lower 

speed shall not be exceeded. 

The carrier’s operating rules shall effect this requirement. 

CLASSIFICATION OF DEFECTS

236.568.A1 Train operated at a speed higher than that authorized by the more restrictive 

indication when the speed authorized by the cab signal indication is different than 

that authorized by the indication of the roadway signal when train entered block 

governed by such signal. 

Inspection and Tests: Roadway

§ 236.576 Roadway element.

 Roadway elements, except track circuits, including those for test purposes, shall be gaged 

monthly for height and alignment, and shall be tested at least every 6 months.

Application: 

This rule requires that roadway elements, except track circuits, including those for test purposes, 

shall be gaged monthly for height and alignment, and shall be tested at least once every 6 

months. 

This rule applies to automatic train stop systems. 
236-140 

This rule requires that inductor of the inert roadway type and trip arm be gaged monthly for 

height and alignment. This rule further requires testing of inductor for defective conditions in its 

winding or external controlling circuit, and of trip arm valves and return springs every 6 months. 

CLASSIFICATION OF DEFECTS

236.576.A1 Roadway element not gaged monthly for height and alignment. 

236.576.A2 Roadway element not tested at least once every 6 months. 

§ 236.577 Test, acknowledgment and cut-in circuits.

 Test, acknowledgment, and cut-in circuits shall be tested at least once every 12 months.

Application: 

This rule requires that test, acknowledgment, and cut-in circuits shall be tested at least once 

every 12 months. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires test at least once every 12 months of test circuits, including test equipment, 

acknowledgment, and cut-in circuits. 

An acknowledgment circuit is installed between the track rails at each signal or stop indication 

point in territory where an automatic train stop system of the continuous inductive type with twoindication cab signals is in service, to enforce acknowledgment by the engineer of restrictive 

conditions in order to forestall an automatic brake application. The acknowledgment circuit is 

required to be continuously energized and, if interrupted, it must deenergize its associated track 

circuit. 

A cut-in circuit is a roadway circuit located at the entrance of equipped territory by means of 

which locomotive equipment of continuous inductive type system is actuated so as to be in an 

operative condition. The cut-in circuit shall be so arranged that it requires acknowledgment by 

the engineer of all restrictive features provided by the device. 

Test circuits, including portable and onboard test equipment, may be used for performing the 

prescribed tests of apparatus on equipped locomotives. 

CLASSIFICATION OF DEFECTS

236.577.A1 Test circuit not tested at least once every 12 months. 

236.577.A2 Acknowledgment circuit not tested at least once every 12 months. 

236.577.A3 Cut-in circuit not tested at least once every 12 months. 

236.577.A4 Onboard test equipment not tested at least once every 12 months. 

Inspection and Tests; Locomotive
236-141 

§ 236.586 Daily or after trip test.

 (a) Except where tests prescribed by § 236.588 are performed at intervals of not more than 2 

months, each locomotive equipped with an automatic cab signal, train stop, or train control 

device operating in equipped territory shall be inspected for damage to the equipment and tested 

at least once each calendar day or within 24 hours before departure upon each trip.

 (b) Each equipped locomotive shall be tested to determine the locomotive equipment is 

responsive to the wayside equipment and shall be cycled to determine the device functions as 

intended. 

 (c) Each locomotive equipped with intermittent inductive automatic train stop, non-coded 

continuous inductive automatic train stop, or non-coded continuous inductive automatic train 

control device shall be tested to determine that the pick-up of the device is within specified 

limits.

Application: 

This rule prescribes inspection and test daily or after each trip of the automatic cab signal, train 

stop, or train control apparatus on each locomotive operating in equipped territory, except where 

periodic tests are performed on such locomotives at intervals of not more than 2 months. 

This rule applies to automatic cab signal, train stop, and train control systems. 

This rule requires that the automatic cab signal, train stop, or train control apparatus on each 

locomotive operating in equipped territory be inspected and tested either once every 24 hours or 

within 24 hours 

before departure on each trip. Daily or after trip inspections and tests are not required for 

locomotives which are subject to periodic tests at intervals of not more than 2 months. 

The purpose of the test is to determine the device is functioning properly before being dispatched 

into equipped territory. The test is required to be made by an employee capable of detecting 

defective conditions and taking corrective action prior to the locomotive being dispatched from 

its initial terminal. 

In all systems the daily or after trip test shall consist of a general inspection of the apparatus for 

evidence of damage or wear and a complete cycle of the system’s functions, in addition to the 

following: 

1. In intermittent inductive automatic train stop system, the test shall determine: 

a. If the apparatus is properly sensitive. 

b. That an automatic application can be forestalled. 

c. That an automatic application causes a full service application. 

d. That the brakes cannot be released during an automatic application until sufficient 

time has elapsed to stop a train from maximum authorized speed (reset time). 

e. That seals are properly applied unless device is to be cut out between initial terminal 

and equipped territory. 

2. In continuous inductive automatic train stop system, the test shall determine that: 

a. An automatic application can be forestalled. 
236-142 

b. An automatic application causes a full service brake application. 

c. The brakes cannot be released during an automatic application until sufficient time 

has elapsed to stop a train from maximum authorized speed (reset time), or the 

condition that caused the automatic application ceases to exist, and in non-coded 

continuous inductive automatic train stop system, that pick-up of the device is within 

specified limits. 

d. Seals are properly applied unless device is to be cut out between initial terminal and 

equipped territory. 

3. In continuous inductive automatic train control system, the test shall determine that: 

a. Overspeed causes an automatic brake application unless suppressed. 

b. An automatic application causes a full service brake application. 

c. The brakes cannot be released during an automatic application until sufficient time 

has elapsed to stop a train from maximum authorized speed (reset time) or the speed 

of the train has been slowed to a predetermined rate, or the condition that caused the 

automatic application ceases to exist, and in non-coded continuous inductive 

automatic train control system, that pick-up of the device is within specified limits. 

d. Seals are properly applied unless device is to be cut out between initial terminal and 

equipped territory. 

4. In automatic cab signal system, the test shall determine that: 

a. Cab signal indications correspond to proper codes or track conditions. 

b. The audible indicator has a distinctive sound and can be heard clearly throughout the 

cab. 

c. The audible indicator sounds continuously until silenced manually each time the cab 

signal changes to a more restrictive indication. 

Results of the daily or after trip test are required to be recorded in accordance with § 236.110. 

CLASSIFICATION OF DEFECTS

236.586.A1 Automatic train stop, train control, or cab signal apparatus on locomotive 

operating in equipped territory not tested either once every 24 hours, or within 24 

hours before 

 departure on each trip. (Does not apply to locomotive on which periodic test is 

made at least once every 2 months.) 

236.586.B1 Equipped locomotive not tested to determine the locomotive equipment is 

responsive to the wayside equipment, or not cycled to determine the device 

functions as intended. 

236.586.C1 Locomotive equipped with intermittent inductive automatic train stop, non-coded 

continuous inductive automatic train stop, or non-coded continuous inductive 

automatic train control device, not tested to determine that the pick-up of the 

device is within specified limits. 
236-143 

§ 236.587 Departure test.

 (a) The automatic train stop, train control, or cab signal apparatus on each locomotive, except 

a locomotive or a multiple-unit car equipped with mechanical trip stop, shall be tested using one 

of the following methods:

 (1) Operation over track elements;

 (2) Operation over test circuit;

 (3) Use of portable test equipment; or

 (4) Use of onboard test device.

 (b) The test shall be made on departure of the locomotive from its initial terminal unless that 

apparatus will be cut out between the initial terminal and the equipped territory. If the apparatus 

is cut out between the initial terminal and the equipped territory, the test shall be made prior to 

entering equipped territory.

 (c) If a locomotive makes more than one trip in any 24-hour period, only one departure test is 

required in such 24-hour period. 

 (d)(1) Whoever performs the test shall certify in writing that such test was properly 

performed. The certification and the test results shall be posted in the cab of the locomotive and 

a copy of the certification and test results left at the test location for filing in the office of the 

supervisory official having jurisdiction.

 (2) If it is impractical to leave a copy of the certification and test results at the location of the 

test, the test results shall be transmitted to either (i) the dispatcher or (ii) one other designated 

individual at each location, who shall keep a written record of the test results and the name of the 

person performing the test. These records shall be retained for at least 92 days.

Application: 

This rule requires that the automatic train stop, train control, or cab signal apparatus on each 

locomotive be tested prior to entering equipped territory to determine if such apparatus is in 

service and functioning properly. 

This rule applies to automatic cab signal, train stop, and train control systems, except automatic 

train stop system of the mechanical trip type. 

This rule requires the departure test be made on departure of the locomotive from its initial 

terminal or before it enters equipped territory. If the apparatus is cut out between initial terminal 

and equipped territory, the departure test must be made prior to entering equipped territory. 

The purpose of the test is to determine the apparatus is in service and is functioning properly. 

This rule permits departure tests to be made over track elements or test circuits permanently 

installed for that purpose, with portable test equipment, or with onboard test equipment. In any 

case, it must be so arranged that it will produce any of the various track circuit, or restrictive 

conditions encountered in actual service. 

If a locomotive makes more than one trip in a 24-hour period, only one departure test is required 

in such 24-hour period. 

Section 236.587 requires that whoever performs the test shall certify in writing that the test was 

made and that the certification and results of the tests shall be posted in the cab of the 

locomotive. Further, a copy of the certification and results of the tests is required to be left at the 
236-144 

test location for filing in the office of the supervisory official having jurisdiction. If these 

records are left in some type of repository (e.g., mailbox) at the test location, it shall be of a 

design to provide reasonable protection from the elements (e.g., wind, rain, snow, etc.). 

Furthermore, all such test records left at outlying test locations must be picked up in a timely 

manner (e.g., at least once a week) and filed in the locomotive office nearest the test point 

locations. These records are required to be available for inspection and copying during normal 

business hours. 

This rule takes cognizance of locations where it is impractical for a copy of the test to be left at 

the location being tested, by providing that the results of the tests may be transmitted to either the 

dispatcher or to one other designated individual at each location. In either case, the employee 

who receives the information is required to keep a written record of the results of the tests and 

the name of the person performing the tests. 

This rule does not permit the railroad to use a third party for reporting purposes, should the 

person designated not be available for reporting of departure tests. If the designated person is 

not available, the engineer must report the results of the departure test and the name of the person 

making such test to the dispatcher, or else leave a written record of such test at the test location. 

The records of departure tests must be retained for at least 92 days. Note: § 236.110 also 

requires that a record be made of the departure test. 

 

CLASSIFICATION OF DEFECTS

236.587.A1 Departure test of automatic train stop, train control, or cab signal apparatus on 

locomotive not made by an acceptable method. 

236.587.B1 Test of automatic train stop, train control, or cab signal apparatus on locomotive 

not made on departure of locomotive from its initial terminal if equipment on 

locomotive is not cut out between its initial terminal and equipped territory. 

(Does not apply to locomotives and multiple-unit cars equipped with mechanical 

trip stop, or locomotives making more than one trip in each 24 hours where a 

departure test has been made on the locomotive equipment within the 

corresponding 24-hour period.) 

236.587.B2 Test of automatic train stop, train control, or cab signal apparatus on locomotive 

not made immediately prior to entering equipped territory, if equipment on 

locomotive is cut out between its initial terminal and equipped territory. 

236.587.C1 Automatic train stop, train control, or cab signal apparatus on locomotive making 

more than one trip within a 24-hour period not given a departure test within the 

corresponding 24-hour period. 

236.587.D1 Record of departure test of automatic train stop, train control, or cab signal 

equipment on locomotive not signed by employee making test. 

236.587.D2 Record of departure test of automatic train stop, train control, or cab signal 

equipment not posted in cab of locomotive. 

236.587.D3 Record of departure test of automatic train stop, train control, or cab signal 

equipment on locomotive not kept, at test location. (Does not apply where 
236-145 

impractical and, in lieu thereof, certification and results of test are transmitted to 

the dispatcher or the designated individual.) 

236.587.D4 Record of departure test of automatic train stop, train control, or cab signal 

equipment on locomotive not transmitted to dispatcher or the designated 

individual. (Does not apply where it is practical to leave copy of record at test 

location.)

§ 236.588 Periodic test.

 Except as provided in § 236.586, periodic test of the automatic train stop, train control, or cab 

signal apparatus shall be made at least once every 92 days, and on multiple-unit cars as specified 

by the carrier, subject to approval by the FRA.

Application: 

This rule requires that, except as provided in § 236.586, periodic tests of the automatic train stop, 

train control, or cab signal apparatus shall be made at least once every 92 days, and on multipleunit cars as specified by the carrier, subject to approval by FRA. 

This rule applies to automatic cab signal, train stop, and train control systems. 

In keeping with § 236.586, the prescribed 92-day requirement of this rule is not applicable where 

periodic tests are made on locomotives at intervals of not more than 2 months. No other 

deviation from these requirements is permissible without approval of FRA. 

The daily or after trip test prescribed by § 236.586 is a test to determine the device is in good 

condition and functioning properly before being dispatched into equipped territory. The 

departure test prescribed by § 236.587 is a test to determine that the device is turned on, in 

service, and functioning as intended before actually departing into equipped territory. The 

purpose of the periodic test prescribed by § 236.588 is to provide a more thorough and in-depth 

test and inspection of the electrical and pneumatic equipment. 

All defective conditions shall be immediately corrected during the periodic test which shall 

consist of at least the following tests and inspections: 

1. Thorough examination of the electrical portion including measurement of the insulation 

resistance. 

2. Measurement of the power supply voltage. 

3. Measurement of the pick-up value required to restore the device to normal condition. 

4. Measurement of the release value of the device in continuous non-coded systems. 

5. Test of sensitivity of intermittent inductive automatic train stop system. 

6. Measurement of acknowledging time. 

7. Measurement of delay time. 
236-146 

8. Measurement of reset time in train stop and train control systems. 

9. Measurement of height of receiver of intermittent inductive automatic train stop and 

continuous inductive systems having onboard test equipment, and of tripper of 

mechanical trip stop system. 

10. Test of audible indicator. 

11. Replacement of relays with dates that expire prior to next scheduled periodic test. 

12. Replacement of pneumatic apparatus with cleaning dates that expire prior to next 

scheduled periodic test. 

13. Measurement of accuracy of governor in train control systems. 

14. Cycle test of apparatus to determine that it functions as intended. 

Section 236.110 requires that the results of periodic tests be recorded on a form provided for that 

purpose. 

CLASSIFICATION OF DEFECTS

236.588.A1 Periodic tests of automatic train stop, train control, or cab signal apparatus not 

made at least once every 92 days. 

236.588.A2 Periodic tests of automatic train stop, train control, or cab signal apparatus not 

made at least once every 2 months where daily or after trip test is not performed. 

236.588.A3 Periodic tests of automatic train stop, train control, or cab signal apparatus on 

multiple-unit car not made at periods specified by carrier, and approved by the 

FRA. 

§ 236.589 Relays.

 (a) Each relay shall be removed from service, subjected to thorough test, necessary repairs 

and adjustments made, and shall not be replaced in service unless its operating characteristics are 

in accordance with the limits within which such relay is designed to operate, as follows: 

 

 (1) Master or primary relays of torque type depending on spring tension to return contacts to 

deenergized position in non-coded continuous inductive automatic train stop or train control 

system, at least once every 2 years; and 

 (2) All other relays, at least once every 6 years.

Application: 

This rule requires that each relay, except master or primary relay of torque type, be removed 

from service and shopped at least once every 6 years. Master or primary relay of torque type 

depending on spring tension to return contacts to deenergized position shall be removed from 

service and shopped at least once every 2 years. 
236-147 

This rule applies to automatic cab signal, train stop, and train control systems. 

The rule requires that each relay be removed from service as prescribed, subjected to thorough 

test, and necessary repairs and adjustment made. 

The rule prohibits the relay from being returned to service unless its operating characteristics are 

in accordance with the limits within which such relay is designed to operate. In order to preclude 

loss of shelf time, a date tag may be applied showing when the relay was placed in service. In 

the absence of a date tag, or where the date is altered or illegible, the shop date of the relay will 

be used to determine when the relay should be removed from service. 

CLASSIFICATION OF DEFECTS

236.589.A1 Master or primary relay of torque type depending on spring tension to return 

contacts to deenergized position of non-coded system not removed from service 

for test and necessary repairs and adjustment at least once every 2 years. 

236.589.A2 Relay, other than a master or primary relay of torque type, not removed from 

service for test and necessary repairs and adjustment at least once every 6 years. 

236.589.A3 Relay replaced in service after test and repair with operating characteristics not in 

accordance with the limits within which such relay is designed to operate. 

§ 236.590 Pneumatic apparatus.

 Automatic train stop, train control, or cab signal pneumatic apparatus shall be inspected, 

cleaned, and the results of such inspection recorded as provided by § 229.29(a). When a 

locomotive with automatic train stop, train control, or cab signal pneumatic apparatus receives 

out-of-use credit pursuant to § 229.33, the automatic train stop, train control, or cab signal 

apparatus shall be tested in accordance with § 236.588 prior to the locomotive being placed in 

service.

Application: 

This rule requires that automatic train stop, train control, or cab signal pneumatic apparatus be 

inspected, cleaned, and the results of such inspection recorded as provided by § 229.29(a). 

This rule applies to automatic train stop, train control, and cab signal systems. 

This rule requires that pneumatic apparatus of the automatic train stop, train control, or cab 

signal device be inspected and cleaned at least once every 736 days. 

The results of such inspection are to be recorded as provided by § 229.29. 

When a locomotive with automatic train stop, train control, or cab signal pneumatic apparatus 

receives out-of-use credit pursuant to § 229.33, the automatic train stop, train control, or cab 

signal apparatus shall be tested in accordance with § 236.588 prior to the locomotive being 

placed in service. 
236-148 

§ 236.590 Pneumatic apparatus. 

Automatic train stop, train control, or cab signal pneumatic apparatus shall be inspected, cleaned, 

and the results of such inspection recorded as provided by § 229.29(a). When a locomotive with 

automatic train stop, train control, or cab signal pneumatic apparatus receives out-of-use credit 

pursuant to § 229.33, the automatic train stop, train control, or cab signal apparatus shall be 

tested in accordance with § 236.588 prior to the locomotive being placed in service. 

 

CLASSIFICATION OF DEFECTS

236.590.A1 Automatic train stop, train control, or cab signal pneumatic apparatus not 

inspected and cleaned at least once every 736 calendar days. 

236.590.A2 Automatic train stop, train control, or cab signal pneumatic apparatus not 

inspected and cleaned as provided by § 229.29. 

236.590.A3 The results of inspection and cleaning not recorded as provided by § 229.29. 

TECHNICAL BULLETINS

SUBJECT: CLASSIFICATION OF DEFECTS CODES FOR HARMON 

AUTOMATIC TRAIN CONTROL USED ON CONRAIL.

NUMBER: TB-89-2 ORIGINAL ISSUE NUMBER AND DATE: 1-18-89

DISCIPLINE: SIGNAL AND TRAIN CONTROL 

REISSUE DATES:_______________________________________________ 

On November 19, 1987, the Federal Railroad Administration issued a Notice of Final Orders of 

Particular Applicability (52 FR 44513) requiring that all trains operating on the Northeast 

Corridor (NEC) spine be controlled by locomotives equipped with automatic train control 

(ATC). At the time of issuance of those orders, FRA was conducting analyses to determine the 

optimally safe braking specifications for ATC devices on freight trains on the NEC. The FRA 

concluded its study and determined that ATC does not present any undue safety risk for freight 

service on the NEC. On January 19, 1988, FRA issued its supplement to the Final Orders of 

Applicability (53 FR 1433) that established specifications for a 

microprocessor based ATC system for freight train operation on the NEC. These specifications 

do not apply to passenger train operations. 

Conrail is in the process of placing a microprocessor-based ATC device (braking profile system 

(BPS)) in service on 100 freight locomotives operating in the NEC. The Providence and 

Worchester Railroad has indicated it will install the same type ATC device as Conrail. The 

device is manufactured by Harmon Electronics and is programed with braking curves that permit 

the locomotive engineer to control the train by means other than a brake application as long as 

the train speed is within the parameters of the braking profile. Thus, this device provides 

equivalent protection as conventional ATC without the necessity of severe braking to forestall a 

penalty brake application. 
236-149 

The following is a paragraph-by-paragraph of FRA’s specifications followed by enforcement 

instructions for S&TC inspectors. 

*Supplement to Final Orders: 

In consideration of the foregoing, the Final Orders of Particular Applicability issued November 

19, 1987, are supplemented as follows; 

1. “Use of conventional ATC on freight train locomotives on the NEC is safe. 

Conventional ATC, which makes use of temporary suppression, results at most, in 

only moderate increases in buff forces. By careful use of the throttle during a 

temporary suppression application, the buff forces can be reduced. Therefore, no 

modification or specification changes are necessary for conventional ATC 

installation on freight train locomotives on the NEC.” 

For conventional Systems cite defective conditions using the classification of Defect Codes. 

2. “Conrail’s proposed ATC system utilizing a braking profile system, when used in 

conjunction with automatic cab signals supplemented with ATS, provides a safe 

alternative to conventional ATC systems.” It is an acceptable ATC system for use 

on controlling locomotives of NEC freight train provided that: 

A. The BPS system complies with all provisions of 49 CFR Part 236 that apply to 

ATC systems, except as modified herein: 

B. “The BPS system shall operate to initiate an automatic brake application at 

least stopping distance from the entrance to a block in which any condition 

described in § 236.205 exists”; 

Cite conditions that do not comply with paragraph 2B using Classification of 

Defect Codes 502.01, 502.02, 502.03, and 502.04. 

C. “The BPS system shall operate to require a reduction in speed to that 

prescribed by a main track signal requiring a reduction in speed;” 

 

Cite conditions that do not comply with paragraph 2C using Classification of 

Defect Code 502.05. 

D. “The BPS system shall operate to initiate an automatic brake application 

within 27 seconds after the locomotive, at speeds exceeding 20 mph, enters or 

is within a block described in § 236.205 occurs;” 

Cite conditions that do not comply with paragraph 2D using Classification of 

Defect Code 235.5.05 and show the appropriate defect below in the 

ADescription@ column on the Signal and Train Control inspection report Form 

F 6180.5. 

-- Automatic train control does not operate to initiate an automatic brake 

application within 27 seconds after the locomotive, at speeds above 20 mph, 

enters or is within a block occupied by a train, locomotive, or car. 
236-150 

-- Automatic train control system does not operate to initiate an automatic 

brake application within 27 seconds after the locomotive, at speeds above 20 

mph, enters or is within a block in which the points of a switch are not closed 

in proper position. 

-- Automatic train control system does not operate to initiate an automatic 

brake application within 27 seconds after the locomotive, at speeds above 20 

mph, enters or is within a block in which an independently operated foulingpoint derail equipped with switch circuit controller is not in derailing 

position. 

-- Automatic train control system does not operate to initiate an automatic 

brake application within 27 seconds after the locomotive, at speeds above 20 

mph, enters or is within a block in which a track relay is in deenergized 

position or device which functions as a track relay is in its most restrictive 

state. (Where there is more than one track circuit in the block.) 

E. “The BPS system shall operate to initiate an automatic brake application 

when speed of the train exceeds the rate permitted by the braking profile 

curve;” 

Cite conditions that do not comply with paragraph 2E using Classification of 

Defect Code 501.05. 

F. “The BPS system shall operate to initiate an automatic brake application if the 

system is deactivated while the speed of the locomotive exceeds 20 mph;” 

Cite conditions that do not comply with paragraph 2F using Classification of 

Defect Code 235.5.05 followed by the defect code below in the “Description” 

column on the Signal and Train Control inspection report Form F 6180.5. 

-- Automatic train control system does not operate to initiate an automatic brake 

application when the system is deactivated while speed of the locomotive 

exceeds 20 mph. 

G. “The visual display of the status of BPS is plainly visible to members of the 

locomotive crew from their stations in the cab;” 

Cite conditions that do not comply with paragraph 2G using Classification of 

Defect Code 235.5.05 followed by the defect code below in the “Description” 

column on the Signal and Train Control inspection report Form F 6180.5. 

 
236-151 

-- Automatic train control display not plainly visible to member of locomotive 

crew from his/her station in the cab. 

 H. “Indicators clearly visible from track side on both sides of each equipped 

locomotive are illuminated when BPS is activated and operating properly, and 

extinguished at all other times;” 

Cite conditions that do not comply with Paragraph 2H using Classification of 

Defect Code 235.5.05 followed by the defect code below in the “Description” 

column on the Signal and Train Control inspection Form F 6180-5. 

-- Indicator on side of locomotive not clearly visible from track side when ATC 

system is activated and functioning as intended. 

-- Indicator on side of locomotive not illuminated when ATC system is activated 

and functioning as intended. 

-- Indicator on side of locomotive not extinguished when ATC system is 

deactivated. 

I. “The BPS system shall be connected to an operating event recorder which 

records each instance of activation and deactivation of the BPS so that the 

time and location of each activation and deactivation can be determined for at 

least 48 hours following that event;” 

Cite conditions that do not comply with paragraph 2I using Classification of 

Defect Code 235.5.05 followed by the appropriate defect code below in the 

“Description” column on the Signal and Train Control inspection report 

Form F 6180.5. 

-- Automatic train control system not connected to an operating event recorder. 

-- Event recorder does not record when ATC system is deactivated. 

-- Event recorder does not record when ATC is activated. 

-- Time and location ATC system is activated or deactivated cannot be 

determined for at least 48 hours. 

J. “Each profile braking curve program shall be identified by a unique 

identifying number that can be displayed on the BPS visual display for 

identification purposes;” 

Cite conditions that do not comply with Paragraph 2J using Classification of 

Defect Code 235.5.05 followed by the appropriate defect code below in the 

“Description” column on the Signal and Train Control inspection report 

Form F 6180.5. 

-- Profile braking curve identifying number not displayed on ATC system 

display unit. 
236-152 

-- Profile braking curve identifying number not currently in effect. 

-- More than one profile braking curve currently in effect. 

K. “All components in the control circuits including, but not limited to 

programmable chips, are permanently installed by soldering;” 

Cite conditions that do not comply with paragraph 2K using Classification of 

Defect Code 235.5.05 followed by the defect below in the “Description” 

column on the Signal and Train Control inspection report Form F 6180.5. 

-- Control circuit component not soldered in place. 

L. “Installation is permanent on each controlling locomotive designated for 

operation on the NEC;” 

Cite conditions that do not comply with paragraph 2L using Classification of 

Defect Code 235.5.05 followed by the defect below in the “Description” 

column on the Signal and Train Control inspection report Form F 6180.5. 

-- Automatic train control system not permanently installed on locomotive. 

M. “Conrail and Amtrak issue operating rules governing operations of 

locomotives equipped with the BPS system that are in compliance with Part 

236 and specifically address the situation in which the speed control system 

fails or is cut out en route;” and, 

Cite conditions that do not comply with paragraph 2M using Classification of 

Defect Codes 567.01, 567.02, 567.03, 567.04, 567.05, and 567.06. 

N. “No train having a controlling locomotive with a failed or cut-out BPS 

system is permitted to depart its last terminal before entering the NEC.” 

Cite conditions that do not comply with paragraph 2N using Classification of 

Defect Code 566.02. 

3. “Nothing contained herein, or in the Final Orders issued November 16, 1987, 

permits operation of non-ATC-equipped controlling locomotives after dates 

specified in the Final Orders. Carriers desiring to operate non-ATC-equipped 

locomotives in switching, transfer or work train service must petition FRA for relief 

on a case-by-case basis through the waiver process as provided in 

49 CFR Part 235.” 

Cite conditions that do not comply with paragraph 3 using Classification of Defect 

Code 566.01. 
236-153 

Subpart F – Dragging Equipment and Slide Detectors and Other Similar Protective 

Devices 

Standards

§ 236.601 Signals controlled by devices; location. 

 Signals controlled by devices used to provide protection against unusual contingencies, such 

as 

landslides, dragging equipment, burned bridges or trestles, and washouts shall be located so that 

stopping distance will be provided between the signal and the point where it is necessary to stop 

the train.

Application:

This rule requires that signals controlled by devices to protect against unusual contingencies such 

as landslides, dragging equipment, burned bridges or trestles, washouts, etc., shall be located so 

that stopping distance will be provided between the signal and the point where it is necessary to 

stop the train. 

This rule is applicable to all signals or systems governing the movement of trains into one or 

more blocks that are not covered in Subparts B, C, D, and E of Part 236. 

Part 236, Subpart A, contains the applicable sections to use when citing defective conditions of 

devices or systems covered by this rule. 

Such protective devices are installed as safety features and shall not be removed without 

approval of FRA unless the condition that warranted their installation ceases to exist. If for some 

reason the signals or devices are removed from service for a temporary period, the carrier shall 

take appropriate measures to protect safety of train operation. 

CLASSIFICATION OF DEFECTS

236.601.A1 Signal controlled by device used to provide protection against unusual 

contingencies, such as landslides, dragging equipment, burned bridges or trestles, 

and washouts not located so that stopping distance is provided between the signal 

and the point where it is necessary to stop the train. 

Subpart G – Definitions

§ 236.700 Definitions. 

 For the purpose of these rules, standards, and instructions, the following definitions will 

apply. 

§ 236.701 Application, brake; full service. 

 An application of the brakes resulting from a continuous or a split reduction in brake pipe 

pressure at a service rate until maximum brake cylinder pressure is developed. As applied to an 
236-154 

automatic or electro-pneumatic brake with speed governor control, an application other than 

emergency which develops the maximum brake cylinder pressure, as determined by the design of 

the brake equipment for the speed at which the train is operating. 

§ 236.702 Arm, semaphore. 

 The part of a semaphore signal displaying an aspect. It consists of a blade fastened to a 

spectacle. 

§ 236.703 Aspect. 

 The appearance of a roadway signal conveying an indication as viewed from the direction of 

an approaching train; the appearance of a cab signal conveying an indication as viewed by an 

observer in the cab. 

§ 236.704 [Reserved]

§ 236.705 Bar, locking. 

 A bar in an interlocking machine to which the locking dogs are attached. 

§ 236.706 Bed, locking. 

 That part of an interlocking machine that contains or holds the tappets, locking bars, crosslocking, dogs, and other apparatus used to interlock the levers. 

§ 236.707 Blade, semaphore. 

 The extended part of a semaphore arm which shows the position of the arm. 

§ 236.708 Block. 

 A length of track of defined limits, the use of which by trains is governed by block signals, 

cab signals, or both. 

§ 236.709 Block, absolute. 

 A block in which no train is permitted to enter while it is occupied by another train. 

§ 236.710 Block, latch. 

 The lower extremity of a latch rod which engages with a square shoulder of the segment or 

quadrant to hold the lever in position. 

§ 236.711 Bond, rail joint. 

 A metallic connection attached to adjoining rails to ensure electrical conductivity. 
236-155 

§ 236.712 Brake pipe. 

 A pipe running from the engineman's brake valve through the train, used for the transmission 

of air under pressure to charge and actuate the automatic brake equipment and charge the 

reservoirs of the electro-pneumatic brake equipment on each vehicle of the train. 

§ 236.713 Bridge, movable. 

 That section of a structure bridging a navigable waterway so designed that it may be 

displaced to permit passage of traffic on the waterway. 

§ 236.714 Cab. 

 The compartment of a locomotive from which the propelling power and power brakes of the 

train are manually controlled. 

§ 236.715-716 [Reserved] 

§ 236.717 Characteristics, operating. 

 The measure of electrical values at which electrical or electronic apparatus operate (e.g., 

drop-away, pick-up, maximum and minimum current, and working value). 

 [49 FR 3387, Jan. 26, 1984] 

§ 236.718 Chart, dog. 

 A diagrammatic representation of the mechanical locking of an interlocking machine, used as 

a working plan in making up, assembling, and fitting the locking. 

§ 236.719 Circuit, acknowledgment. 

 A circuit consisting of wire or other conducting material installed between the track rails at 

each signal in territory where an automatic train stop system or cab signal system of the 

continuous inductive type with 2-indication cab signals is in service, to enforce 

acknowledgement by the engineman at each signal displaying an aspect requiring a stop. 

§ 236.720 Circuit, common return. 

 A term applied where one wire is used for the return of more than one electric circuit. 

§ 236.721 Circuit, control. 

 An electrical circuit between a source of electric energy and a device which it operates. 

§ 236.722 Circuit, cut-in. 

 A roadway circuit at the entrance to automatic train stop, train control, or cab signal territory 

by means of which locomotive equipment of the continuous inductive type is actuated so as to be 

in operative condition. 
236-156 

§ 236.723 Circuit, double wire; line. 

 An electric circuit not employing a common return wire; a circuit formed by individual wires 

throughout. 

§ 236.724 Circuit, shunt fouling. 

 The track circuit in the fouling section of a turnout, connected in multiple with the track 

circuit in the main track. 

§ 236.725 Circuit, switch shunting. 

 A shunting circuit which is closed through contacts of a switch circuit controller. 

§ 236.726 Circuit, track. 

 An electrical circuit of which the rails of the track form a part. 

§ 236.727 Circuit, track; coded. 

 A track circuit in which the energy is varied or interrupted periodically. 

§ 236.728 Circuit, trap. 

 A term applied to a circuit used where it is desirable to provide a track circuit but where it is 

impracticable to maintain a track circuit. 

§ 236.729 Cock, double-heading. 

 A manually operated valve by means of which the control of brake operation is transferred to 

the leading locomotive. 

§ 236.730 Coil, receiver. 

 Concentric layers of insulated wire wound around the core of a receiver of an automatic train 

stop, train control, or cab signal device on a locomotive. 

§ 236.731 Controller, circuit. 

 A device for opening and closing electric circuits. 

§ 236.732 Controller, circuit; switch. 

 A device for opening and closing electric circuits, operated by a rod connected to a switch, 

derail, or movable-point frog. 
236-157 

§ 236.733 Current, foreign. 

 A term applied to stray electric currents which may affect a signaling system, but which are 

not a part of the system. 

§ 236.734 Current of traffic. 

 The movement of trains on a specified track in a designated direction. 

§ 236.735 Current, leakage. 

 A stray electric current of relatively small value which flows through or across the surface of 

insulation when a voltage is impressed across the insulation. 

§ 236.736 Cut-section. 

 A location other than a signal location where two adjoining track circuits end within a block. 

§ 236.737 Cut-section, relayed. 

 A cut-section where the energy for one track circuit is supplied through front contacts or 

through front and polar contacts of the track relay for the adjoining track circuit. 

§ 236.738 Detector, point. 

 A circuit controller which is part of the switch operating mechanism and operated by a rod 

connected to a switch, derail, or movable-point frog to indicate that the point is within a specified 

distance of the stock rail. 

§ 236.739 Device, acknowledging. 

 A manually operated electric switch or pneumatic valve by means of which, on a locomotive 

equipped with an automatic train stop or train control device, an automatic brake application can 

be forestalled, or by means of which, on a locomotive equipped with an automatic cab signal 

device, the sounding of the cab audible indicator can be silenced. 

§ 236.740 Device, reset. 

 A device whereby the brakes may be released after an automatic train control brake 

application. 

§ 236.741 Distance, stopping. 

 The maximum distance on any portion of any railroad which any train operating on such 

portion of railroad at its maximum authorized speed, will travel during a full service application 

of the brakes, between the point where such application is initiated and the point where the train 

comes to a stop. 
236-158 

§ 236.742 Dog, locking. 

 A steel block attached to a locking bar or tappet of an interlocking machine, by means of 

which locking between levers is accomplished. 

§ 236.743 Dog, swing. 

 A locking dog mounted in such a manner that it is free to rotate on a trunnion which is 

riveted to a locking bar. 

 Cross Reference: Element, contact. See receiver, § 236.788. 

§ 236.744 Element, roadway. 

 That portion of the roadway apparatus of automatic train stop, train control, or cab signal 

system, such as electric circuit, inductor, or trip arm to which the locomotive apparatus of such 

system is directly responsive. 

 [49 FR 3387, Jan. 26, 1984] 

§ 236.745 Face, locking. 

 The locking surface of a locking dog, tappet, or cross-locking of an interlocking machine. 

§ 236.746 Feature, restoring. 

 An arrangement on an electro-pneumatic switch by means of which power is applied to 

restore the switch movement to full normal or to full reverse position, before the driving bar 

creeps sufficiently to 

unlock the switch, with control level in normal or reverse position. 

 [49 FR 3388, Jan. 26, 1984] 

§ 236.747 Forestall. 

 As applied to an automatic train stop or train control device, to prevent an automatic brake 

application by operation of an acknowledging device or by manual control of the speed of the 

train. 

§ 236.748 [Reserved] 

§ 236.749 Indication. 

 The information conveyed by the aspect of a signal. 

 Cross Reference: Inductor, see § 236.744. 

§ 236.750 Interlocking, automatic. 

 An arrangement of signals, with or without other signal appliances, which functions through 

the exercise of inherent powers as distinguished from those whose functions are controlled 

manually, and which are so interconnected by means of electric circuits that their movements 

must succeed each other in proper sequence, train movements over all routes being governed by 

signal indication. 
236-159 

§ 236.751 Interlocking, manual. 

 An arrangement of signals and signal appliances operated from an interlocking machine and 

so interconnected by means of mechanical and/or electric locking that their movements must 

succeed each other in proper sequence, train movements over all routes being governed by signal 

indication. 

§ 236.752 Joint, rail, insulated. 

 A joint in which electrical insulation is provided between adjoining rails. 

§ 236.753 Limits, interlocking. 

 The tracks between the opposing home signals of an interlocking. 

§ 236.754 Line, open wire. 

 An overhead wire line consisting of single conductors as opposed to multiple-conductor 

cables. 

§ 236.755 Link, rocker. 

 That portion of an interlocking machine which transmits motion between the latch and the 

universal link. 

§ 236.756 Lock, bolt. 

 A mechanical lock so arranged that if a switch, derail, or movable-point frog is not in the 

proper position for a train movement, the signal governing that movement cannot display an 

aspect to proceed; and that will prevent a movement of the switch, derail, or movable-point frog 

unless the signal displays its most restrictive aspect. 

§ 236.757 Lock, electric. 

 A device to prevent or restrict the movement of a lever, a switch, or a movable bridge, unless 

the locking member is withdrawn by an electrical device, such as an electromagnet, solenoid, or 

motor. 

§ 236.758 Lock, electric, forced-drop. 

 An electric lock in which the locking member is mechanically forced down to the locked 

position. 

§ 236.759 Lock, facing-point. 

 A mechanical lock for a switch, derail, or movable-point frog, comprising a plunger stand 

and a plunger which engages a lock rod attached to the switch point to lock the operated unit. 
236-160 

§ 236.760 Locking, approach. 

 Electric locking effective while a train is approaching, within a specified distance, a signal 

displaying an aspect to proceed, and which prevents, until after the expiration of a predetermined 

time interval after such signal has been caused to display its most restrictive aspect, the 

movement of any interlocked or electrically-locked switch, movable-point frog, or derail in the 

route governed by the signal, and which prevents an aspect to proceed from being displayed for 

any conflicting route. 

§ 236.761 Locking, electric. 

 The combination of one or more electric locks and controlling circuits by means of which 

levers of an interlocking machine, or switches, or other units operated in connection with 

signaling and interlocking, are secured against operation under certain conditions. 

§ 236.762 Locking, indication. 

 Electric locking which prevents manipulation of levers that would result in an unsafe 

condition for a train movement if a signal, switch, or other operative unit fails to make a 

movement corresponding to that of its controlling lever, or which directly prevents the operation 

of a signal, switch, or other operative unit, in case another unit which should operate first fails to 

make the required movement. 

§ 236.763 Locking, latch-operated. 

 The mechanical locking of an interlocking machine which is actuated by means of the lever 

latch. 

§ 236.764 Locking, lever-operated. 

 The mechanical locking of an interlocking machine which is actuated by means of the lever. 

§ 236.765 Locking, mechanical. 

 An arrangement of locking bars, dogs, tappets, cross-locking and other apparatus by means 

of which interlocking is effected between the levers of an interlocking machine and so 

interconnected that their movements must succeed each other in a predetermined order. 

§ 236.766 Locking, movable bridge. 

 The rail locks, bridge locks, bolt locks, circuit controllers, and electric locks used in 

providing interlocking protection at a movable bridge. 

§ 236.767 Locking, route. 

 Electric locking, effective when a train passes a signal displaying an aspect for it to proceed, 

which prevents the movement of any switch, movable-point frog, or derail underneath or in 

advance of the train within the route entered. It may be so arranged that as a train clears a track 

section of the route, the locking affecting that section is released. 
236-161 

§ 236.768 Locking, time. 

 A method of locking, either mechanical or electrical, which, after a signal has been caused to 

display an aspect to proceed, prevents, until after the expiration of a predetermined time interval 

after such signal has been caused to display its most restrictive aspect, the operation of any 

interlocked or electrically-locked switch, movable-point frog, or derail in the route governed by 

that signal, and which prevents an aspect to proceed from being displayed for any conflicting 

route. 

§ 236.769 Locking, traffic. 

 Electric locking which prevents the manipulation of levers or other devices for changing the 

direction of traffic on a section of track while that section is occupied or while a signal displays 

an aspect for a movement to proceed into that section. 

§ 236.770 Locomotive. 

 A self-propelled unit of equipment which can be used in train service. 

§ 236.771 Machine, control. 

 An assemblage of manually-operated devices for controlling the functions of a traffic control 

system; it may include a track diagram with indication lights. 

§ 236.772 Machine, interlocking. 

 An assemblage of manually-operated levers or other devices for the control of signals, 

switches, or other units. 

 Cross Reference: Magnet, track, see § 236.744. 

§ 236.773 Movements, conflicting. 

 Movements over conflicting routes. 

§ 236.774 Movement, facing. 

 The movement of a train over the points of a switch which face in a direction opposite to that 

in which the train is moving. 

§ 236.775 Movement, switch-and-lock. 

 A device, the complete operation of which performs the three functions of unlocking, 

operating, and locking a switch, movable-point frog, or derail. 

§ 236.776 Movement, trailing. 

 The movement of a train over the points of a switch which face in the direction in which the 

train is moving. 
236-162 

§ 236.777 Operator, control. 

 An employee assigned to operate the control machine of a traffic control system. 

§ 236.778 Piece, driving. 

 A crank secured to a locking shaft by means of which horizontal movement is imparted to a 

longitudinal locking bar. 

§ 236.779 Plate, top. 

 A metal plate secured to a locking bracket to prevent the cross-locking from being forced out 

of the bracket. 

§ 236.780 Plunger, facing-point lock. 

 That part of a facing-point lock which secures the lock rod to the plunger stand when the 

switch is locked. 

§ 236.781 [Reserved] 

§ 236.782 Point, controlled. 

 A location where signals and/or other functions of a traffic control system are controlled 

from the control machine. 

§ 236.783 Point, stop indication. 

 As applied to an automatic train stop or train control system without the use of roadway 

signals, a point where a signal displaying an aspect requiring a stop would be located. 

§ 236.784 Position, deenergized. 

 The position assumed by the moving member of an electromagnetic device when the device 

is deprived of its operating current. 

§ 236.785 Position, false restrictive. 

 A position of a semaphore arm that is more restrictive than it should be. 

§ 236.786 Principle, closed circuit. 

 The principle of circuit design where a normally energized electric circuit which, on being 

interrupted or deenergized, will cause the controlled function to assume its most restrictive 

condition. 

§ 236.787 Protection, cross. 

 An arrangement to prevent the improper operation of a signal, switch, movable-point frog, or 

derail as the result of a cross in electrical circuits. 
236-163 

 Cross Reference: Ramp, see § 236.744. 

§ 236.787a Railroad. 

 Railroad means any form of non-highway ground transportation that runs on rails or 

electromagnetic guideways and any entity providing such transportation, including- 

 (a) Commuter or other short-haul railroad passenger service in a metropolitan or suburban 

area and commuter railroad service that was operated by the Consolidated Rail Corporation on 

January 1, 1979; and 

 (b) High speed ground transportation systems that connect metropolitan areas, without 

regard to whether those systems use new technologies not associated with traditional railroads; 

but does not include rapid transit operations in an urban area that are not connected to the general 

railroad system of transportation. 

 [70 FR 11052, March 07, 2005] 

§ 236.788 Receiver. 

 A device on a locomotive, so placed that it is in position to be influenced inductively or 

actuated by an automatic train stop, train control, or cab signal roadway element. 

§ 236.789 Relay, timing. 

 A relay which will not close its front contacts or open its back contacts, or both, until the 

expiration of a definite time interval after the relay has been energized. 

§ 236.790 Release, time. 

 A device used to prevent the operation of an operative unit until after the expiration of a 

predetermined time interval after the device has been actuated. 

§ 236.791 Release, value. 

 The electrical value at which the movable member of an electromagnetic device will move to 

its deenergized position. 

§ 236.792 Reservoir, equalizing. 

 An air reservoir connected with and adding volume to the top portion of the equalizing piston 

chamber of the automatic brake valve, to provide uniform service reductions in brake pipe 

pressure regardless of the length of the train. 

 Cross Reference: Rocker, see § 236.755. 

§ 236.793 Rod, lock. 

 A rod, attached to the front rod or lug of a switch, movable-point frog, or derail, through 

which a locking plunger may extend when the switch points or derail are in the normal or reverse 

position. 
236-164 

§ 236.794 Rod, up-and-down. 

 A rod used for connecting the semaphore arm to the operating mechanism of a signal. 

§ 236.795 Route. 

 The course or way which is, or is to be, traveled. 

§ 236.796 Routes, conflicting. 

 Two or more routes, opposing, converging, or intersecting, over which movements cannot be 

made simultaneously without possibility of collision. 

§ 236.797 Route, interlocked. 

 A route within interlocking limits. 

§ 236.798 Section, dead. 

 A section of track, either within a track circuit or between two track circuits, the rails of 

which are not part of a track circuit. 

§ 236.799 Section, fouling. 

 The section of track between the switch points and the clearance point in a turnout. 

§ 236.800 Sheet, locking. 

 A description in tabular form of the locking operations in an interlocking machine. 

§ 236.801 Shoe, latch. 

 The casting by means of which the latch rod and the latch block are held to a lever of a 

mechanical interlocking machine. 

§ 236.802 Shunt. 

 A by-path in an electrical circuit. 

§ 236.802a Siding. 

 An auxiliary track for meeting or passing trains. 

§ 236.803 Signal, approach. 

 A roadway signal used to govern the approach to another signal and if operative, so 

controlled that its indication furnishes advance information of the indication of the next signal. 
236-165 

§ 236.804 Signal, block. 

 A roadway signal operated either automatically or manually at the entrance to a block. 

§ 236.805 Signal, cab. 

 A signal located in engineman's compartment or cab, indicating a condition affecting the 

movement of a train and used in conjunction with interlocking signals and in conjunction with or 

in lieu of block signals. 

§ 236.806 Signal, home. 

 A roadway signal at the entrance to a route or block to govern trains in entering and using 

that route or block. 

§ 236.807 Signal, interlocking. 

 A roadway signal which governs movements into or within interlocking limits. 

§ 236.808 Signals, opposing. 

 Roadway signals which govern movements in opposite directions on the same track or route. 

§ 236.809 Signal, slotted mechanical. 

 A mechanically-operated signal with an electromagnetic device inserted in its operating 

connection to provide a means of controlling the signal electrically, as well as mechanically. 

§ 236.810 Spectacle, semaphore arm. 

 That part of a semaphore arm which holds the roundels and to which the blade is fastened. 

§ 236.811 Speed, medium. 

 A speed not exceeding 40 miles per hour. 

§ 236.812 Speed, restricted. 

 A speed that will permit stopping within one-half the range of vision, but not exceeding 20 

miles per hour. 

 [49 FR 3388, Jan. 26, 1984] 

§ 236.813 Speed, slow. 

 A speed not exceeding 20 miles per hour. 

§ 236.813a State, most restrictive. 

 The mode of an electric or electronic device that is equivalent to a track relay in its 

deenergized position. 
236-166 

 [49 FR 3388, Jan. 26, 1984] 

§ 236.814 Station, control. 

 The place where the control machine of a traffic control system is located. 

§ 236.815 Stop. 

 As applied to mechanical locking, a device secured to a locking bar to limit its movement. 

§ 236.816 Superiority of trains. 

 The precedence conferred upon one train over other trains by train order or by reason of its 

class or the direction of its movement. 

§ 236.817 Switch, electro-pneumatic. 

 A switch operated by an electro-pneumatic switch-and-lock movement. 

§ 236.818 Switch, facing-point. 

 A switch, the points of which face traffic approaching in the direction for which the track is 

signaled. 

§ 236.819 Switch, hand-operated. 

 A non-interlocked switch which can only be operated manually. 

§ 236.820 Switch, interlocked. 

 A switch within the interlocking limits the control of which is interlocked with other 

functions of the interlocking. 

§ 236.820a Switch, power-operated. 

 A switch operated by an electrically, hydraulically, or pneumatically driven switch-and-lock 

movement. 

 [49 FR 3388, Jan. 26, 1984] 

§ 236.821 Switch, sectionalizing. 

 A switch for disconnecting a section of a power line from the source of energy. 

§ 236.822 Switch, spring. 

 A switch equipped with a spring device which forces the points to their original position after 

being trailed through and holds them under spring compression. 
236-167 

§ 236.823 Switch, trailing-point. 

 A switch, the points of which face away from traffic approaching in the direction for which 

the track is signaled. 

§ 236.824 System, automatic block signal. 

 A block signal system wherein the use of each block is governed by an automatic block 

signal, cab signal, or both. 

§ 236.825 System, automatic train control. 

 A system so arranged that its operation will automatically result in the following: 

 (a) A full service application of the brakes which will continue either until the train is 

brought to a stop, or, under control of the engineman, its speed is reduced to a predetermined 

rate. 

 (b) When operating under a speed restriction, an application of the brakes when the speed of 

the train exceeds the predetermined rate and which will continue until the speed is reduced to 

that rate. 

§ 236.826 System, automatic train stop. 

 A system so arranged that its operation will automatically result in the application of the 

brakes until the train has been brought to a stop. 

§ 236.827 System, block signal. 

 A method of governing the movement of trains into or within one or more blocks by block 

signals or cab signals. 

§ 236.828 System, traffic control. 

 A block signal system under which train movements are authorized by block signals whose 

indications supersede the superiority of trains for both opposing and following movements on the 

same track. 

§ 236.829 Terminal, initial. 

 The starting point of a locomotive for a trip. 

§ 236.830 Time, acknowledging. 

 As applied to an intermittent automatic train stop system, a predetermined time within which 

an automatic brake application may be forestalled by means of the acknowledging device. 

§ 236.831 Time, delay. 

 As applied to an automatic train stop or train control system, the time which elapses after the 

onboard apparatus detects a more restrictive indication until the brakes start to apply. 

 [49 FR 3388, Jan. 26, 1984] 
236-168 

§ 236.831a Track, main. 

 A track, other than auxiliary track, extending through yards and between stations, upon 

which trains are operated by timetable or train orders, or both, or the use of which is governed by 

block signals. 

§ 236.832 Train. 

 A locomotive or more than one locomotive coupled, with or without cars. 

§ 236.833 Train, opposing. 

 A train, the movement of which is in a direction opposite to and toward another train on the 

same track or route. 

§ 236.834 Trip. 

 A movement of a locomotive over all or any portion of automatic train stop, train control, or 

cab signal territory between the terminals for that locomotive; a movement in one direction. 

 Cross Reference: Trip-arm, see § 236.744. 

§ 236.835 Trunking. 

 A casing used to protect electrical conductors. 

§ 236.836 Trunnion. 

 A cylindrical projection supporting a revolving part. 

§ 236.837 Valve, electro-pneumatic. 

 A valve electrically-operated which, when operated, will permit or prevent passage of air. 

§ 236.838 Wire, shunt. 

 A wire forming part of a switch shunt circuit. 

Application:

The definitions contained within Subpart G are provided in order to gain understanding of the 

proper application of the various regulations within Part 236 that utilize the terms defined. 

Frequent reference to these definitions is therefore of significant importance to the uniform 

application of the regulations. 
236-169 

Subpart H – Standards for Processor-Based Signal and Train Control Systems

§ 236.901 Purpose and scope. 

 (a) What is the purpose of this subpart? The purpose of this subpart is to promote the safe 

operation of processor-based signal and train control systems, subsystems, and components that 

are safety-critical products, as defined in § 236.903, and to facilitate the development of those 

products. 

 (b) What topics does it cover? This subpart prescribes minimum, performance-based safety 

standards for safety-critical products, including requirements to ensure that the development, 

installation, implementation, inspection, testing, operation, maintenance, repair, and modification 

of those products will achieve and maintain an acceptable level of safety. This subpart also 

prescribes standards to ensure that personnel working with safety-critical products receive 

appropriate training. Each railroad may prescribe additional or more stringent rules, and other 

special instructions, that are not inconsistent with this subpart. 

 (c) What other rules apply? (1) This subpart does not exempt a railroad from compliance 

with the requirements of Subparts A through G of this part, except to the extent a PSP explains to 

FRA Associate Administrator for Safety’s satisfaction the following: 

 (i) How the objectives of any such requirements are met by the product; 

 (ii) Why the objectives of any such requirements are not relevant to the product; or 

 (iii) How the requirement is satisfied using alternative means. (See § 236.907(a)(14)). 

 (2) Products subject to this subpart are also subject to applicable requirements of 

Parts 233, 234, and 235 of this chapter. See § 234.275 of this chapter with respect to use of this 

subpart to qualify certain products for use within highway-rail grade crossing warning systems. 

 (3) Information required to be submitted by this subpart that a submitter deems to be trade 

secrets, or commercial or financial information that is privileged or confidential under 

Exemption 4 of the Freedom of Information Act, 5 U.S.C. 552(b)(4), shall be so labeled in 

accordance with the provisions of § 209.11 of this chapter. FRA handles information so labeled 

in accordance with the provisions of § 209.11 of this chapter. 

Application: 

This section does not require any field enforcement. The critical element for field personnel is 

Subpart H compliance may or may not relieve the railroad from compliance with other 

regulatory requirements. 

Inspectors must become familiar with the specific regulatory requirements for the product, 

contained within the product’s PSP, and evaluate regulatory compliance accordingly. 

§ 236.903 Definitions. 

 As used in this subpart -- 

 Associate Administrator for Safety means the Associate Administrator for Railroad Safety, 

FRA, or that person’s delegate as designated in writing.

Component means an element, device, or appliance (including those whose nature is 

electrical, mechanical, hardware, or software) that is part of a system or subsystem. 

Configuration management control plan means a plan designed to ensure that the proper and 

intended product configuration, including the hardware components and software version, is 

documented and maintained through the lifecycle of the products in use. 
236-170 

Employer means a railroad, or contractor to a railroad, that directly engages or compensates 

individuals to perform the duties specified in § 236.921(a). 

Executive software means software common to all installations of a given product. It 

generally is used to schedule the execution of the site-specific application programs, run timers, 

read inputs, drive outputs, perform self-diagnostics, access and check memory, and monitor the 

execution of the application software to detect unsolicited changes in outputs. 

FRA means the Federal Railroad Administration. 

Full automatic operation means that mode of an automatic train control system capable of 

operating without external human influence, in which the locomotive engineer or operator may 

act as a passive system monitor, in addition to an active system controller. 

Hazard means an existing or potential condition that can result in an accident. 

High degree of confidence, as applied to the highest level of aggregation, means there exists 

credible safety analysis supporting the conclusion that the likelihood of the proposed condition 

associated with the new product being less safe than the previous condition is very small. 

Human factors refers to a body of knowledge about human limitations, human abilities, and 

other human characteristics, such as behavior and motivation, that must be considered in product 

design. 

Human-machine interface (HMI) means the interrelated set of controls and displays that 

allows humans to interact with the machine. 

Initialization refers to the startup process when it is determined that a product has all required 

data input and the product is prepared to function as intended. 

Mandatory directive has the meaning set forth in § 220.5 of this chapter. 

Materials handling refers to explicit instructions for handling safety-critical components 

established to comply with procedures specified in the PSP. 

Mean Time to Hazardous Event (MTTHE) means the average or expected time that a 

subsystem or component will operate prior to the occurrence of an unsafe failure. 

New or next-generation train control system means a train control system using technologies 

not in use in revenue service at the time of PSP submission or without established histories of 

safe practice. 

Petition for approval means a petition to FRA for approval to use a product on a railroad as 

described in its PSP. The petition for approval is to contain information that is relevant to 

determining the safety of the resulting system; relevant to determining compliance with this part; 

and relevant to determining the safety of the product, including a complete copy of the product’s 

PSP and supporting safety analysis. 

Predefined change means any post-implementation modification to the use of a product that 

is provided for in the PSP (see § 236.907(b)). 

Previous condition refers to the estimated risk inherent in the portion of the existing method 

of operation that is relevant to the change under analysis (including the elements of any existing 

signal or train control system relevant to the review of the product). 

Processor-based, as used in this subpart, means dependent on a digital processor for its 

proper functioning. 

Product means a processor-based signal or train control system, subsystem, or component. 

Product Safety Plan (or PSP) refers to a formal document that describes in detail all of the 

safety aspects of the product, including, but not limited to, procedures for its development, 

installation, implementation, operation, maintenance, repair, inspection, testing and modification, 

as well as analyses supporting its safety claims, as described in 

§ 236.907. 
236-171 

Railroad Safety Program Plan (or RSPP) refers to a formal document that describes a 

railroad’s strategy for addressing safety hazards associated with operation of products under this 

subpart and its program for execution of such strategy through the use of PSP requirements, as 

described in § 236.905. 

Revision control means a chain-of-custody regimen designed to positively identify safetycritical components and spare equipment availability, including repair and replacement tracking 

in accordance with procedures outlined in the PSP. 

Risk means the expected probability of occurrence for an individual accident event 

(probability) multiplied by the severity of the expected consequences associated with the 

accident (severity). 

 Risk assessment means the process of determining, either quantitatively or qualitatively, the 

measure of risk associated with use of the product under all intended operating conditions or the 

previous condition. 

Safety-critical, as applied to a function, a system, or any portion thereof, means the correct 

performance of which is essential to safety of personnel or equipment, or both; or the incorrect 

performance of which could cause a hazardous condition, or allow a hazardous condition which 

was intended to be prevented by the function or system to exist. 

Subsystem means a defined portion of a system. 

System refers to a signal or train control system and includes all subsystems and components 

thereof, as the context requires. 

 System Safety Precedence means the order of precedence in which methods used to eliminate 

or control identified hazards within a system are implemented. 

Validation means the process of determining whether a product’s design requirements fulfill 

its intended design objectives during its development and lifecycle. The goal of the validation 

process is to determine “whether the correct product was built.” 

 Verification means the process of determining whether the results of a given phase of the 

development cycle fulfill the validated requirements established at the start of that phase. The 

goal of the verification process is to determine “whether the product was built correctly.” 

Application: 

This section does not require any field enforcement. Inspectors should be fully conversant with 

the above definitions, those contained in Subparts A through G, and those contained in AREMA 

Communications and Signal Manual, Section 17, which is incorporated into Subpart H at § 

236.909(d)(i). Inspectors should assure that in discussions with railroads and vendors, the use of 

these definitions have the same meaning among all parties. 

§ 236.905 Railroad Safety Program Plan. 

 (a) What is the purpose of an RSPP? A railroad subject to this subpart shall develop an 

RSPP, subject to FRA approval, that serves as its principal safety document for all safety-critical 

products. The RSPP must establish the minimum PSP requirements that will govern the 

development and implementation of all products subject to this subpart, consistent with the 

provisions contained in § 236.907.

 (b) What subject areas must the RSPP address? The railroad’s RSPP must address, at a 

minimum, the following subject areas: 

 (1) Requirements and concepts. The RSPP must require a description of the preliminary 

safety analysis, including: 

 (i) A complete description of methods used to evaluate a system’s behavioral characteristics; 

 (ii) A complete description of risk assessment procedures; 
236-172 

 (iii) The system safety precedence followed; and 

 (iv) The identification of the safety assessment process. 

 (2) Design for verification and validation. The RSPP must require the identification of 

verification and validation methods for the preliminary safety analysis, initial development 

process, and future incremental changes, including standards to be used in the verification and 

validation process, consistent with Appendix C to this part. The RSPP must require that 

references to any non-published standards be included in the PSP. 

 (3) Design for human factors. The RSPP must require a description of the process used 

during product development to identify human factors issues and develop design requirements 

which address those issues. 

 (4) Configuration management control plan. The RSPP must specify requirements for 

configuration management for all products to which this subpart applies. 

 (c) How are RSPPs approved? (1) Each railroad is required to submit a petition for approval 

of an RSPP in triplicate to the Associate Administrator for Railroad Safety, FRA, 1200 New 

Jersey Avenue, SE., Mail Stop 25, Washington, DC 20590. The petition must contain a copy of 

the proposed RSPP, and the name, title, address, and telephone number of the railroad’s primary 

contact person for review of the petition. 

 (2) Normally within 180 days of receipt of a petition for approval of an RSPP, FRA: 

 (i) Grants the petition, if FRA finds that the petition complies with applicable requirements 

of this subpart, attaching any special conditions to the approval of the petition as necessary to 

carry out the requirements of this subpart; 

 (ii) Denies the petition, setting forth reasons for denial; or 

 (iii) Requests additional information. 

 (3) If no action is taken on the petition within 180 days, the petition remains pending for 

decision. The petitioner is encouraged to contact FRA for information concerning its status. 

 (4) FRA may reopen consideration of any previously-approved petition for cause, providing 

reasons for such action. 

 (d) How are RSPP’s modified? (1) Railroads shall obtain FRA approval for any modification 

to their RSPP which affects a safety-critical requirement of a PSP. Other modifications do not 

require FRA approval. 

 (2) Petitions for FRA approval of RSPP modifications are subject to the same procedures as 

petitions for initial RSPP approval, as specified in paragraph (c) of this section. In addition, such 

petitions must identify the proposed modification(s) to be made, the reason for the 

modification(s), and the effect of the modification(s) on safety. 

Application: 

The RSPP is the overall safety plan for the implementation of new or novel processor-based 

signal and train control systems on the railroad. It is intended to be a living document. 

Headquarters’ technical staff will review RSPPs and petitions for modifications of RSPPs for 

sufficiency, and prepare recommendations for approval, conditional approval, or denial. Once 

approved, close coordination between the headquarters and field staff will be required to ensure 

that the document is properly maintained and utilized by the railroad. 

Inspectors must be familiar with their railroad’s approved RSPP and the associated processorbased signal or train control systems that it covers. It is a violation if a safety-critical change to a 

railroad’s RSPP is discovered and FRA has not approved it. While other modifications do not 

require FRA approval and are not violations, failure of a railroad to modify their RSPP when 

there is such a change required is a violation. It is also a violation where new or novel processor- 
236-173 

based signal or train control systems are found to have been deployed and (1) the railroad does 

not have an approved RSPP or (2) an approved RSPP exists, but the RSPP does not reflect the 

new product. 

CLASSIFICATION OF DEFECTS 

236.905.A1 Failure to develop RSPP when required. 

236.905.B1 Failure to address minimum required RSPP subject areas. 

236.905.C1 Failure to submit RSPP when required. 

236.905.D1 Failure to obtain FRA approval for a modification to the RSPP. 

§ 236.907 Product Safety Plan. 

 (a) What must a PSP contain? The PSP must include the following: 

 (1) A complete description of the product, including a list of all product components and 

their physical relationship in the subsystem or system;

 (2) A description of the railroad operation or categories of operations on which the product is 

designed to be used, including train movement density, gross tonnage, passenger train movement 

density, hazardous materials volume, railroad operating rules, and operating speeds; 

 (3) An operational concepts document, including a complete description of the product 

functionality and information flows; 

 (4) A safety requirements document, including a list with complete descriptions of all 

functions that the product performs to enhance or preserve safety; 

 (5) A document describing the manner in which product architecture satisfies safety 

requirements; 

 (6) A hazard log consisting of a comprehensive description of all safety-relevant hazards to 

be addressed during the lifecycle of the product, including maximum threshold limits for each 

hazard (for unidentified hazards, the threshold shall be exceeded at one occurrence); 

 (7) A risk assessment, as prescribed in § 236.909 and Appendix B to this part; 

 (8) A hazard mitigation analysis, including a complete and comprehensive description of all 

hazards to be addressed in the system design and development, mitigation techniques used, and 

system safety precedence followed, as prescribed by the applicable RSPP; 

 (9) A complete description of the safety assessment and verification and validation processes 

applied to the product and the results of these processes, describing how subject areas covered in 

Appendix C to this part are either addressed directly, addressed using other safety criteria, or not 

applicable;

 (10) A complete description of the safety assurance concepts used in the product design, 

including an explanation of the design principles and assumptions; 

 (11) A human factors analysis, including a complete description of all human-machine 

interfaces, a complete description of all functions performed by humans in connection with the 

product to enhance or preserve safety, and an analysis in accordance with Appendix E to this part 

or in accordance with other criteria if demonstrated to the satisfaction of the Associate 

Administrator for Railroad Safety to be equally suitable; 

 (12) A complete description of the specific training of railroad and contractor employees and 

supervisors necessary to ensure the safe and proper installation, implementation, operation, 

maintenance, repair, inspection, testing, and modification of the product; 
236-174 

 (13) A complete description of the specific procedures and test equipment necessary to 

ensure the safe and proper installation, implementation, operation, maintenance, repair, 

inspection, testing, and modification of the product. These procedures, including calibration 

requirements, shall be consistent with or explain deviations from the equipment manufacturer’s 

recommendations; 

 (14) An analysis of the applicability of the requirements of Subparts A through G of this part 

to the product that may no longer apply or are satisfied by the product using an alternative 

method, and a complete explanation of the manner in which those requirements are otherwise 

fulfilled (see § 234.275 of this chapter and § 236.901(c)); 

 (15) A complete description of the necessary security measures for the product over its 

lifecycle; 

 (16) A complete description of each warning to be placed in the Operations and Maintenance 

Manual identified in § 236.919, and of all warning labels required to be placed on equipment as 

necessary to ensure safety; 

 (17) A complete description of all initial implementation testing procedures necessary to 

establish that safety-functional requirements are met and safety-critical hazards are appropriately 

mitigated; 

 (18) A complete description of: 

 (i) all post-implementation testing (validation) and monitoring procedures, including the 

intervals necessary to establish that safety-functional requirements, safety-critical hazard 

mitigation processes, and safety-critical tolerances are not compromised over time, through use, 

or after maintenance (repair, replacement, adjustment) is performed; and 

 (ii) Each record necessary to ensure the safety of the system that is associated with periodic 

maintenance, inspections, tests, repairs, replacements, adjustments, and the system’s resulting 

conditions, including records of component failures resulting in safety-relevant hazards (See § 

236.917); 

 (19) A complete description of any safety-critical assumptions regarding availability of the 

product, and a complete description of all backup methods of operation; and 

 (20) A complete description of all incremental and predefined changes (See paragraphs (b) 

and (c) of this section). 

 (b) What requirements apply to predefined changes? (1) Predefined changes are not 

considered design modifications requiring an entirely new safety verification process, a revised 

PSP, and an Informational 

Filing or petition for approval in accordance with § 236.915. However, the risk assessment for 

the product must demonstrate that operation of the product, as modified by any predefined 

change, satisfies the minimum performance standard. 

 (2) The PSP must identify configuration/revision control measures designed to ensure that 

safety-functional requirements and safety-critical hazard mitigation processes are not 

compromised as a result of any such change. (Software changes involving safety functional 

requirements or safety critical hazard mitigation processes for components in use are also 

addressed in paragraph (c) of this section.) 

 (c) What requirements apply to other product changes? (1) Incremental changes are planned 

product version changes described in the initial PSP where slightly different specifications are 

used to allow the gradual enhancement of the product’s capabilities. Incremental changes shall 

require verification and validation to the extent the changes involve safety-critical functions. 

 (2) Changes classified as maintenance require validation. 

 (d) What are the responsibilities of the railroad and product supplier regarding 

communication of hazards? (1) The PSP shall specify all contractual arrangements with 

hardware and software suppliers for immediate notification of any and all safety critical software 
236-175 

upgrades, patches, or revisions for their processor-based system, subsystem, or component, and 

the reasons for such changes from the suppliers, whether or not the railroad has experienced a 

failure of that safety-critical system, subsystem, or component. 

 (2) The PSP shall specify the railroad’s procedures for action upon notification of a safetycritical upgrade, patch, or revision for this processor-based system, subsystem, or component, 

and until the upgrade, patch, or revision has been installed; and such action shall be consistent 

with the criterion set forth in § 236.915(d) as if the failure had occurred on that railroad. 

 (3) The PSP must identify configuration/revision control measures designed to ensure that 

safety-functional requirements and safety-critical hazard mitigation processes are not 

compromised as a result of any such change, and that any such change can be audited. 

 (4) Product suppliers entering into contractual arrangements for product support described in 

a PSP must promptly report any safety-relevant failures and previously unidentified hazards to 

each railroad using the product. 

Application: 

Enforcement of this section is two-phased. The first phase does not normally involve field 

personnel but rather is accomplished by headquarters staff. This phase involves extensive review 

of the PSP for completeness and sufficiency, and demonstration that the required performance 

standard presented can be met. Headquarters staff will define the basic internal FRA review 

cycle and key functional roles and responsibilities of reviewers. This ensures that accountability 

for the timely review of the PSP is maintained throughout the review process, and that the PSP 

remain an effective tool in managing risks and maintaining public safety. Field personnel 

involvement during this phase is on a case-by-case basis. Unsatisfactory compliance to the 

requirements by the railroads during the approval process phase is not considered noncompliance 

with the regulation but rather, if remaining unresolved while working through the review process 

with the railroad, possible grounds for nonapproval. 

The second phase requires significant field personnel involvement to ensure that the railroad is in 

compliance with the approved PSP once the product is in revenue service, and to advise 

headquarters of noncompliance with the terms and conditions associated with FRA’s approval. 

Upon implementation of a product, certain PSP requirements are to be properly maintained 

throughout the lifecycle of the product to ensure safety of train operations is not impaired 

through product use, modification, or maintenance issues. 

It is important for field personnel to understand, and accept, that the safety assessment done by 

headquarters will not prove that a product is absolutely safe. It only provides evidence that risks 

associated with the product have been carefully considered and that steps have been taken to 

eliminate or mitigate them. Hazards associated with product use are identified during the 

approval phase, and hazard analysis methods are employed to identify, eliminate, and mitigate 

hazards. It is highly important however that the railroad operates and maintains the system or 

product in the manner identified within the PSP. That is the principle that the field personnel 

will be most involved in. 

Paragraph (a)(6) requires that a hazard log be included in the PSP. This log consists of a 

comprehensive description of all hazards to be addressed during the lifecycle of the product, 

including maximum threshold limits for each hazard (for unidentified hazards, the threshold shall 

be exceeded at one occurrence). The hazard log addresses safety-relevant hazards, or incidents 

and failures that affect the safety and risk assumptions of the product. Safety-relevant hazards 
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include events such as false proceed signal indications, failure to enforce speeds or stop where a 

stop is required, unexpected or sudden brake applications, and false restrictive signal indications. 

If false restrictive signal indications happen with any type of frequency, they could cause train 

crewmembers or other users (roadway workers, dispatchers, etc.) to develop a lackadaisical 

attitude towards complying with signal indications or instructions from the product, creating 

human factors problems. Incidents in which stop indications are inappropriately displayed may 

also necessitate sudden brake applications that may involve risk of derailment due to in-train 

forces. Other unsafe or wrong-side failures that affect the safety of the product must be recorded 

on the hazard log. 

The intent of this requirement is to identify all possible safety-relevant hazards that would have a 

negative effect on the safety of the product, including derived hazards, e.g., hardware and 

software hazards introduced by the technology employed and all known hazards are identified 

and logged. Field inspectors should become familiar with the hazards identified, and accepted, 

so that they can recognize any new, previously undefined hazards that may arise during system 

operations and report them. Any single occurrence of a hazard that would have a negative 

impact on safety not previously identified is of serious concern, and the inspector should report it 

immediately to headquarters through their appropriate chain of command. 

Paragraph (a)(12) requires the railroad to include in its PSP the training, qualification, and 

designation program for workers (railroad or non-railroad employees) who will perform 

inspection, testing, and maintenance tasks involving the product. FRA believes many benefits 

accrue from the investment in comprehensive training programs. which, among other things, are 

fundamental to creating a safe workforce. Effective training programs can result in fewer 

instances of human casualties and defective equipment, leading to increased operating 

efficiencies, less troubleshooting, and decreased costs. Where systems are implemented into 

revenue service, inspectors shall monitor the associated training program to ensure it is kept 

current and in compliance with the requirements set forth in the PSP. 

 

Paragraph (a)(13) requires the PSP to identify specific procedures and test equipment necessary 

to ensure the safe operation, installation, repair, modification, and testing of the product. 

Requirements for operation of the system must be succinct in every respect. The procedures 

must be specific about the methodology to be employed for each test to be performed that is 

required for installation, repair, or modification; including documenting the results thereof. 

Where a product is placed in revenue service, inspectors shall monitor these procedures to ensure 

the product is properly installed, maintained, and tested. 

 

Paragraph (a)(14) provides that products may be so designed that existing requirements 

contained in Part 236, Subparts A, B, C, D, E, and F may not be applicable. In this event, the 

PSP must identify each pertinent requirement considered to be inapplicable, fully describe the 

alternative method used that equates to that requirement, and explain how the alternative method 

fulfills or exceeds the provisions of the requirement. Certain sections of Part 236 may always be 

applicable to Subpart H products. For example, § 236.0 prescribes, among other requirements, 

the conditions and speeds for which block signal systems and automatic cab signal, train stop, 

and train control systems must be installed. These are benchmark safety levels related to 

operational considerations against which the safety performance of innovative newer systems 

will be compared. Inspectors must be familiar with what provisions have been waived, and what 

provisions have not. They should enforce those provisions of Part 236, Subparts A through G 

that have not been waived. 
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Paragraph (a)(15) requires the PSP to include a description of the security measures necessary to 

meet the specifications for each product. Security is an important element in the design and 

development of products and covers issues such as developing measures to prevent hackers from 

gaining access to software and developing measures to preclude sudden system shutdown. FRA 

inspectors should ensure that the approved security mechanisms are used by the railroad. Failure 

to use the approved security mechanism should be considered a violation. 

 

Paragraph (a)(16) requires warnings to ensure safety is addressed in the Operations and 

Maintenance Manual and warning labels placed on the equipment of each product as necessary. 

Such warnings include, but are not limited to, means to prevent unauthorized access to the 

system; warnings of electrical shock hazards; cautionary notices about improper usage, testing, 

or operation; and configuration 

management of memory and databases. Where a product is placed in revenue service, inspectors 

shall monitor warnings to ensure they are kept current in the Operations and Maintenance 

Manual and warning labels are maintained as required. 

Paragraph (a)(17) requires the railroad to develop comprehensive plans and procedures for 

product implementation. Implementation (validation or cutover) procedures must be prepared in 

detail and identify the processes necessary to verify the product is properly installed and 

documented, including measures to provide for the safety of train operations during installation. 

Test procedures identify the functionality to be tested, methodology to be used to perform the 

test, and contain pass/fail criteria. Once approved as part of the PSP, inspectors should review 

operating rules, any imposed conditions, and the cutover procedures to ensure railroad 

compliance during field tests or cutovers to assure safety of train operations are not impaired. 

The railroads’ noncompliance with the requirement to use approved procedures, or failure to 

comply with them, is a violation. 

Paragraph (a)(18)(i) requires the railroad to provide a complete description of the particulars 

concerning measures required to assure products, once implemented, continue to provide the 

expected safety level without degradation or variation over their lifecycle. The measures must 

be specific regarding prescribed intervals and criteria for testing; scheduled preventive 

maintenance requirements; procedures for configuration management; and procedures for 

modifications, repair, replacement, and adjustment of equipment. Inspectors will use this 

information, among other data, to monitor a product placed in service to assure it continues to 

function as intended. Failure of the railroad to comply with these measures is a violation. 

Paragraph (a)(18)(ii) provides a PSP requirement to include a description of each record 

concerning safe operation. The description is required to identify each record necessary to 

ensure the safety of the system that is associated with periodic maintenance, inspections, tests, 

repairs, replacements, adjustments, and the system’s resulting conditions, including records of 

component failures resulting in safety-relevant hazards (see § 236.917). Inspectors will monitor 

the records of test results of systems placed in service to assure they are properly maintained, 

inspected, and tested. Failure of the railroad to do so is a violation. 

Paragraph (a)(19) requires that the PSP include a description of all backup methods of operation 

and safety-critical assumptions regarding availability of the product. FRA believes this 

information is essential for making determinations about the safety of a product and both the 

immediate and long term affect of its failure. It is a prerequisite of this rule that the safetycritical assumptions regarding availability of the product must be identified in the PSP. 

Availability is directly related to safety to the extent the backup means of controlling operations 
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involves greater risk (either inherently or because it is infrequently practiced). Further, it is 

required that the PSP describe all backup methods of operation in the event of product failure or 

removal from service. Inspectors are to ensure that the backup methods of operation, and their 

associated procedures, are followed by the railroad. Failure of the railroad to do so is a violation. 

Paragraph (a)(20) requires that the PSP include a complete description of all incremental and 

predefined changes. Predefined change means any post-implementation modification to the use 

of a product that is provided for in the PSP. (See § 236.903 Definitions) 

Paragraph (b)(1) addresses predefined changes. PSPs identify the various configurable 

applications of 

the product, since this rule mandates use of the product only in the manner described in its PSP 

(see 

§ 236.915(d)). Also, the PSP must fully describe the procedures to be followed for each change 

and the inspections and tests necessary to assure the system functions as intended. Inspectors 

will monitor systems placed in service to ensure the product is implemented and maintained only 

in the manner described in the PSP. 

Paragraph (c)(1) addresses the conditions associated with incremental and maintenance changes 

and with changes classified as safety-critical software upgrades, patches, or revisions. The term 

“incremental change” is intended to capture the concept of planned version changes to a product, 

usually software-type changes. These changes will be necessary in order for products to acquire 

capabilities to perform added functions as safety requirements change. This requirement is 

intended to encourage as many subsequent product modifications (as possible) to be considered 

by initial designers during the product development stage, in order to avoid, to the extent 

possible, changes made by persons with no link to initial safety design considerations. These 

changes may be undertaken by a railroad if approved as part of the PSP. Inspectors should be 

familiar with the approved incremental changes and alert for the implementation of nonapproved changes. Railroads implementing non-approved incremental changes without 

submission and approval of a revised PSP are in violation of the approval conditions of their 

PSP. 

Paragraph (c)(2) clarifies that incremental changes classified as maintenance also require 

validation. The inspector should ensure that these changes are validated, and that the railroad is 

following approved processes and procedures identified in the PSP. Railroads not doing so are 

in violation of the approval conditions of their PSP. 

Paragraph (d)(1) sets forth the responsibilities of the railroad and product supplier regarding the 

communication of hazards. Railroads are required to specify the contractual arrangements with 

hardware and software suppliers for immediate notification of any safety-critical problems 

associated with the product. Hardware and software suppliers are in the best position to know 

about problems with the products used by the railroads. Suppliers likely have information 

regarding problems with their products. Given the importance of proper configuration 

management in safety-critical systems, it is essential that railroads learn of and take appropriate 

action to address all safety-critical software upgrades, patches, or revisions for their processorbased system, subsystem, or component, whether or not the railroads have experienced a specific 

failure of their system, subsystem, or component. 
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Railroads are required to either develop a mutually acceptable external contractual relationship 

with software developers capable of providing the required timely software support, or to 

demonstrate they have in-house software development capability to provide the necessary 

support. This support shall include providing the necessary safety software upgrade, patch, or 

revisions after determination of a need, identification of the specific product and software 

version involved, the nature of the risk, any recommended mitigation pending assurance of the 

corrected software, and any necessary regression testing. Lack of such a fundamental lifecycle 

software support capability calls into question the long term suitability of the software for safetycritical operations. Similar concerns apply to specialized hardware. Railroads are also required 

to develop a mutually acceptable external contractual relationship with developers of specialized 

hardware capable of providing the required timely software support. 

Where systems are placed in service, inspectors will ensure the configuration/revision control 

measures are kept current, reflect each change in hardware and/or software, and can be audited. 

Inspectors shall monitor systems placed in service to ensure such contractual arrangements 

remain in place throughout the 

life-cycle of the product. Where it is found that no such arrangement exists, inspectors shall 

immediately report the circumstances to headquarters staff. 

Paragraph (d)(2) requires the railroad to specify procedures to be followed upon notification by a 

supplier of a safety-critical problem. Upon such notification and provision of software changes 

by a supplier, the upgrade, patch, or revision must be installed without undue delay. Until the 

software upgrade, patch, or revision has been installed, a railroad must treat the product as if a 

safety-critical hazard exists and take the appropriate action specified in the PSP and by the 

supplier. This requirement is necessary to ensure that any needed component changes that would 

increase risk or interfere with the safety of train operations, if left uncorrected, are promptly 

addressed and that a common safety baseline is maintained. Similar action is required where 

suppliers of hardware provide notification and provision of hardware modifications. Inspectors 

should monitor systems placed in service to ensure railroad procedures remain in force, are 

invoked as necessary, and that necessary modifications are made without undue delay. 

Paragraph (d)(3) requires railroads to identify configuration/revision control measures designed 

to ensure that safety-functional requirements and safety-critical hazard mitigation processes are 

not compromised as a result of changes made following notification by suppliers. Not all 

railroads may experience the same software faults or hardware failures. The developer’s 

software development, configuration management, and fault reporting tracking system play a 

crucial role in the ability of the railroad and the FRA to be able to determine and fully understand 

the risks and their implications. Without an effective configuration management tracking system 

in place, it is difficult, if not impossible, to fairly evaluate risks associated with a product over 

the life of the product. Inspectors will monitor systems placed in service to ensure the approved 

configuration/revision control measures are put into effect and properly maintained. 

Paragraph (d)(4) addresses the responsibilities of product suppliers. This requirement places a 

direct obligation on suppliers to report safety-relevant failures, which would include “wrongside” failures and failures significantly impacting on availability where the PSP indicates 

availability to be a material issue in the safety performance of the larger railroad system. 

Suppliers take on this responsibility under contract to the railroad as disclosed in the PSP. 

Inspectors shall monitor systems placed in service to ensure suppliers provide immediate 

notification of needed hardware and software changes to railroads using their products. Where it 
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is found a product supplier has not done so, or the product developer is no longer in business or 

is unwilling to support the product, headquarters staff shall be promptly notified of the 

circumstances surrounding the failure to perform. 

CLASSIFICATION OF DEFECTS 

236.907.A1 Failure to address required PSP elements. 

236.907.B1 Failure to identify or implement product configuration/revision control measures. 

236.905.D1 Failure to communicate identified safety-critical hazards. 

§ 236.909 Minimum performance standard. 

 (a) What is the minimum performance standard for products covered by this subpart? The 

safety analysis included in the railroad’s PSP must establish with a high degree of confidence 

that introduction of the product will not result in risk that exceeds the previous condition. The 

railroad shall determine, prior to filing its petition for approval or informational filing, that this 

standard has been met and shall make available the necessary analyses and documentation as 

provided in this subpart. 

 (b) How does FRA determine whether the PSP requirements for products covered by subpart 

H have been met? With respect to any FRA review of a PSP, the Associate Administrator for 

Railroad Safety independently determines whether the railroad’s safety case establishes with a 

high degree of confidence that introduction of the product will not result in risk that exceeds the 

previous condition. In evaluating the sufficiency of the railroad’s case for the product, the 

Associate Administrator for Railroad Safety considers, as applicable, the factors pertinent to 

evaluation of risk assessments, listed in § 236.913(g)(2). 

 (c) What is the scope of a full risk assessment required by this section? A full risk 

assessment performed under this subpart must address the safety risks affected by the 

introduction, modification, replacement, or enhancement of a product. This includes risks 

associated with the previous condition which are no longer present as a result of the change, new 

risks not present in the previous condition, and risks neither newly created nor eliminated whose 

nature (probability of occurrence or severity) is nonetheless affected by the change. 

 (d) What is an abbreviated risk assessment, and when may it be used? (1) An abbreviated 

risk assessment may be used in lieu of a full risk assessment to show compliance with the 

performance standard if: 

 (i) No new hazards are introduced as a result of the change; 

 (ii) Severity of each hazard associated with the previous condition does not increase from the 

previous condition; and 

 (iii) Exposure to such hazards does not change from the previous condition. 

 (2) An abbreviated risk assessment supports the finding required by paragraph (a) of this 

section if it establishes that the resulting MTTHE for the proposed product is greater than or 

equal to the MTTHE for the system, component, or method performing the same function in the 

previous condition. This determination must be supported by credible safety analysis sufficient 

to persuade the Associate Administrator for Railroad Safety that the likelihood of the new 

product’s MTTHE being less than the MTTHE for the system, component, or method 

performing the same function in the previous condition is very small. 

 (3) Alternatively, an abbreviated risk assessment supports the finding required by paragraph 

(a) of this section if: 
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 (i) The probability of failure for each hazard of the product is equal to or less than the 

corresponding recommended Specific Quantitative Hazard Probability Ratings classified as more 

favorable than “undesirable” by AREMA Manual Part 17.3.5 (Recommended Procedure for 

Hazard Identification and Management of Vital Electronic/Software-Based Equipment Used in 

Signal and Train Control Applications), or—in the case of a hazard classified as undesirable—

the Associate Administrator for Railroad Safety concurs that mitigation of the hazard within the 

framework of the electronic system is not practical and the railroad proposes reasonable steps to 

undertake other mitigation. The Director of the Federal Register approves the incorporation by 

reference of the entire AREMA Communications and Signal Manual, Volume 4, Section 17–

Quality Principles (2005) in this section in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 

You may obtain a copy of the incorporated standard from American Railway Engineering and 

Maintenance of Way Association, 8201 Corporation Drive, Suite 1125, Landover, MD 20785-

2230. You may inspect a copy of the incorporated standard at the Federal Railroad 

Administration, Docket Clerk, 1200 New Jersey Avenue, SE., Washington, DC 20590 or at the 

National Archives and Records Administration (NARA). For information on the availability of 

this material at NARA, call 202-741-6030, or go to 

http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html; 

 (ii) The product is developed in accordance with: 

 (A) AREMA Manual Part 17.3.1 (Communications and Signal Manual of Recommended 

Practices, Recommended Safety Assurance Program for Electronic/ Software Based Products 

Used in Vital Signal Applications); 

 (B) AREMA Manual Part 17.3.3 (Communications and Signal Manual of Recommended 

Practices, Recommended Practice for Hardware Analysis for Vital Electronic/Software-Based 

Equipment Used in Signal and Train Control Applications); 

 (C) AREMA Manual Part 17.3.5 (Communications and Signal Manual of Recommended 

Practices, Recommended Practice for Hazard Identification and Management of Vital 

Electronic/Software-Based Equipment Used in Signal and Train Control Applications); 

 (D) Appendix C of this subpart; and 

 (iii) Analysis supporting the PSP suggests no credible reason for believing that the product 

will be less safe than the previous condition. 

 (e) How are safety and risk measured for the full risk assessment? Risk assessment 

techniques, including both qualitative and quantitative methods, are recognized as providing 

credible and useful results for purposes of this section if they apply the following principles: 

 (1) Safety levels must be measured using competent risk assessment methods and must be 

expressed as the total residual risk in the system over its expected lifecycle after implementation 

of all mitigating measures described in the PSP. The total risk assessment must have a 

supporting sensitivity analysis. The analysis must confirm that the risk metrics of the system are 

not negatively affected by sensitivity analysis input parameters including, for example, 

component failure rates, human factor error rates, and variations in train traffic affecting 

exposure. In this context, “negatively affected” means that the final residual risk metric does not 

exceed that of the base case or that which has been otherwise established through MTTHE target. 

The sensitivity analysis must document the sensitivity to worst case failure scenarios. Appendix 

B to this part provides criteria for acceptable risk assessment methods. Other methods may be 

acceptable if demonstrated to the satisfaction of the Associate Administrator for Railroad Safety 

to be equally suitable. 

 (2) For the previous condition and for the lifecycle of the product, risk levels must be 

expressed in units of consequences per unit of exposure. 

 (i) In all cases exposure must be expressed as total train miles traveled per year over the 

relevant railroad infrastructure. Consequences must identify the total cost, including fatalities, 
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injuries, property damage, and other incidental costs, such as potential consequences of 

hazardous materials involvement, resulting from preventable accidents associated with the 

function(s) performed by the system. A railroad may, as an alternative, use a risk metric in 

which consequences are measured strictly in terms of fatalities. 

 (ii) In those cases where there is passenger traffic, a second risk metric must be calculated, 

using passenger-miles traveled per year as the exposure, and total societal costs of passenger 

injuries and fatalities, resulting from preventable accidents associated with the function(s) 

performed by the system, as the consequences. 

 (3) If the description of railroad operations for the product required by § 236.907(a)(2) 

involves changes to the physical or operating conditions on the railroad prior to or within the 

expected life-cycle of the product subject to review under this subpart, the previous condition 

shall be adjusted to reflect the lower risk associated with systems needed to maintain safety and 

performance at higher speeds or traffic volumes. In particular, the previous condition must be 

adjusted for assumed implementation of systems necessary to support higher train speeds as 

specified in § 236.0, as well as other changes required to support projected increases in train 

operations. The following specific requirements apply: 

 (i) If the current method of operation would not be adequate under § 236.0 for the proposed 

operations, then the adjusted previous condition must include a system as required under § 236.0, 

applied as follows: 

 (A) The minimum system where a passenger train is operated at a speed of 60 or more mph, 

or a freight train is operated at a speed of 50 or more mph, shall be a traffic control system; 

 (B) The minimum system where a train is operated at a speed of 80 or more mph, but not 

more than 110 mph, shall be an automatic cab signal system with automatic train control; and 

 (C) The minimum system where a train is operated at a speed of more than 110 mph shall be 

a system determined by the Associate Administrator for Railroad Safety to provide an equivalent 

level of safety to systems required or authorized by FRA for comparable operations. 

 (ii) If the current method of operation would be adequate under § 236.0 for the proposed 

operations, but the current system is not at least as safe as a traffic control system, then the 

adjusted previous condition must include a traffic control system in the event of any change that 

results in: 

 (A) An annual average daily train density of more than twelve trains per day; or 

 (B) An increase in the annual average daily density of passenger trains of more than four 

trains per day. 

 (iii) Subparagraph (e)(3)(ii)(A) of this section shall apply in all situations where train 

volume will exceed more than 20 trains per day but shall not apply to situations where train 

volume will exceed 12 trains per day but not exceed 20 trains per day, if in its PSP the railroad 

makes a showing sufficient to establish, in the judgment of the Associate Administrator for 

Safety, that the current method of operation is adequate for a specified volume of traffic in 

excess of 12 trains per day, but not more than 20 trains per day, without material delay in the 

movement of trains over the territory and without unreasonable expenditures to expedite those 

movements when compared with the expense of installing and maintaining a traffic control 

system. 

 (4) In the case review of a PSP that has been consolidated with a proceeding pursuant to part 

235 of this subchapter (see § 236.911(b)), the base case shall be determined as follows: 

 (i) If FRA determines that discontinuance or modification of the system should be granted 

without regard to whether the product is installed on the territory, then the base case shall be the 

conditions that would obtain on the territory following the discontinuance or modification. Note: 

This is an instance in which the base case is posited as greater risk than the actual (unadjusted) 

previous condition because the railroad would have obtained relief from the requirement to 

maintain the existing signal or train control system even if no new product had been proffered. 
236-183 

 (ii) If FRA determines that discontinuance or modification of the system should be denied 

without regard to whether the product is installed on the territory, then the base case shall remain 

the previous condition (unadjusted) 

 (iii) If, after consideration of the application and review of the PSP, FRA determines that 

neither paragraph (e)(4)(i) nor paragraph (e)(4)(ii) of this section should apply, FRA will 

establish a base case that is consistent with safety and in the public interest. 

Application: 

The purpose of the minimum performance standard is to establish the level of performance that 

must be achieved, but not how it must be achieved. The objective is to make certain that new or 

novel processor-based signal and train control systems are at least as safe as the systems they 

would replace. Headquarters personnel accomplish the majority of this section. Field 

involvement is generally limited to reevaluating compliance with the operational and traffic 

volume restrictions designated in the PSP. 

The railroad must establish with a high degree of confidence through its safety analysis that 

introduction of the system will not result in a safety risk level that exceeds the level of safety risk 

in the previous condition. High degree of confidence, as applied to the highest level of 

aggregation, means that there exists credible safety analysis supporting the conclusion that “the 

likelihood of the proposed condition associated with the new product being less safe than the 

previous condition is very small.” In short, the railroad must prove that safety is not degraded. 

This standard places the burden on the railroad to demonstrate that the safety analysis provides a 

high degree of confidence. 

Performance is evaluated as a comparison between the level of safety in the previous condition 

and the new or proposed condition. Previous condition refers to the estimated risk inherent in 

the portion of the existing method of operation (e.g., track warrant control, operation by signal 

indication of a traffic control system, etc.) that is relevant to the change under analysis, including 

the elements of any existing signal or train control system relevant to the review of the product. 

The exposure to the risk as related primarily to railroad operating practices (i.e., train speeds, 

train volumes, utilization of product, etc.), remains the same. Three variables must be provided 

with risk calculations: accident frequency, severity, and exposure. Traditionally, risk is defined 

as the expected frequency of unsafe events multiplied by the expected consequences. Exposure 

must be identified because increases in risk due to increased exposure can be easily distinguished 

from increases in risk due solely to implementation and use of the proposed product. 

Railroads intending to implement products covered by Subpart H may change operational 

characteristics at the same time in order to take advantage of the benefits of the new technology. 

Increased train volumes, passenger volumes, or operating speeds, or all three, may be likely 

changes to accompany implementation of Subpart H products. The rule requires the railroad to 

analyze the total change in risk, then separately identify and distinguish risk changes associated 

with the use of the product from risk changes due to changes in operating practices (i.e., risk 

changes due to increased/decreased operating speed, etc.). This procedure is necessary to make 

an accurate comparison of the relevant risks for purposes of determining compliance with the 

minimum performance standard in § 236.909(a) 

Changes in railroad operations, especially increases in traffic speeds and/or densities from those 

defined in the PSP safety analysis, may render the results obtained from a risk analysis invalid. 

Inspectors should be aware of the method of operations, traffic speeds, densities, and 
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type/size/weight of the trains and their cargo. Deviations by the railroad from the assumptions 

for these in the PSP require the railroad to resubmit an adjusted safety analysis. Unreported 

changes, or changes without an approved revised PSP, are unacceptable. 

CLASSIFICATION OF DEFECTS 

236.909.A1 Failure to make analysis or documentation available. 

236.909.B1 Failure to determine or demonstrate that the minimum performance standard has 

been met. 

236.909.C1 Failure of risk assessment to address safety risks of product. 

236.909.D1 Abbreviated risk assessment used when not appropriate. 

236.909.E1 Full risk assessment techniques not appropriate. 

§ 236.911 Exclusions. 

 (a) Does this subpart apply to existing systems? The requirements of this subpart do not 

apply to products in service as of June 6, 2005. Railroads may continue to implement and use 

these products and components from these existing products. 

 (b) How will transition cases be handled? Products designed in accordance with subparts A 

through G of this part which are not in service but are developed or are in the developmental 

stage prior to March 7, 2005, may be excluded upon notification to FRA by June 6, 2005, if 

placed in service by March 7, 2008. Railroads may continue to implement and use these 

products and components from these existing products. A railroad may at any time elect to have 

products that are excluded made subject to this subpart by submitting a PSP as prescribed in § 

236.913 and otherwise complying with this subpart. 

 (c) How are office systems handled? The requirements of this subpart do not apply to 

existing office systems and future deployments of existing office system technology. However, 

a subsystem or component of an office system must comply with the requirements of this subpart 

if it performs safety-critical functions within, or affects the safety performance of, a new or nextgeneration train control system. For purposes of this section, “office system” means a 

centralized computer-aided train-dispatching system or centralized traffic control board. 

 (d) How are modifications to excluded products handled? Changes or modifications to 

products otherwise excluded from the requirements of this subpart by this section are not 

excluded from the requirements of this subpart if they result in a degradation of safety or a 

material increase in safety-critical functionality. 

 (e) What other rules apply to excluded products? Products excluded by this section from the 

requirements of this subpart remain subject to subparts A through G of this part as applicable. 

Application: 

Paragraph (a) provides that the Subpart H does not apply to products in service on the effective 

date of this rule. Railroads employ numerous processor-based safety-critical products in their 

existing signal and train control systems. These existing systems have proven to provide a very 

high level of safety, reliability, and functionality. The safety record of this equipment is good 

and does not warrant the burden necessary to essentially re-prove that it is safe. Transit systems, 

except those that are connected to the general railroad system, are not directly regulated by FRA 
236-185 

at the national level. Field inspectors should be aware of products on their territory that fall 

under this category, and enforce compliance with the applicable portions of Subparts A through 

G. Inspectors should be aware that railroads have the option to have products which are 

excluded made subject to Subpart H by submitting a PSP for the product. Until such a PSP is 

approved, inspectors should continue to enforce compliance with Subparts A through G. 

Paragraph (b) addresses the products that are designed in accordance with Part 236, Subparts A 

through G, that were not in service on the effective date of this rule but which were in the 

developmental stage. These products are all now required to be in service. Field inspectors 

should be aware of the products in service in their territory, and be alert to the introduction of 

new safety-critical products. Introduction of new or novel products that do not have an approved 

PSP are in violation of this regulation. These products should be identified to headquarters staff, 

and their use discontinued until an approved PSP, or waiver to continue operations, is received 

and approved. 

 

Paragraph (c) addresses the exclusion of existing and future deployments of existing office 

systems technology. Currently, some railroads employ these dispatch systems as part of their 

existing signal and train control systems. These existing systems have been implemented 

voluntarily to enhance productivity and have proven to provide a reasonably high level of safety, 

reliability, and functionality. However, a subsystem or component of an office system must 

comply with Subpart H if it performs safety-critical functions within a new or next-generation 

signal or train control system. When an inspector notes an apparent safety-critical change to an 

office system where the railroad does not have a waiver or an approved PSP, the use of at least 

that portion of the system should be discontinued, and the inspector should inform headquarters 

staff of the situation. 

Paragraph (d) establishes requirements for modifications of excluded products. At some point, 

cumulative changes to excluded products will be significant enough to require the safety 

assurance processes of Subpart H to be followed. This point exists when a change results in 

degradation of safety or in a material increase in safety-critical functionality. Modifications 

caused by implementation details do not necessarily cause the product to become subject to 

Subpart H. These types of implementation modifications are minor in nature and are the result 

of site-specific physical constraints. Implementation modifications that will result in a 

degradation of safety or a material increase in safety-critical functionality, like a change in 

executive software, will cause the product to be subject to Subpart H and its requirements. 

Inspectors should be aware of system modifications to excluded systems, and advise 

headquarters staff to determine if the modification requires compliance with Subpart H. If 

advised by headquarters staff that Subpart H compliance is required, system operation should be 

discontinued until receipt of an approved PSP. 

Paragraph (e) clarifies the application of Subparts A through G to products excluded by this 

section. Inspectors should be aware of what products are covered by Subpart H, and which 

products are still covered by Subparts A through G, enforcing as appropriate. 

CLASSIFICATION OF DEFECTS 

236.911.A1 Non-excluded product or product modification implemented in violation of 

Subpart H. 
236-186 

§ 236.913 Filing and approval of PSPs. 

 (a) Under what circumstances must a PSP be prepared? A PSP must be prepared for each 

product covered by this subpart. A joint PSP must be prepared when: 

 (1) The territory on which a product covered by this subpart is normally subject to joint 

operations, or is operated upon by more than one railroad; and 

 (2) The PSP involves a change in method of operation. 

 (b) Under what circumstances must a railroad submit a petition for approval for a PSP or 

PSP amendment, and when may a railroad submit an informational filing? Depending on the 

nature of the proposed product or change, the railroad shall submit either an informational filing 

or a petition for approval. Submission of a petition for approval is required for PSPs or PSP 

amendments concerning installation of new or next-generation train control systems. All other 

actions that result in the creation of a PSP or PSP amendment require an informational filing and 

are handled according to the procedures outlined in paragraph (c) of this section. Applications 

for discontinuance and material modification of signal and train control systems remain governed 

by parts 235 and 211 of this chapter; and petitions subject to this section may be consolidated 

with any relevant application for administrative handling. 

 (c) What are the procedures for informational filings? The following procedures apply to 

PSPs and PSP amendments which do not require submission of a petition for approval, but rather 

require an informational filing: 

 (1) Not less than 180 days prior to planned use of the product in revenue service as described 

in the PSP or PSP amendment, the railroad shall submit an informational filing to the Associate 

Administrator for Safety, FRA, 1120 Vermont Avenue, N.W., Mail Stop 25, Washington, D.C. 

20590. The informational filing must provide a summary description of the PSP or PSP 

amendment, including the intended use of the product, and specify the location where the 

documentation as described in § 236.917(a)(1) is maintained. 

 (2) Within 60 days of receipt of the informational filing, FRA: 

 (i) Acknowledges receipt of the filing; 

 (ii) Acknowledges receipt of the informational filing and requests further information; or, 

 (iii) Acknowledges receipt of the filing and notifies the railroad, for good cause, that the 

filing will be considered as a petition for approval as set forth in paragraph (d) of this section, 

and requests such further information as may be required to initiate action on the petition for 

approval. Examples of good cause, any one of which is sufficient, include: the PSP describes a 

product with unique architectural concepts; the PSP describes a product that uses design or safety 

assurance concepts considered outside existing accepted practices (see Appendix C); and the PSP 

describes a locomotive-borne product that commingles safety-critical train control processing 

functions with locomotive operational functions. In addition, good 

cause includes any instance where the PSP or PSP amendment does not appear to support its 

safety claim of satisfaction of the performance standard, after FRA has requested further 

information as provided in paragraph (c)(2)(ii) of this section. 

 (d) What procedures apply to petitions for approval? The following procedures apply to 

PSPs and PSP amendments which require submission of a petition for approval: 

 (1) Petitions for approval involving prior FRA consultation. (i) The railroad may file a 

Notice of Product Development with the Associate Administrator for Safety not less than 30 

days prior to the end of the system design review phase of product development and 180 days 

prior to planned implementation, inviting FRA to participate in the design review process and 

receive periodic briefings and updates as needed to follow the course of product development. 

At a minimum, the Notice of Product Development must contain a summary description of the 

product to be developed and a brief description of goals for improved safety. 
236-187 

 (ii) Within 15 days of receipt of the Notice of Product Development, the Associate 

Administrator for Safety either acknowledges receipt or acknowledges receipt and requests more 

information. 

 (iii) If FRA concludes that the Notice of Product Development contains sufficient 

information, the Associate Administrator for Safety determines the extent and nature of the 

assessment and review necessary for final product approval. FRA may convene a technical 

consultation as necessary to discuss issues related to the design and planned development of the 

product. 

 (iv) Within 60 days of receiving the Notice of Product Development, the Associate 

Administrator for Safety provides a letter of preliminary review with detailed findings, including 

whether the design concepts of the proposed product comply with the requirements of this 

subpart, whether design modifications are necessary to meet the requirements of this subpart, and 

the extent and nature of the safety analysis necessary to comply with this subpart. 

 (v) Not less than 60 days prior to use of the product in revenue service, the railroad shall file 

with the Associate Administrator for Safety a petition for final approval. 

 (vi) Within 30 days of receipt of the petition for final approval, the Associate Administrator 

for Safety either acknowledges receipt or acknowledges receipt and requests more information. 

Whenever possible, FRA acts on the petition for final approval within 60 days of its filing by 

either granting it or denying it. If FRA neither grants nor denies the petition for approval within 

60 days, FRA advises the petitioner of the projected time for decision and conducts any further 

consultations or inquiries necessary to decide the matter. 

 (2) Other petitions for approval. The following procedures apply to petitions for approval of 

PSPs which do not involve prior FRA consultation as described in paragraph (d)(1) of this 

section. 

 (i) Not less than 180 days prior to use of a product in revenue service, the railroad shall file 

with the Associate Administrator for Safety a petition for approval. 

 (ii) Within 60 days of receipt of the petition for approval, FRA either acknowledges receipt, 

or acknowledges receipt and requests more information. 

 (iii) Whenever possible, considering the scope, complexity, and novelty of the product or 

change, FRA acts on the petition for approval within 180 days of its filing by either granting it or 

denying it. If FRA neither grants nor denies the petition for approval within 180 days, it remains 

pending, and FRA provides the petitioner with a statement of reasons why the petition has not 

yet been approved. 

 (e) What role do product users play in the process of safety review? (1) FRA will publish in 

the FEDERAL REGISTER periodically a topic list including docket numbers for informational 

filings and a petition summary including docket numbers for petitions for approval. 

 (2) Interested parties may submit to FRA information and views pertinent to FRA’s 

consideration of an informational filing or petition for approval. FRA considers comments to the 

extent practicable within the periods set forth in this section. In a proceeding consolidated with a 

proceeding under part 235 of this chapter, FRA considers all comments received. 

 (f) Is it necessary to complete field testing prior to filing the petition for approval? A 

railroad may file a petition for approval prior to completion of field testing of the product. The 

petition for approval should additionally include information sufficient for FRA to arrange 

monitoring of the tests. The Associate Administrator for Safety may approve a petition for 

approval contingent upon successful completion of the test program contained in the PSP or hold 

the petition for approval pending completion of the tests. 

 (g) How are PSPs approved? (1) The Associate Administrator for Safety grants approval of 

a PSP when: 

 (i) The petition for approval has been properly filed and contains the information required in 

§ 236.907; 
236-188 

 (ii) FRA has determined that the PSP complies with the railroad’s approved RSPP and 

applicable requirements of this subpart; and 

 (iii) The risk assessment supporting the PSP demonstrates that the proposed product satisfies 

the minimum performance standard stated in § 236.909. 

 (2) The Associate Administrator for Safety considers the following applicable factors when 

evaluating the risk assessment: 

 (i) The extent to which recognized standards have been utilized in product design and in the 

relevant safety analysis; 

 (ii) The availability of quantitative data, including calculations of statistical confidence levels 

using accepted methods, associated with risk estimates; 

 (iii) The complexity of the product and the extent to which it will incorporate or deviate from 

design practices associated with previously established histories of safe operation; 

 (iv) The degree of rigor and precision associated with the safety analyses, including the 

comprehensiveness of the qualitative analyses, and the extent to which any quantitative results 

realistically reflect appropriate sensitivity cases; 

 (v) The extent to which validation of the product has included experiments and tests to 

identify uncovered faults in the operation of the product; 

 (vi) The extent to which identified faults are effectively addressed; 

 (vii) Whether the risk assessment for the previous condition was conducted using the same 

methodology as that for operation under the proposed condition; and 

 (viii) If an independent third-party assessment is required or is performed at the election of 

the supplier or railroad, the extent to which the results of the assessment are favorable. 

 (3) The Associate Administrator for Safety also considers when assessing PSPs the safety 

requirements for the product within the context of the proposed method of operations, including: 

 (i) The degree to which the product is relied upon as the primary safety system for train 

operations; and 

 (ii) The degree to which the product is overlaid upon and its operation is demonstrated to be 

independent of safety-relevant rules, practices and systems that will remain in place following 

the change under review. 

 (4) As necessary to ensure compliance with this subpart and with the RSPP, FRA may attach 

special conditions to the approval of the petition. 

 (5) Following the approval of a petition, FRA may reopen consideration of the petition for 

cause. Cause for reopening a petition includes such circumstances as a credible allegation of 

error or fraud, assumptions determined to be invalid as a result of in-service experience, or one 

or more unsafe events calling into question the safety analysis underlying the approval. 

 (h) Under what circumstances may a third-party assessment be required, and by whom may 

it be conducted? (1) The PSP must be supported by an independent third party assessment of the 

product when FRA concludes it is necessary based upon consideration of the following factors: 

 (i) Those factors listed in paragraphs (g)(2)(i) through (g)(2)(vii) of this section; 

 (ii) The sufficiency of the assessment or audit previously conducted at the election of a 

supplier or railroad; and 

 (iii) Whether applicable requirements of subparts A through G of this part are satisfied. 

 (2) As used in this section, “independent third party” means a technically competent entity 

responsible to and compensated by the railroad (or an association on behalf of one or more 

railroads) that is independent of the supplier of the product. An entity that is owned or controlled 

by the supplier, that is under common ownership or control with the supplier, or that is otherwise 

involved in the development of the product is not considered “independent” within the meaning 

of this section. FRA may maintain a roster of recognized technically competent entities as a 

service to railroads selecting reviewers under this section; however, a railroad is not limited to 

entities currently listed on any such roster. 
236-189 

 (3) The third-party assessment must, at a minimum, consist of the activities and result in 

production of documentation meeting the requirements of Appendix D to this part. However, 

when requiring an assessment pursuant to this section, FRA specifies any requirements in 

Appendix D to this part which the agency has determined are not relevant to its concerns and, 

therefore, need not be included in the assessment. The railroad shall make the final assessment 

report available to FRA upon request. 

 (i) How may a PSP be amended? A railroad may submit an amendment to a PSP at any time 

in the same manner as the initial PSP. Notwithstanding the otherwise applicable requirements 

found in this section and § 236.915, changes affecting the safety-critical functionality of a 

product may be made prior to the submission and approval of the PSP amendment as necessary 

in order to mitigate risk. 

 (j) How may field testing be conducted prior to PSP approval? (1) Field testing of a product 

may be conducted prior to the approval of a PSP by the submission of an informational filing by 

a railroad. The FRA will arrange to monitor the tests based on the information provided in the 

filing, which must include: 

 (i) A complete description of the product; 

 (ii) An operational concepts document; 

 (iii) A complete description of the specific test procedures, including the measures that will 

be taken to protect trains and on-track equipment; 

 (iv) An analysis of the applicability of the requirements of subparts A through G of this part 

to the product that will not apply during testing; 

 (v) The date testing will begin; 

 (vi) The location of the testing; and 

 (vii) A description of any effect the testing will have on the current method of operation. 

 (2) FRA may impose such additional conditions on this testing as may be necessary for the 

safety of train operations. Exemptions from regulations other than those contained in this part 

must be requested through waiver procedures in part 211 of this chapter. 

Application: 

With the exception of subsections (a), (f), and (j), the majority of this section is not applicable to 

field inspectors. The regulations in this section describe the railroad’s requirements for notifying 

FRA of its preparation of a PSP to ensure compliance with procedures established in their RSPP, 

and the requirements of this subpart. 

Paragraph (a) establishes a requirement for preparation of a PSP for each product covered by this 

subpart, and discusses the circumstances under which a joint PSP must be prepared. A joint PSP 

must be prepared when (1) the territory on which a product covered by the subpart is normally 

subject to joint operations, or is operated upon by more than one railroad; and (2) the PSP 

involves a change in the method of operations. Inspectors must be aware of the conditions that 

apply to the PSP. Unless specifically approved in the PSP, joint operations, or changes in the 

method of operation are not permitted. These are considered violations. Inspectors discovering 

these should disallow operations and advise headquarters staff. 

Paragraph (f) allows railroads to file petitions for approval prior to field-testing and validation of 

the product. (See also paragraph (j) below.) If FRA approves the petition, the railroad may 

conduct testing operations using the system in question. These operations are considered 

temporary (pending submission and approval of the railroad’s PSP). Inspectors should verify 

that the railroad is not operating revenue trains under such an approval condition. If this is the 

case, then a violation has occurred. 
236-190 

FRA approval is necessary where the railroad seeks to test any product for which it would 

otherwise be required to seek a waiver for exemption of specific Part 236 regulations. For 

instance, when field-testing of the product will involve direct interface with train crewmembers, 

there may be a requirement for some control mechanisms to be in place. In addition, railroads 

will likely need to test products for operational concepts and safety-critical consideration of the 

product prior to implementation. 

Paragraph (j) identifies procedures for obtaining FRA approval to field test a Subpart H product. 

The information required for this filing, as described in paragraphs (j)(1)(i)–(j)(1)(vii), are 

necessary in order for FRA to make informed decisions regarding the safety of testing 

operations. This provides a simplified mechanism for exemptions of necessary portions of Part 

236. Exemptions from regulations other than those contained in Part 236 must be sought under 

waiver procedures contained in Part 211, FRA’s Rules of Practice. 

This rule states that FRA may impose conditions on field tests to assure safety of train 

operations. Such testing may implicate other safety issues, including adequacy of warning at 

highway-rail grade crossings (including Part 234 compliance), qualification of passenger 

equipment (Part 238), sufficiency of the track structure to support higher speeds or unbalance, 

and a variety of other safety issues, not all of which can be anticipated in any special approval 

procedure. “Clearing the railroad” for the test train answers only a portion of these issues. 

Inspectors may be asked to participate in this pre-implementation testing. If not, they should be 

aware of this testing and any temporary relief from the regulations granted to the railroad. If 

particular regulatory relief has not been granted, then the inspector should take action (as 

appropriate) in the instance of noncompliance being found. Similarly, if the railroad is found to 

be conducting test operations, and cannot demonstrate receipt of FRA approval, testing should be 

halted until FRA approval is obtained. 

CLASSIFICATION OF DEFECTS 

236.913.A1 Failure to prepare a PSP or PSP amendment as required. 

236.913.B1 Failure to submit a PSP or PSP amendment as required. 

236.913.C1 Failure to submit an informational filing as required. 

236.913.J1 Field testing without authorization or approval as required. 

§ 236.915 Implementation and operation. 

 (a) When may a product be placed or retained in service? (1) Except as stated in paragraphs 

(a)(2) and (a)(3) of this section, a railroad may operate in revenue service any product 180 days 

after filing with FRA the informational filing for that product. The FRA filing date can be found 

in FRA’s acknowledgment letter referred to in § 236.913(c)(2). 

 (2) Except as stated in paragraph (a)(3) of this section, if FRA approval is required for a 

product, the railroad shall not operate the product in revenue service until after the Associate 

Administrator for Safety has approved the petition for approval for that product pursuant to § 

236.913. 
236-191 

 (3) If after product implementation FRA elects, for cause, to treat the informational filing for 

the product as a petition for approval, the product may remain in use if otherwise consistent with 

the applicable law and regulations. FRA may impose special conditions for use of the product 

during the period of review for cause. 

 (b) How does the PSP relate to operation of the product? Each railroad shall comply with all 

provisions in the PSP for each product it uses and shall operate within the scope of initial 

operational assumptions and predefined changes identified by the PSP. Railroads may at any 

time submit an amended PSP according to the procedures outlined in 

§ 236.913. 

 (c) What precautions must be taken prior to interference with the normal functioning of a 

product? The normal functioning of any safety-critical product must not be interfered with in 

testing or otherwise without first taking measures to provide for safe movement of trains, 

locomotives, roadway workers and on-track equipment that depend on normal functioning of 

such product. 

 (d) What actions must be taken immediately upon failure of a safety-critical component? 

When any safety-critical product component fails to perform its intended function, the cause 

must be determined and 

the faulty component adjusted, repaired, or replaced without undue delay. Until repair of such 

essential components are completed, a railroad shall take appropriate action as specified in the 

PSP. See also §§ 236.907(d) and 236.917(b). 

Application: 

Paragraph (a) establishes requirements relating to when products may be implemented and used 

in revenue service. Paragraph (a)(1) discusses the standard for products which do not require 

FRA approval, but rather an informational filing. Paragraph (a)(2) addresses the standard for 

products which require that a petition for approval be submitted to FRA for approval. Such 

products shall not be used in revenue service prior to FRA approval. 

Paragraph (a)(3) excepts from the requirements of paragraphs (a)(1) and (a)(2) those products for 

which an informational filing had been filed initially, then FRA elected after implementation to 

treat the filing as a petition for approval. In the case where FRA chooses to treat an 

informational filing as a petition for approval after implementation, “for cause” is not intended to 

be restricted to the same interpretation given in § 236.913(c) for “good cause.” FRA envisions 

that cause for review after implementation will more likely be related to actual in-service 

performance than initial design safety considerations. 

Paragraph (b) establishes a requirement that railroads will not exceed maximum volumes, 

speeds, or any other parameter limit provided for in the PSP. On the other hand, a PSP could be 

based upon speed/volume parameters that are broader than the intended initial application, so 

long as the full range of sensitivity analyses are included in the supporting risk assessment. FRA 

feels this requirement will help ensure that comprehensive product risk assessments are 

performed before products are implemented. This paragraph also makes allowance for 

amendment of PSPs even after implementation. Railroads indicated they will need the ability to 

amend PSPs to correct initial assumptions after implementation. Furthermore, railroads feel that 

if operating conditions for which a product was designed are no longer applicable and safety 

levels have not been reduced, the necessary corresponding PSP amendments should be allowed. 

FRA agrees that a mechanism must be available to handle this kind of circumstance, but of 

course the degree of scrutiny afforded the amendment would depend upon the specific risk 

profile of the proposed change. 
236-192 

Paragraph (c) requires that each railroad ensure the integrity of a processor-based system not be 

compromised, by prohibiting the normal functioning of such system to be interfered with by 

testing or otherwise without first taking measures to provide for the safety of train movements, 

roadway workers, and on-track equipment that depend on the normal functioning of the system. 

This provision parallels current § 236.4, which applies to all devices. By requiring this 

paragraph, FRA merely intends to clarify that the standard in current § 236.4 applies to Subpart 

H products. 

Paragraph (d) requires, in the event of the failure of a component essential to the safety of a 

processor-based system to perform as intended, that the cause be identified and corrective action 

taken without undue delay. The paragraph also requires that, until repair is completed, the 

railroad be required to take appropriate measures to assure the safety of train movements, 

roadway workers, and on-track equipment. This requirement mirrors current requirement § 

236.11, which applies to all signal system components. 

CLASSIFICATION OF DEFECTS 

236.915.A1 Operation of a product without authorization or approval as required. 

236.915.B1 Failure to comply with the PSP as required. 

236.915.C1 Interference with the normal functioning of a safety-critical product without first 

taking necessary safety measures as required. 

236.915.D1 Failure to determine the cause of any safety-critical product component failure, 

and to adjust, repair, or replace the faulty component without undue delay. 

236.915D2 Until repair of faulty component is completed, failure to appropriate action as 

specified in the PSP. 

§ 236.917 Retention of records. 

 (a) What life-cycle and maintenance records must be maintained? (1) The railroad shall 

maintain at a designated office on the railroad: 

 (i) For the life-cycle of the product, adequate documentation to demonstrate that the PSP 

meets the safety requirements of the railroad’s RSPP and applicable standards in this subpart, 

including the risk assessment; 

 (ii) An Operations and Maintenance Manual, pursuant to § 236.919; and 

 (iii) Training records pursuant to § 236.923(b). 

 (2) Results of inspections and tests specified in the PSP must be recorded as prescribed in § 

236.110. 

 (3) Contractors of the railroad shall maintain at a designated office training records pursuant 

to § 236.923(b). 

 (b) What actions must the railroad take in the event of occurrence of a safety-relevant 

hazard? After the product is placed in service, the railroad shall maintain a database of all 

safety-relevant hazards as set forth in the PSP and those that had not been previously identified 

in the PSP. If the frequency of the safety-relevant hazards exceeds the threshold set forth in the 

PSP (see § 236.907(a)(6)), then the railroad shall: 
236-193 

(1) Report the inconsistency in writing (by mail, facsimile, e-mail, or hand delivery to the 

Director, Office of Safety Assurance and Compliance, FRA, 1120 Vermont Ave., N.W., Mail 

Stop 25, Washington, D.C. 20590, within 15 days of discovery. Documents that are hand 

delivered must not be enclosed in an envelope. 

 (2) Take prompt countermeasures to reduce the frequency of the safety-relevant hazard(s) 

below the threshold set forth in the PSP; and 

 (3) Provide a final report to the FRA Director, Office of Safety Assurance and Compliance, 

on the results of the analysis and countermeasures taken to reduce the frequency of the safetyrelevant hazard(s) below the threshold set forth in the PSP when the problem is resolved. 

Application: 

The railroad is required to maintain adequate documentation to demonstrate that the PSP meets 

the safety requirements of the RSPP and applicable standards in this subpart, including the risk 

assessment, and that the product conforms to the PSP. 

All the documents and records required by this section must be maintained at a designated office 

on the railroad. All documents and records must be available for FRA inspection and copying 

during normal business hours. The following records are required to be maintained: 

 The product Operations and Maintenance Manual, as described in § 236.919 for the 

product life-cycle (i.e., the point where the product has been permanently and completely 

removed from operational service anywhere on the railroad). 

 Railroad training records which designate persons who are qualified under 

§ 236.923(b) until new designations are recorded or for at least one year after such 

persons leave applicable service. 

 Implementation, maintenance, inspection, and testing records (as described in 

§ 236.907(a)(18)(ii)) be recorded as prescribed in § 236.110. 

 Contractors training records at a designated office which designate persons who are 

qualified under § 236.923. Contractors training records are subject to the same 

provisions as those for railroads. 

Inspectors should have access to these documents. If the railroad asserts that they are not 

available locally to the inspector, the inspector should contact the supervisory specialist in the 

region where the documents are held, or headquarters staff. The same criteria used for document 

inspection associated with Subparts A through G are applicable. 

After the product is placed in service, railroads must maintain a database of safety-relevant 

hazards as described in § 236.907(a)(6), which occur or are discovered on the product. This 

database information shall also be available for inspection and replication by FRA and FRA 

certified State inspectors, during normal business hours. 

Inspectors should also have access to these documents. If the railroad asserts that they are not 

available locally to the inspector, the inspector should contact the supervisory specialist in the 

region where the documents are held, or headquarters staff. The same criteria used for document 

inspection associated with Subparts A through G are applicable. 

 
236-194 

If an inspector discovers the frequency of occurrence for a safety-relevant hazard exceeds the 

threshold value provided in its PSP, prompt countermeasures are required to have been made by 

the railroad to reduce the frequency of the safety-relevant hazards or eliminate the hazard. There 

may be situations where reducing the severity of such hazards will suffice for an equivalent 

reduction in risk. For example, reducing operating speed may not reduce the frequency of 

certain hazards involving safety-critical products, but it would in most cases reduce the severity 

of such hazards. 

Upon discovery of a hazard exceeding the PSP threshold, inspectors should verify that the 

railroad has reported the hazard occurrence to FRA within 15 days. FRA currently allows faxing 

or emailing of reports required by §§ 233.7 and 234.9, involving signal failure and grade 

crossing signal system failure, respectively. This is extended to include products covered by 

Subpart H. The failure reports may be in writing by mail, facsimile, email, messenger, or hand 

delivery. Documents that are hand delivered to FRA must not be enclosed in an envelope, as all 

envelopes are required to be routed through the DOT mailroom. 

Inspectors should also verify that the railroad has provided a final report on how a safetyrelevant hazard was corrected or mitigated. 

The scope and difficulty of undertaking these actions could vary dramatically. In some cases, an 

adequate response could be completed within days. In other cases the total response could take 

years, even with prompt, deliberate action. If the actions were to take a significant time, FRA 

would expect the railroad to make progress reports to FRA. The reporting requirement of § 

236.917(b) is not intended to excuse lack of compliance with current reporting requirements of 

Part 233. In the case of a false proceed signal failure, FRA would not expect the railroad to wait 

for the frequency of such occurrences to exceed the threshold reporting level assigned in the 

hazard log. Rather, current § 233.7 requires all such instances to be reported. 

CLASSIFICATION OF DEFECTS 

236.917.A1 Failure to maintain records as required. 

236.917.B1 Failure to maintain a database of all safety-relevant hazards as required. 

236.917.B2 Failure to report to the FRA the frequency of safety-relevant hazards exceeding 

the threshold set forth in the PSP. 

236.917.B3 Failure to take prompt countermeasures to reduce the frequency of safety-relevant 

hazards below the threshold set forth in the PSP. 

236.917.B4 Failure to provide final report to the FRA on the results of the analysis and 

countermeasures taken when the problem is resolved. 

§ 236.919 Operations and Maintenance Manual. 

 (a) The railroad shall catalog and maintain all documents as specified in the PSP for the 

installation, maintenance, repair, modification, inspection, and testing of the product and have 

them in one Operations and Maintenance Manual, readily available to persons required to 

perform such tasks and for inspection by FRA and FRA-certified State inspectors. 
236-195 

 (b) Plans required for proper maintenance, repair, inspection, and testing of safety-critical 

products must be adequate in detail and must be made available for inspection by FRA and FRAcertified State inspectors where such products are deployed or maintained. They must identify 

all software versions, revisions, and revision dates. Plans must be legible and correct 

 (c) Hardware, software, and firmware revisions must be documented in the Operations and 

Maintenance Manual according to the railroad’s configuration management control plan and any 

additional configuration/revision control measures specified in the PSP. 

 (d) Safety-critical components, including spare equipment, must be positively identified, 

handled, replaced, and repaired in accordance with the procedures specified in the PSP 

Application: 

This section works with §§ 236.815, 236.905, and 236.907 that require all specified 

documentation contained in the PSP necessary for the installation, repair, modification, and 

testing of a product be placed in an Operations and Maintenance Manual for that product and be 

made available to both persons required to perform such tasks and to FRA. 

The Operations and Maintenance Manual includes the requirement that plans necessary for 

proper maintenance and testing of products be correct, legible, and available where such systems 

are deployed or maintained, and that they identify the hardware, software, and firmware 

revisions in accordance with the configuration management requirements specified in the PSP. 

This manual should be available to the inspector at all times. 

 

The railroad should be able to demonstrate to the inspector that safety-critical components 

contained in processor-based systems, including spare equipment, be identified, replaced, 

handled, and repaired in accordance with the configuration management requirements specified 

in the PSP. 

An electronic format is an appropriate medium for such a manual. Electronic copies of the 

manual should be maintained in the same manner as other electronic records, and the manual is 

required to be included in the railroad’s configuration management plan (with the master copy 

and dated amendments carefully maintained so that the status of instructions to the field, as of 

any given date, can be readily determined). 

 

CLASSIFICATION OF DEFECTS 

236.919.A1 Failure to catalog and maintain all documents specified in the PSP in one 

operations and maintenance manual. 

236.919.A2 Operations and maintenance manual not readily available to those performing the 

tasks. 

236.919.A3 Operations and maintenance manual not readily available for inspection by FRA 

or FRA-certified State inspectors. 

§ 236.921 Training and qualification program, general. 

 (a) When is training necessary and who must be trained? Employers shall establish and 

implement training and qualification programs for products subject to this subpart. These 
236-196 

programs must meet the minimum requirements set forth in the PSP and in §§ 236.923 through 

236.929 as appropriate, for the following personnel: 

 (1) Persons whose duties include installing, maintaining, repairing, modifying, inspecting, 

and testing safety-critical elements of the railroad's products, including central office, wayside, 

or onboard subsystems; 

 (2) Persons who dispatch train operations (issue or communicate any mandatory directive 

that is executed or enforced, or is intended to be executed or enforced, by a train control system 

subject to this subpart); 

 (3) Persons who operate trains or serve as a train or engine crewmember subject to 

instruction and testing under part 217 of this chapter, on a train operating in territory where a 

train control system subject to this subpart is in use; 

 (4) Roadway workers whose duties require them to know and understand how a train control 

system affects their safety and how to avoid interfering with its proper functioning; and 

 (5) The direct supervisors of persons listed in paragraphs (a)(1) through (a)(4) of this section. 

 (b) What competencies are required? The employer’s program must provide training for 

persons who perform the functions described in paragraph (a) of this section to ensure that they 

have the necessary knowledge and skills to effectively complete their duties related to processorbased signal and train control equipment. 

Application: 

This section sets forth the general requirements of an employer’s training and qualification 

programs related to safety-critical processor-based signal and train control products. The term 

“employer” means a railroad, a contractor, or a supplier whose employees are performing the 

duties described in Paragraphs (a)(1) through (a)(5). Training programs must meet the minimum 

requirements listed in §§ 236.923 through 236.929, as appropriate, and any more stringent 

requirements identified within the PSP for the product. Persons cited in paragraph (a) must be 

trained to the appropriate degree to ensure that they have the necessary knowledge and skills to 

effectively complete their duties related to operation and maintenance of products. The program 

will provide training for persons whose duties include inspecting, testing, maintaining, or 

repairing elements of a railroad’s safety-critical processor-based signal and train control systems, 

including central office, wayside, or onboard subsystems. In addition, it will include training 

required for personnel dispatching and operating trains in territory where advanced train control 

is in use, and for roadway workers whose duties require knowledge and understanding of the 

operating rules within the system. Finally, it will include supervisors of the foregoing persons. 

Railroads are responsible for training their own employees. Contractors, including suppliers 

whose employees are performing the duties described in this section, are also responsible for 

training their own employees. In short, employers are responsible for having their employees 

who perform work covered by this section trained and qualified. 

If FRA finds untrained contractors performing work that requires training, both the contractor 

and railroad may potentially be subject to civil penalty enforcement activity. Railroads should 

provide proof that contractors have training programs that comply with this section and that the 

contractors are using trained and qualified personnel to perform work on a railroad’s processorbased safety-critical signal and train control products. If FRA finds untrained contractor 

employees conducting work which requires training, FRA can take enforcement action against 

both the contractor and the railroad. If the railroad has placed a clear contractual responsibility 

on the provider of services to train personnel and maintain appropriate records, FRA would 
236-197 

normally proceed first against the contractor. In any event, FRA will expect to see prompt 

corrective action. 

CLASSIFICATION OF DEFECTS 

236.921.A1 Failure to establish and implement training and qualification programs for 

products subject to subpart H, meeting minimum requirements for required 

personnel. 

236.921.B1 Failure to provide training to employees to ensure they have the necessary 

knowledge and skills to effectively complete their duties related to processorbased signal and train control equipment. 

§ 236.923 Task analysis and basic requirements. 

 (a) How must training be structured and delivered? As part of the program required by § 

236.921, the employer shall, at a minimum: 

 (1) Identify the specific goals of the training program with regard to the target population 

(craft, experience level, scope of work, etc.), task(s), and desired success rate; 

 (2) Based on a formal task analysis, identify the installation, maintenance, repair, 

modification, inspection, testing, and operating tasks that must be performed on a railroad's 

products. This includes the development of failure scenarios and the actions expected under 

such scenarios; 

 (3) Develop written procedures for the performance of the tasks identified; 

 (4) Identify the additional knowledge, skills, and abilities above those required for basic job 

performance necessary to perform each task; 

 (5) Develop a training curriculum that includes classroom, simulator, computer-based, handson, or other formally structured training designed to impart the knowledge, skills, and abilities 

identified as necessary to perform each task; 

 (6) Prior to assignment of related tasks, require all persons mentioned in § 236.921(a) to 

successfully complete a training curriculum and pass an examination that covers the product and 

appropriate rules and tasks for which they are responsible (however, such persons may perform 

such tasks under the direct onsite supervision of a qualified person prior to completing such 

training and passing the examination); 

 (7) Require periodic refresher training at intervals specified in the PSP that includes 

classroom, simulator, computer-based, hands-on, or other formally structured training and 

testing, except with respect to basic skills for which proficiency is known to remain high as a 

result of frequent repetition of the task; and 

 (8) Conduct regular and periodic evaluations of the effectiveness of the training program 

specified in § 236.923(a)(1) verifying the adequacy of the training material and its validity with 

respect to current railroads products and operations 

 (b) What training records are required? Employers shall retain records which designate 

persons who are qualified under this section until new designations are recorded or for at least 

one year after such persons leave applicable service. These records shall be kept in a designated 

location and be available for inspection and replication by FRA and FRA-certified State 

inspector. 
236-198 

Application: 

This section amplifies on the requirements of § 236.921 of what the inspector should expect to 

observe when examining a railroad’s training program. While an inspector may find a variety of 

curriculum which includes either classroom, hands-on, or other formally structured training 

designed to impart the knowledge and skills necessary to perform each task, the required task 

analysis will tailor each program to the needs of the particular system to which it applies. The 

training program will identify inspection, testing, maintenance, repairing, dispatching, and 

operating tasks for signal and train control equipment and develop written procedures for 

performance of those tasks. 

The target population is identified in § 236.921(a)(1) through (a)(5). Training programs must be 

specifically tailored to each category of employee required to be trained and must meet the 

minimum requirements listed in §§ 236.923 through 236.929, as appropriate, and any more 

stringent requirements in the PSP for the product. 

Managers and supervisors must be trained to carry out the functions their duties require. If a 

direct supervisor is in a position where he or she may have to fulfill the responsibilities or duties 

of a subordinate, he or she must have the requisite knowledge and training to do so. If, however, 

a manager or supervisor will likely never need to fulfill the duties of a subordinate, and that 

person is not expected to provide technical oversight for certain functions, he or she may not 

need to be trained on those functions. 

All persons subject to training requirements and their direct supervisors must successfully 

complete the training curriculum and pass an examination for the tasks for which they are 

responsible. For example, a person who operates a train would not require training on how to 

inspect, test, or maintain the equipment unless the person was also assigned to perform those 

tasks. Generally, appropriate training must be given to each of these employees prior to task 

assignment. However, an employee may be allowed to perform a task for which that person has 

not received the appropriate training only if the employee does so under the direct, onsite 

supervision of a qualified person. Direct supervisor is intended to mean the immediate, firstlevel supervisor to whom the employee reports. 

Periodic refresher training is to be conducted at intervals specified in the PSP. This periodic 

training must include either classroom, hands-on, computer-based training, or other formally 

structured training in order that railroad employees and contractor employees maintain the 

knowledge and skills. 

 

There is a requirement to compare actual and desired success rates for the examination. The 

objective of this requirement is twofold. The first is to determine if the training program 

materials and curriculum are imparting the specific knowledge, skills, and abilities to accomplish 

the stated goals of the training program. The second is to determine if the stated goals of the 

training program reflect the correct and current products and operations. 

 

Ongoing regular verification of the results of the training process is required to ensure that the 

training program materials and curriculum are relevant, the learning objectives are being met, 

and the necessary knowledge, skills, and abilities are actually being imparted. Without regular 

feedback, verification and validation (and if necessary, adjustments, to ensure the necessary 

relevancy and effectiveness) cannot occur. 
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Railroads will maintain railroad employee training records. Contractors, including suppliers, 

must maintain records on contractor employees who perform work covered by this section. FRA 

expects to have access to the training records of contractor and supplier employees whose work 

functions are covered by the training requirements of this section. If FRA cannot attain access to 

such records, the railroad, and the contractor or supplier, may be subject to civil penalty 

enforcement activity. 

These records must be kept until new designations are recorded or for at least 1 year after such 

persons leave applicable service, and must be available for FRA inspection and copying. 

CLASSIFICATION OF DEFECTS 

236.923.A1 Failure to develop an acceptable training program as required. 

236.923.A2 Failure to train persons as required. 

236.923.A3 Failure to conduct evaluation of training program as required. 

236.923.B1 Failure to maintain training program records as required. 

§ 236.925 Training specific to control office personnel. 

 Any person responsible for issuing or communicating mandatory directives in territory where 

products are or will be in use must be trained in the following areas, as applicable: 

 (a) Instructions concerning the interface between the computer-aided dispatching system and 

the train control system, with respect to the safe movement of trains and other on-track 

equipment; 

 (b) Railroad operating rules applicable to the train control system, including provision for 

movement and protection of roadway workers, unequipped trains, trains with failed or cut-out 

train control onboard systems, and other on-track equipment; and 

 (c) Instructions concerning control of trains and other on-track equipment in case the train 

control system fails, including periodic practical exercises or simulations, and operational testing 

under part 217 of this chapter to ensure the continued capability of the personnel to provide for 

safe operations under the alternative method of operation 

Application: 

This section identifies to the inspector additional specialized training that must be provided to 

employees responsible for issuing or communicating mandatory directives. The training must 

include instructions concerning the interface between computer-aided dispatching systems and 

processor-based train control systems as applicable to the safe movement of trains and other ontrack equipment. 

The training must also include operating rules that pertain to the train control system, including 

the provision for moving unequipped trains and trains on which the train control system has 

failed or been cut-out en route, rules and procedures for the protection of roadway workers and 

equipment, and instructions when a train control system fails. This rule also requires periodic 
236-200 

practical exercises or simulations and operational testing under Part 217 to assure that personnel 

are capable of providing for safe operations under alternative operating methods. 

CLASSIFICATION OF DEFECTS 

236.925.A1 Failure to provide training specific to control office personnel as required. 

§ 236.927 Training specific to locomotive engineers and other operating personnel. 

 

 (a) What elements apply to operating personnel? Training provided under this subpart for 

any locomotive engineer or other person who participates in the operation of a train in train 

control territory must be defined in the PSP and the following elements must be addressed: 

 (1) Familiarization with train control equipment onboard the locomotive and the functioning 

of that equipment as part of the system and in relation to other onboard systems under that 

person’s control; 

 (2) Any actions required of the onboard personnel to enable, or enter data to, the system, 

such as consist data, and the role of that function in the safe operation of the train; 

 (3) Sequencing of interventions by the system, including pre-enforcement notification, 

enforcement notification, penalty application initiation and post-penalty application procedures; 

 (4) Railroad operating rules applicable to the train control system, including provisions for 

movement and protection of any unequipped trains, or trains with failed or cut-out train control 

onboard systems and other on-track equipment; 

 (5) Means to detect deviations from proper functioning of onboard train control equipment 

and instructions regarding the actions to be taken with respect to control of the train and 

notification of designated railroad personnel; and 

 (6) Information needed to prevent unintentional interference with the proper functioning of 

onboard train control equipment. 

 (b) How must locomotive engineer training be conducted? Training required under this 

subpart for a locomotive engineer, together with required records, must be integrated into the 

program of training required by part 240 of this chapter. 

 (c) What requirements apply to full automatic operation? The following special 

requirements apply in the event a train control system is used to effect full automatic operation of 

the train: 

 (1) The PSP must identify all safety hazards to be mitigated by the locomotive engineer. 

 (2) The PSP must address and describe the training required with provisions for the 

maintenance of skills proficiency. As a minimum, the training program must: 

 (i) As described in § 236.923(a)(2), develop failure scenarios which incorporate the safety 

hazards identified in the PSP, including the return of train operations to a fully manual mode; 

 (ii) Provide training, consistent with § 236.923(a), for safe train operations under all failure 

scenarios and identified safety hazards that affect train operations; 

 (iii) Provide training, consistent with § 236.923(a), for safe train operations under manual 

control; and 

 (iv) Consistent with § 236.923(a), ensure maintenance of manual train operating skills by 

requiring manual starting and stopping of the train for an appropriate number of trips and by one 

or more of the following methods: 

 (A) Manual operation of a train for a 4-hour work period; 

 (B) Simulated manual operation of a train for a minimum of 4 hours in a Type I simulator as 

required; or 

 (C) Other means as determined following consultation between the railroad and designated 
236-201 

representatives of the affected employees and approved by the FRA. The PSP must designate 

the appropriate frequency when manual operation, starting, and stopping must be conducted, and 

the appropriate frequency of simulated manual operation. 

Application: 

This section identifies to the inspector additional specialized training that must be provided to 

locomotive engineers and other operating personnel who interact with processor-based train 

control systems. “Other operating personnel” means onboard train and engine crewmembers 

(i.e, conductors, brakemen, and assistant engineers). With respect to certified locomotive 

engineers, the training requirements of this section must be integrated into the training 

requirements of 49 CFR Part 240. 

The training must contain familiarization with the onboard processor-based equipment and the 

functioning of that equipment as part of a train control system and its relationship to other 

onboard systems under that person’s control. The program must, at a minimum, address all the 

topics identified in paragraphs (a)(1) through (a)(6). The training program must also cover all 

notifications by the system (i.e., onboard displays) and actions or responses to such notifications 

required by onboard personnel, safety hazards to be mitigated by the locomotive engineer, as 

well as how each action or response ensures proper operation of the system and safe operation of 

the train. 

Each railroad has the flexibility to develop its locomotive engineer training program to be 

applicable to the particular system being installed by that railroad. FRA recognizes that there is 

no one curriculum across the board that will generally satisfy the locomotive engineer training 

requirements. As with the general training requirements, the requisite task analysis will be 

specific to the functions of the system or systems of each railroad. The training requirements can 

be worked out individually among the railroad and its labor representatives, subject to approval 

of the FRA. In all cases, the PSP must define the appropriate training intervals for these tasks. 

CLASSIFICATION OF DEFECTS 

236.927.A1 Failure to provide training specific to locomotive engineers and other operating 

personnel as required. 

§ 236.929 Training specific to roadway workers. 

 

 (a) How is training for roadway workers to be coordinated with part 214? Training required 

under this subpart for a roadway worker must be integrated into the program of instruction 

required under part 214, subpart C of this chapter (“Roadway Worker Protection”), consistent 

with task analysis requirements of § 236.923. This training must provide instruction for roadway 

workers who provide protection for themselves or roadway work groups. 

 (b) What subject areas must roadway worker training include? (1) Instruction for roadway 

workers must ensure an understanding of the role of processor-based signal and train control 

equipment in establishing protection for roadway workers and their equipment. 

 (2) Instruction for roadway workers must ensure recognition of processor-based signal and 

train control equipment on the wayside and an understanding of how to avoid interference with 

its proper functioning. 

 (3) Instructions concerning the recognition of system failures and the provision of alternative 

methods of on-track safety in case the train control system fails, including periodic practical 
236-202 

exercises or simulations and operational testing under part 217 of this chapter to ensure the 

continued capability of roadway workers to be free from the danger of being struck by a moving 

train or other on-track equipment. 

Application: 

This section identifies to the inspector additional specialized training that must be provided to 

roadway workers and other maintenance-of-way personnel and as it associates with the program 

of instruction required under Part 214, Subpart C, Roadway Worker Protection. This training is 

designed to provide instruction for workers who obtain protection for roadway work groups or 

themselves. 

The training must include instruction to ensure (1) an understanding of the role of a processorbased train control system in establishing protection for workers and their equipment (whether at 

a work zone or while moving on-track between work locations), (2) recognition of processorbased signal and train control equipment on the wayside, and (3) an understanding of how to 

avoid interference with its proper functioning. This section also requires training on procedures 

during abnormal operations such as system failures, the operation of unequipped trains, or the 

operation of a train with failed or cut-out onboard equipment. Roadway workers, uniquely 

situated out on the right-of-way, are at risk of being struck by trains and on-track equipment. 

Given the potential for exposure to extreme peril, specific and periodic drills on that training is 

required. 

CLASSIFICATION OF DEFECTS 

236.929.A1 Failure to provide training specific to roadway workers as required. 

Subpart I – Positive Train Control Systems

§ 236.1001 Purpose and scope. 

 (a) This subpart prescribes minimum, performance-based safety standards for PTC systems 

required by 49 U.S.C. 20157, this subpart, or an FRA order, including requirements to ensure 

that the development, functionality, architecture, installation, implementation, inspection, testing, 

operation, maintenance, repair, and modification of those PTC systems will achieve and maintain 

an acceptable level of safety. This subpart also prescribes standards to ensure that personnel 

working with, and affected by, safety-critical PTC system related products receive appropriate 

training and testing. 

 (b) Each railroad may prescribe additional or more stringent rules, and other special 

instructions, that are not inconsistent with this subpart. 

 (c) This subpart does not exempt a railroad from compliance with any requirement of 

subparts A through H of this part or parts 233, 234, and 235 of this chapter, unless: 

 (1) It is otherwise explicitly excepted by this subpart; or 

 (2) The applicable PTCSP, as defined under § 236.1003 and approved by FRA under § 

236.1015, provides for such an exception per § 236.1013. 
236-203 

Application: 

This section describes both the purpose and the scope of Subpart I. Subpart I provides 

performance-based regulations for the development, test, installation, and maintenance of PTC 

systems, and the associated personnel training requirements, that are mandated for installation by 

FRA. This subpart details the process and identifies the documents that railroads and operators of 

passenger trains are to use and incorporate in their PTC implementation plans. This subpart also 

details the process and procedure for obtaining FRA approval of such plans. 

CLASSIFICATION OF DEFECTS 

§ 236.1001.B1 Railroad prescribed more stringent rules that are inconsistent with this subpart. 

§ 236.1001.B2 Railroad prescribed more stringent special instructions that are inconsistent with 

this subpart. 

§ 236.1003 Definitions. 

(a) Definitions contained in subparts G and H of this part apply equally to this subpart. 

(b) The following definitions apply to terms used only in this subpart unless otherwise stated: 

After-arrival mandatory directive means an authority to occupy a track which is issued to a 

train that is not effective and not to be acted upon until after the arrival and passing of a train, or 

trains, specifically identified in the authority. 

Associate Administrator means the FRA Associate Administrator for Railroad Safety/Chief 

Safety Officer. 

Class I railroad means a railroad which in the last year for which revenues were reported 

exceeded the threshold established under regulations of the Surface Transportation Board (49 

CFR part 1201.1-1 (2008)). 

Cleartext means the un-encrypted text in its original, human readable, form. It is the input of 

an encryption or encipher process, and the output of an decryption or decipher process. 

Controlling locomotive means Locomotive, controlling, as defined in § 232.5 of this chapter. 

Host railroad means a railroad that has effective operating control over a segment of track. 

Interoperability means the ability of a controlling locomotive to communicate with and 

respond to the PTC railroad's positive train control system, including uninterrupted movements 

over property boundaries. 

Limited operations means operations on main line track that have limited or no freight 

operations and are approved to be excluded from this subpart’s PTC system implementation and 

operation requirements in accordance with § 236.1019(c); 

Main line means, except as provided in § 236.1019 or where all trains are limited to restricted 

speed within a yard or terminal area or on auxiliary or industry tracks, a segment or route of 

railroad tracks: 

(1) Of a Class I railroad, as documented in current timetables filed by the Class I railroad 

with the FRA under § 217.7 of this title, over which 5,000,000 or more gross tons of railroad 

traffic is transported annually; or 

(2) Used for regularly scheduled intercity or commuter rail passenger service, as defined in 

49 U.S.C. 24102, or both. Tourist, scenic, historic, or excursion operations as defined in part 238 

of this chapter are not considered intercity or commuter passenger service for purposes of this 

part. 
236-204 

Main line track exclusion addendum (“MTEA”) means the document submitted under § 

236.1011 and § 236.1019 requesting to designate track as other than main line. 

Medium speed means, Speed, medium, as defined in subpart G of this part. 

NPI means a Notice of Product Intent (“NPI”) as further described in § 236.1013. 

PTC means positive train control as further described in § 236.1005. 

PTCDP means a PTC Development Plan as further described in § 236.1013. 

PTCIP means a PTC Implementation Plan as required under 49 U.S.C. 20157 and further 

described in § 236.1011. 

PTCPVL means a PTC Product Vendor List as further described in § 236.1023. 

PTCSP means a PTC Safety Plan as further described in § 236.1015. 

PTC railroad means each Class I railroad and each entity providing regularly scheduled 

intercity or commuter rail passenger transportation required to implement or operate a PTC 

system. 

PTC System Certification means certification as required under 49 U.S.C. 20157 and further 

described in §§ 236.1009 and 236.1015. 

Request for Amendment (“RFA”) means a request for an amendment of a plan or system 

made by a PTC railroad in accordance with § 236.1021. 

Request for Expedited Certification (“REC”) means, as further described in § 236.1031, a 

request by a railroad to receive expedited consideration for PTC System Certification. 

Restricted speed means, Speed, restricted, as defined in subpart G of this part. 

Safe State means a system state that, when the system fails, cannot cause death, injury, 

occupational illness, or damage to or loss of equipment or property, or damage to the 

environment. 

Segment of track means any part of the railroad where a train operates. 

Temporal separation means that passenger and freight operations do not operate on any 

segment of shared track during the same period and as further defined under § 236.1019 process 

or processes in place to assure that result. 

Tenant railroad means a railroad, other than a host railroad, operating on track upon which a 

PTC system is required. 

Track segment means segment of track. 

Type Approval means a number assigned to a particular PTC system indicating FRA 

agreement that the PTC system could fulfill the requirements of this subpart. 

Train means one or more locomotives, coupled with or without cars. 

Application:

Where possible and practicable, FRA prefers to provide explicit definitions for terms and 

concepts rather than rely solely on a shared understanding of a term through use. 

§ 236.1005 Requirements for Positive Train Control systems. 

(a) PTC system requirements. Each PTC system required to be installed under this subpart 

shall: 

(1) Reliably and functionally prevent: 

(i) Train-to-train collisions—including collisions between trains operating over rail-to-rail atgrade crossings in accordance with the following risk-based table or alternative arrangements 

providing an equivalent level of safety as specified in an FRA approved PTCSP: 
236-205 

Crossing Type Max Speed Protection Required 

(A) Interlocking – one or 

more PTC routes intersecting 

with one or more non-PTC 

routes 

(B) Interlocking – one or 

more PTC routes intersecting 

with one or more non-PTC 

routes 

(C) Interlocking – all PTC 

routes intersecting 

< 40 miles per hour...... 

> 40 miles per hour...... 

Any speed................. 

Interlocking signal arrangement in 

accordance with the requirements of 

subparts A-G of this part and PTC 

enforced stop on PTC routes. 

Interlocking signal arrangement in 

accordance with the requirements of 

subparts A-G of this part, PTC enforced 

stop on all PTC routes, and either the 

use of other than full PTC technology 

that provides positive stop enforcement 

or a split-point derail incorporated into 

the signal system accompanied by 20 

miles per hour maximum allowable 

speed on the approach of any 

intersecting non-PTC route. 

Interlocking signal arrangements in 

accordance with the requirements of 

subparts A-G of this part, and PTC 

enforced stop on all routes. 

(ii) Overspeed derailments, including derailments related to railroad civil engineering speed 

restrictions, slow orders, and excessive speeds over switches and through turnouts; 

(iii) Incursions into established work zone limits without first receiving appropriate authority 

and verification from the dispatcher or roadway worker in charge, as applicable and in 

accordance with part 214 of this chapter; and 

(iv) The movement of a train through a main line switch in the improper position as further 

described in paragraph (e) of this section. 

 (2) Include safety-critical integration of all authorities and indications of a wayside or cab 

signal system, or other similar appliance, method, device, or system of equivalent safety, in a 

manner by which the PTC system shall provide associated warning and enforcement to the 

extent, and except as, described and justified in the FRA approved PTCDP or PTCSP, as 

applicable; 

(3) As applicable, perform the additional functions specified in this subpart; 

(4) Provide an appropriate warning or enforcement when: 

(i) A derail or switch protecting access to the main line required by § 236.1007, or otherwise 

provided for in the applicable PTCSP, is not in its derailing or protecting position, respectively; 

(ii) A mandatory directive is issued associated with a highway-rail grade crossing warning 

system malfunction as required by §§ 234.105, 234.106, or 234.107; 

(iii) An after-arrival mandatory directive has been issued and the train or trains to be waited 

on has not yet passed the location of the receiving train; 

(iv) Any movable bridge within the route ahead is not in a position to allow permissive 

indication for a train movement pursuant to § 236.312; and 
236-206 

(v) A hazard detector integrated into the PTC system that is required by paragraph (c) of this 

section, or otherwise provided for in the applicable PTCSP, detects an unsafe condition or 

transmits an alarm; and 

(5) Limit the speed of passenger and freight trains to 59 miles per hour and 49 miles per 

hour, respectively, in areas without broken rail detection or equivalent safeguards. 

(b) PTC system installation. (1) Lines required to be equipped. Except as otherwise 

provided in this subpart, each Class I railroad and each railroad providing or hosting intercity or 

commuter passenger service shall progressively equip its lines as provided in its approved PTCIP 

such that, on and after December 31, 2015, a PTC system certified under § 236.1015 is installed 

and operated by the host railroad on each: 

(i) Main line over which is transported any quantity of material poisonous by inhalation 

(PIH), including anhydrous ammonia, as defined in §§ 171.8, 173.115 and 173.132 of this title; 

(ii) Main line used for regularly provided intercity or commuter passenger service, except as 

provided in § 236.1019; and 

(iii) Additional line of railroad as required by the applicable FRA approved PTCIP, this 

subpart, or an FRA order requiring installation of a PTC system by that date. 

(2) Initial baseline identification of lines. For the purposes of paragraph (b)(1)(i) of this 

section, the baseline information necessary to determine whether a Class I railroad’s track 

segment shall be equipped with a PTC system shall be determined and reported as follows: 

(i) The traffic density threshold of 5 million gross tons shall be based upon calendar year 

2008 gross tonnage, except to the extent that traffic may fall below 5 million gross tons for two 

consecutive calendar years and a PTCIP or an RFA reflecting this change is filed and approved 

under paragraph (b)(4) of this section and, if applicable, § 236.1021. 

(ii) The presence or absence of any quantity of PIH hazardous materials shall be determined 

by whether one or more cars containing such product(s) was transported over the track segment 

in calendar year 2008 or prior to the filing of the PTCIP, except to the extent that the PTCIP or 

RFA justifies, under paragraph (b)(4) of this section, removal of the subject track segment from 

the PTCIP listing of lines to be equipped. 

(3) Addition of track segments. To the extent increases in freight rail traffic occur subsequent 

to calendar year 2008 that might affect the requirement to install a PTC system on any line not 

yet equipped, the railroad shall seek to amend its PTCIP by promptly filing an RFA in 

accordance with § 236.1021. The following criteria apply: 

(i) If rail traffic exceeds 5 million gross tons in any year after 2008, the tonnage shall be 

calculated for the preceding two calendar years and if the total tonnage for those two calendar 

years exceeds 10 million gross tons, a PTCIP or its amendment is required. 

(ii) If PIH traffic is carried on a track segment as a result of a request for rail service or 

rerouting warranted under part 172 of this title, and if the line carries in excess of 5 million gross 

tons of rail traffic as determined under this paragraph, a PTCIP or its amendment is required. 

This does not apply when temporary rerouting is authorized in accordance with paragraph (g) of 

this section. 

(iii) Once a railroad is notified by FRA that its RFA filed in accordance with this paragraph 

has been approved, the railroad shall equip the line with the applicable PTC system by December 

31, 2015, or within 24 months, whichever is later. 

(4) Exclusion or removal of track segments from PTC baseline. (i) Routing changes. In a 

PTCIP or an RFA, a railroad may request review of the requirement to install PTC on a track 

segment where a PTC system is otherwise required by this section, but has not yet been installed, 

based upon changes in rail traffic such as reductions in total traffic volume or cessation of 

passenger or PIH service. Any such request shall be accompanied by estimated traffic 

projections for the next 5 years (e.g., as a result of planned rerouting, coordinations, or location 

of new business on the line). Where the request involves prior or planned rerouting of PIH 
236-207 

traffic, the railroad must provide a supporting analysis that takes into consideration the 

requirements of subpart I, part 172 of this title, assuming the subject route and each practicable 

alternative route to be PTC-equipped, and including any interline routing impacts. 

(A) FRA will approve the exclusion if, based upon data in the docket of the proceeding, FRA 

finds that it would be consistent with safety as further provided in this paragraph. 

(1) In the case of a requested exclusion based on cessation of passenger service or a decline 

in gross tonnage below 5 million gross tons as computed over a 2-year period, the removal will 

be approved absent special circumstances as set forth in writing (e.g., because of anticipated 

traffic growth in the near future). 

(2) In the case of current or planned cessation of PIH materials traffic over a track segment, 

FRA will approve an exclusion of a line from the PTCIP if the railroad satisfies the requirements 

of § 236.1020. 

(B) [Reserved] 

(ii) Lines with de minimis PIH risk. (A) In a PTCIP or RFA, a railroad may request review 

of the requirement to install PTC on a low density track segment where a PTC system is 

otherwise required by this section, but has not yet been installed, based upon the presence of a 

minimal quantity of PIH hazardous materials (less than 100 cars per year, loaded and residue). 

Any such request shall be accompanied by estimated traffic projections for the next 5 years (e.g., 

as a result of planned rerouting, coordinations, or location of new business on the line). Where 

the request involves prior or planned rerouting of PIH traffic, the railroad must provide the 

information and analysis identified in paragraph (b)(4)(i) of this section. The submission shall 

also include a full description of potential safety hazards on the segment of track and fully 

describe train operations over the line. This provision is not applicable to lines segments used by 

intercity or commuter passenger service. 

(B) Absent special circumstances related to specific hazards presented by operations on the 

line segment, FRA will approve a request for relief under this paragraph for a rail line segment: 

(1) Consisting exclusively of Class 1 or 2 track as described in part 213 of this title; 

(2) That carries less than 15 million gross tons annually; 

(3) Has a ruling grade of less than 1 percent; and 

(4) On which any train transporting a car containing PIH materials (including a residue car) 

is operated under conditions of temporal separation from other trains using the line segment as 

documented by a temporal separation plan accompanying the request. As used in this paragraph, 

“temporal separation” has the same meaning given by § 236.1019(e), except that the separation 

addressed is the separation of a train carrying any number of cars containing PIH materials from 

other freight trains. 

(C) FRA will also consider, and may approve, requests for relief under this paragraph for 

additional line segments where each such segment carries less than 15 million gross tons 

annually and where it is established to the satisfaction of the Associate Administrator that risk 

mitigations will be applied that will ensure that risk of a release of PIH materials is negligible. 

(D) Failure to submit sufficient information will result in the denial of any request under this 

paragraph (b)(4)(ii). If the request is granted, on and after the date the line would have otherwise 

been required to be equipped under the schedule contained in the PTCIP and approved by FRA, 

operations on the line shall be conducted in accordance with any conditions attached to the grant, 

including implementation of proposed mitigations as applicable. 

(5) Line sales. FRA does not approve removal of a line from the PTCIP exclusively based 

upon a representation that a track segment will be abandoned or sold to another railroad. In the 

event a track segment is approved for abandonment or transfer by the Surface Transportation 

Board, FRA will review at the request of the transferring and acquiring railroads whether the 

requirement to install PTC on the line should be removed given all of the circumstances, 

including expected traffic and hazardous materials levels, reservation of trackage or haulage 
236-208 

rights by the transferring railroad, routing analysis under part 172 of this chapter, commercial 

and real property arrangements affecting the transferring and acquiring railroads post-transfer, 

and such other factors as may be relevant to continue safe operations on the line. If FRA denies 

the request, the acquiring railroad shall install the PTC system on the schedule provided in the 

transferring railroad’s PTCIP, without regard to whether it is a Class I railroad. 

(6) New rail passenger service. No new intercity or commuter rail passenger service shall 

commence after December 31, 2015, until a PTC system certified under this subpart has been 

installed and made operative. 

(c) Hazard detectors. (1) All hazard detectors integrated into a signal or train control system 

on or after October 16, 2008, shall be integrated into PTC systems required by this subpart; and 

their warnings shall be appropriately and timely enforced as described in the applicable PTCSP. 

(2) The applicable PTCSP must provide for receipt and presentation to the locomotive 

engineer and other train crew members of warnings from any additional hazard detectors using 

the PTC data network, onboard displays, and audible alerts. If the PTCSP so provides, the action 

to be taken by the system and by the crew members shall be specified. 

(3) The PTCDP (as applicable) and PTCSP for any new service described in § 236.1007 to 

be conducted above 90 miles per hour shall include a hazard analysis describing the hazards 

relevant to the specific route(s) in question (e.g., potential for track obstruction due to events 

such as falling rock or undermining of the track structure due to high water or displacement of a 

bridge over navigable waters), the basis for decisions concerning hazard detectors provided, and 

the manner in which such additional hazard detectors will be interfaced with the PTC system. 

(d) Event recorders. (1) Each lead locomotive, as defined in part 229, of a train equipped 

and operating with a PTC system required by this subpart must be equipped with an operative 

event recorder, which shall: 

(i) Record safety-critical train control data routed to the locomotive engineer’s display that 

the engineer is required to comply with; 

(ii) Specifically include text messages conveying mandatory directives, maximum authorized 

speeds, PTC system brake warnings, PTC system brake enforcements, and the state of the PTC 

system (e.g., cut in, cut out, active, or failed); and 

(iii) Include examples of how the captured data will be displayed during playback along with 

the format, content, and data retention duration requirements specified in the PTCSP submitted 

and approved pursuant to this paragraph. If such train control data can be calibrated against 

other data required by this part, it may, at the election of the railroad, be retained in a separate 

memory module. 

(2) Each lead locomotive, as defined in part 229, manufactured and in service after October 

1, 2009, that is equipped and operating with a PTC system required by this subpart, shall be 

equipped with an event recorder memory module meeting the crash hardening requirements of § 

229.135 of this chapter. 

(3) Nothing in this subpart excepts compliance with any of the event recorder requirements 

contained in § 229.135 of this chapter. 

(e) Switch position. The following requirements apply with respect to determining proper 

switch position under this section. When a main line switch position is unknown or improperly 

aligned for a train’s route in advance of the train’s movement, the PTC system will provide 

warning of the condition associated with the following enforcement: 

(1) A PTC system shall enforce restricted speed over any switch: 

(i) Where train movements are made with the benefit of the indications of a wayside or cab 

signal system or other similar appliance, method, device, or system of equivalent safety proposed 

to FRA and approved by the Associate Administrator in accordance with this part; and 

(ii) Where wayside or cab signal system or other similar appliance, method, device, or 

system of equivalent safety, requires the train to be operated at restricted speed. 
236-209 

(2) A PTC system shall enforce a positive stop short of any main line switch, and any switch 

on a siding where the allowable speed is in excess of 20 miles per hour, if movement of the train 

over the switch: 

(i) Is made without the benefit of the indications of a wayside or cab signal system or other 

similar appliance, method, device, or system of equivalent safety proposed to FRA and approved 

by the Associate Administrator in accordance with this part; or 

(ii) Would create an unacceptable risk. Unacceptable risk includes conditions when 

traversing the switch, even at low speeds, could result in direct conflict with the movement of 

another train (including a hand-operated crossover between main tracks, a hand-operated 

crossover between a main track and an adjoining siding or auxiliary track, or a hand-operated 

switch providing access to another subdivision or branch line, etc.). 

(3) A PTC system required by this subpart shall be designed, installed, and maintained to 

perform the switch position detection and enforcement described in paragraphs (e)(1) and (e)(2) 

of this section, except as provided for and justified in the applicable, FRA approved PTCDP or 

PTCSP. 

(4) The control circuit or electronic equivalent for all movement authorities over any 

switches, movable-point frogs, or derails shall be selected through circuit controller or 

functionally equivalent device operated directly by the switch points, derail, or by switch locking 

mechanism, or through relay or electronic device controlled by such circuit controller or 

functionally equivalent device, for each switch, movable-point frog, or derail in the route 

governed. Circuits or electronic equivalent shall be arranged so that any movement authorities 

less restrictive than those prescribed in paragraphs (e)(1) and (e)(2) of this section can only be 

provided when each switch, movable-point frog, or derail in the route governed is in proper 

position, and shall be in accordance with subparts A through G of this part, unless it is otherwise 

provided in a PTCSP approved under this subpart. 

(f) Train-to-train collision. A PTC system shall be considered to be configured to prevent 

train-to-train collisions within the meaning of paragraph (a) of this section if trains are required 

to be operated at restricted speed and if the onboard PTC equipment enforces the upper limits of 

the railroad’s restricted speed rule (15 or 20 miles per hour). This application applies to: 

(1) Operating conditions under which trains are required by signal indication or operating 

rule to: 

(i) Stop before continuing; or 

(ii) Reduce speed to restricted speed and continue at restricted speed until encountering a 

more favorable indication or as provided by operating rule. 

(2) Operation of trains within the limits of a joint mandatory directive. 

(g) Temporary rerouting. A train equipped with a PTC system as required by this subpart 

may be temporarily rerouted onto a track not equipped with a PTC system and a train not 

equipped with a PTC system may be temporarily rerouted onto a track equipped with a PTC 

system as required by this subpart in the following circumstances: 

(1) Emergencies. In the event of an emergency—including conditions such as derailment, 

flood, fire, tornado, hurricane, earthquake, or other similar circumstance outside of the railroad’s 

control—that would prevent usage of the regularly used track if: 

(i) The rerouting is applicable only until the emergency condition ceases to exist and for no 

more than 14 consecutive calendar days, unless otherwise extended by approval of the Associate 

Administrator; 

(ii) The railroad provides written or telephonic notification to the applicable Regional 

Administrator of the information listed in paragraph (i) of this section within one business day of 

the beginning of the rerouting made in accordance with this paragraph; and 
236-210 

(iii) The conditions contained in paragraph (j) of this section are followed. 

(2) Planned maintenance. In the event of planned maintenance that would prevent usage of 

the regularly used track if: 

(i) The maintenance period does not exceed 30 days; 

(ii) A request is filed with the applicable Regional Administrator in accordance with 

paragraph (i) of this section no less than 10 business days prior to the planned rerouting; and 

(iii) The conditions contained in paragraph (j) of this section are followed. 

(h) Rerouting requests. (1) For the purposes of paragraph (g)(2) of this section, the rerouting 

request shall be self-executing unless the applicable Regional Administrator responds with a 

notice disapproving of the rerouting or providing instructions to allow rerouting. Such 

instructions may include providing additional information to the Regional Administrator or 

Associate Administrator prior to the commencement of rerouting. Once the Regional 

Administrator responds with a notice under this paragraph, no rerouting may occur until the 

Regional Administrator or Associate Administrator provides his or her approval. 

(2) In the event the temporary rerouting described in paragraph (g)(2) of this section is to 

exceed 30 consecutive calendar days: 

(i) The railroad shall provide a request in accordance with paragraphs (i) and (j) of this 

section with the Associate Administrator no less than 10 business days prior to the planned 

rerouting; and 

(ii) The rerouting shall not commence until receipt of approval from the Associate 

Administrator. 

(i) Content of rerouting request. Each notice or request referenced in paragraph (g) and (h) 

of this section must indicate: 

(1) The dates that such temporary rerouting will occur; 

(2) The number and types of trains that will be rerouted; 

(3) The location of the affected tracks; and 

(4) A description of the necessity for the temporary rerouting. 

(j) Rerouting conditions. Rerouting of operations under paragraph (g) of this section may 

occur under the following conditions: 

(1) Where a train not equipped with a PTC system is rerouted onto a track equipped with a 

PTC system, or a train not equipped with a PTC system that is compatible and functionally 

responsive to the PTC system utilized on the line to which the train is being rerouted, the train 

shall be operated in accordance with § 236.1029; or 

(2) Where any train is rerouted onto a track not equipped with a PTC system, the train shall 

be operated in accordance with the operating rules applicable to the line on which the train is 

rerouted. 

(k) Rerouting cessation. The applicable Regional Administrator may order a railroad to 

cease any rerouting provided under paragraph (g) or (h) of this section. 

Application:

A PTC system shall prevent train-to-train collisions, overspeed derailments, incursions into work 

limits without permission, or the movement of a train through a main line switch in the improper 

position. It shall include safety-critical integration of all authorities and signal indications. It 

shall provide appropriate warning or enforcement when a derail or switch is in the wrong 

position, a highway-rail grade crossing warning system malfunction is reported, a movable 

bridge is not in the proper position, or a hazard detector detects an unsafe condition. It shall also 

limit the speed of freight trains to 49 mph and passenger trains to 59 mph in areas without broken 

rail protection. 
236-211 

A PTC system will be installed on Class I railroad main lines over which any quantity of PIH 

material is transported or on any railroad lines where regularly scheduled passenger service is 

provided. There are specific requirements for the addition, exclusion, or removal of a PTC 

system along any track, or the re-routing of trains. Requests must be provided in accordance 

with the regulations. 

CLASSIFICATION OF DEFECTS 

§ 236.1005.A1 Failure of the PTC system to reliably and functionally prevent train-to-train 

collisions. 

§ 236.1005.A2 Alternative arrangements to reliably and functionally prevent train-to-train 

collisions not provided as specified in the PTCSP. 

§ 236.1005.A3 Alternative arrangements specified in the PTCSP to reliably and functionally 

prevent train-to-train collisions fail provide an equivalent level of safety. 

§ 236.1005.A4 Interlocking signal arrangement in accordance with the requirements of 

Subparts a – g not provided at a rail-to-rail at-grade crossing with at least one 

PTC route. 

§ 236.1005.A5 PTC enforced stop not provided on PTC routes at a rail-to-rail at-grade crossing. 

§ 236.1005.A6 Technology, other than full PTC, providing positive stop enforcement or a splitpoint derail incorporated into the signal system, not provided for a non-PTC 

route intersecting a PTC route with speed limit greater than 40 miles per hour at 

a rail-to-rail at-grade crossing. 

§ 236.1005.A7 Speed not limited to 20 mph on non-PTC route approaching a rail-to-rail atgrade crossing with at least one intersecting PTC route where the maximum 

speed is greater than 40 mph. 

§ 236.1005.A8 Split-point derail not incorporated into the signal system on non-PTC route 

approaching a rail-to-rail at-grade crossing with at least one intersecting PTC 

route where the maximum speed is greater than 40 mph. 

§ 236.1005.A9 Positive stop not enforced by other than full PTC technology used on non-PTC 

intersecting route approaching a rail-to-rail at-grade crossing with at least one 

PTC route where the maximum speed is greater than 40 mph. 

§ 236.1005.A10 Failure of the PTC system to reliably and functionally prevent overspeed 

derailments. 

§ 236.1005.A11 Failure of the PTC system to reliably and functionally enforce railroad civil 

engineering speed restrictions. 

§ 236.1005.A12 Failure of the PTC system to reliably and functionally enforce temporary speed 

restrictions. 
236-212 

§ 236.1005.A13 Failure of the PTC system to reliably and functionally enforce the most 

restrictive speed restriction within a track segment. 

§ 236.1005.A14 Failure of the PTC system to reliably and functionally prevent incursions into 

established work zone limits where appropriate authority and/or verification has 

not been received. 

§ 236.1005.A15 Failure of the PTC system to integrate, within the system, electronic authority 

and/or verification to enter established work zone limits. 

§ 236.1005.A16 Failure of the PTC system to enforce speed restrictions within established work 

zone limits. 

§ 236.1005.A17 Failure of the PTC system to reliably and functionally prevent the movement of 

a train through a main line switch in the improper position. 

§ 236.1005.A18 Failure of the PTC system to include safety-critical integration of all authorities 

and/or indications of a wayside signal system, cab signal system, other similar 

appliance, method, device, or system of equivalent safety. 

§ 236.1005.A19 Failure of the PTC system to provide warning and/or enforcement of all 

authorities and indications of a wayside signal system, cab signal system, other 

similar appliance, method, device, or system of equivalent safety. 

§ 236.1005.A20 Failure of the PTC system to provide warning and/or enforcement when a 

switch or derail protecting access to the main line is not in its protecting or 

derailing position. 

§ 236.1005.A21 Failure of the PTC system to provide warning and/or enforcement when a 

mandatory directive is issued associated with a malfunctioning highway-rail 

grade crossing warning system. 

§ 236.1005.A22 Failure of the PTC system to provide warning and/or enforcement when an 

after-arrival mandatory directive has been issued and the train or trains to be 

waited on have not passed the location of the receiving train. 

§ 236.1005A23 Failure of the PTC system to provide warning and/or enforcement when any 

movable bridge within the route ahead is not in a position to allow permissive 

indication for train movements. 

§ 236.1005.A24 Failure of the PTC system to provide warning and/or enforcement when a 

hazard detector, integrated into the PTC system, detects an unsafe condition or 

transmits an alarm. 

§ 236.1005.A25 Failure of the PTC system to limit the speed of passenger trains to 59 mph in 

areas without broken rail protection or equivalent safeguards. 

§ 236.1005.A26 Failure of the PTC system to limit the speed of freight trains to 49 mph in areas 

without broken rail protection or equivalent safeguards. 
236-213 

§ 236.1005.B1 Failure to implement a PTC system on a track segment where PTC is required 

prior to December 31, 2015. 

§ 236.1005.B2 Commencement of revenue service of a PTC system prior to obtaining system 

certification. 

§ 236.1005.B3 Failure to install PTC on a track segment on which freight rail traffic subsequent 

to calendar year 2008 has increased to levels requiring the implementation of 

PTC. 

§ 236.1005.B4 Failure to amend a PTCIP, by promptly filing an RFA, to include implementing 

PTC on a track segment on which freight rail traffic subsequent to calendar year 

2008 has increased to levels requiring the implementation of PTC. 

§ 236.1005.B5 Failure to implement PTC on a track segment included in an FRA approved 

RFA by December 31, 2015 or within 24 months, whichever is later. 

§ 236.1005.B6 Failure to obtain FRA approval, by an RFA and amended PTCIP, to exclude a 

track segment from PTC implementation due to routing changes. 

§ 236.1005.B7 Failure to obtain FRA approval, by an RFA and amended PTCIP, to exclude a 

track segment from PTC implementation due to decreased freight traffic. 

§ 236.1005.B8 Failure to obtain FRA approval, by an RFA and amended PTCIP, to exclude a 

track segment from PTC implementation due to line sales. 

§ 236.1005.B9 Failure to install an FRA certified PTC system prior to commencing a new 

intercity or commuter rail passenger service after December 31, 2015. 

§ 236.1005.C1 Failure to integrate a hazard detector into a PTC system that was integrated into 

a signal or train control system on or after October 16, 2008. 

§ 236.1005.C2 Failure of a PTC system integrated hazard detector to timely and/or 

appropriately enforce warnings as described in the PTCSP. 

§ 236.1005.D1 Lead locomotive of a train required to be PTC equipped not equipped with an 

operative event recorder. 

§ 236.1005.D2 Failure of the event recorder in the lead locomotive of a train required to be 

PTC equipped to record the locomotive engineer’s safety-critical train control 

data that the engineer is required to comply with. 

§ 236.1005.D3 Failure of the event recorder in the lead locomotive of a train required to be 

PTC equipped to record text messages conveying mandatory directives, 

maximum authorized speeds, PTC system brake warnings, PTC system brake 

enforcements, or the state of the PTC system. 
236-214 

§ 236.1005.D4 Failure of the event recorder in the lead locomotive of a train required to be 

PTC equipped, manufactured and in service after October 1, 2009, not equipped 

with a crash hardened memory module. 

§ 236.1005.E1 Failure to design, install, and/or maintain a required PTC system to perform 

switch point detection and enforcement except as provided for in an FRA 

approved PTCDP or PTCSP. 

§ 236.1005.E2 Failure of the PTC system, supplemented by indications of a wayside or cab 

signal system, or similar appliance, method, device, or system of equivalent 

safety, to provide warning and/or enforce restricted speed over any main line 

switch when the switch position is unknown or improperly lined for a train’s 

route in advance of the train’s movement. 

§ 236.1005.E3 Failure of the PTC system to provide warning and/or enforce restricted speed 

over any switch where indications of a wayside or cab signal system, or similar 

appliance, method, device, or system of equivalent safety, requires the train to 

be operated at restricted speed. 

§ 236.1005.E4 Failure of the PTC system, without the indications of a wayside or cab signal 

system, or similar appliance, method, device, or system of equivalent safety, to 

provide warning and/or enforce a positive stop short of any mainline switch, or 

any switch on a siding where the allowable speed is in excess of 20 mph when 

the switch position is unknown or improperly lined for a train’s route in advance 

of the train’s movement. 

§ 236.1005.E5 Failure of the PTC system to provide warning and/or enforce a positive stop 

short of any mainline switch, or any switch on a siding where the allowable 

speed is in excess of 20 mph and would create an unacceptable risk. 

§ 236.1005.G1 PTC required equipped trains rerouted to a non-PTC equipped track without 

approval or just cause. 

§ 236.1005.G2 Non-PTC equipped trains rerouted to a PTC required track without approval or 

just cause. 

§ 236.1005.G3 Emergency rerouting of PTC required equipped trains to a non-PTC equipped 

track in excess of 14 consecutive calendar days without FRA approval. 

§ 236.1005.G4 Emergency rerouting of non-PTC equipped trains to a PTC required track in 

excess of 14 consecutive calendar days without FRA approval. 

§ 236.1005.G5 Emergency rerouting of PTC required equipped trains to a non-PTC equipped 

track after the emergency condition ceases. 

§ 236.1005.G6 Emergency rerouting of non-PTC equipped trains to a PTC required track after 

the emergency condition ceases. 

§ 236.1005.G7 Failure of the railroad to provide written or telephonic notification to the 

applicable FRA regional administrator within one business day after 

commencing emergency rerouting operations. 
236-215 

§ 236.1005.G8 Failure to provide the required information in the written or telephonic 

temporary rerouting request. 

§ 236.1005.G9 Planned maintenance rerouting of PTC required equipped trains to a non-PTC 

equipped track in excess of 30 consecutive calendar days without approval. 

§ 236.1005.G10 Planned maintenance rerouting of non-PTC equipped trains to a PTC required 

track in excess of 30 consecutive calendar days without approval. 

§ 236.1005.G11 Failure to provide written or telephonic notification to the applicable FRA 

regional administrator at least 10 business days prior to the planned 

maintenance rerouting operations beginning. 

§ 236.1005.G12 Commencing planned maintenance rerouting operations without FRA approval. 

§ 236.1005.G13 Failure to operate non-PTC equipped trains temporarily rerouted to a PTC 

required track in accordance with § 236.1029. 

§ 236.1005.G14 Failure to cease temporary rerouting operations per FRA order. 

§ 236.1006 Equipping locomotives operating in PTC territory. 

(a) Except as provided in paragraph (b) of this section, each train operating on any track 

segment equipped with a PTC system shall be controlled by a locomotive equipped with an 

onboard PTC apparatus that is fully operative and functioning in accordance with the applicable 

PTCSP approved under this subpart. 

(b) Exceptions. (1) Prior to December 31, 2015, each railroad required to install PTC shall 

include in its PTCIP specific goals for progressive implementation of onboard systems and 

deployment of PTC-equipped locomotives such that the safety benefits of PTC are achieved 

through incremental growth in the percentage of controlling locomotives operating on PTC lines 

that are equipped with operative PTC onboard equipment. The PTCIP shall include a brief but 

sufficient explanation of how those goals will be achieved, including assignment of 

responsibilities within the organization. The goals shall be expressed as the percentage of trains 

operating on PTC-equipped lines that are equipped with operative onboard PTC apparatus 

responsive to the wayside, expressed as an annualized (calendar year) percentage for the railroad 

as a whole. 

(2) Each railroad shall adhere to its PTCIP and shall report, on April 16, of 2011, 2012, 2013, 

and 2014, its progress toward achieving the goals set under paragraph (b)(1) of this section. In 

the event any annual goal is not achieved, the railroad shall further report the actions it is taking 

to ensure achievement of subsequent annual goals. 

(3) On and after December 31, 2015, a train controlled by a locomotive with an onboard PTC 

apparatus that has failed en route is permitted to operate in accordance with § 236.1029. 

(4) A train operated by a Class II or Class III railroad, including a tourist or excursion 

railroad, and controlled by a locomotive not equipped with an onboard PTC apparatus is 

permitted to operate on a PTC-operated track segment: 

(i) That either: 

(A) Has no regularly scheduled intercity or commuter passenger rail traffic; or 

(B) Has regularly scheduled intercity or commuter passenger rail traffic and the applicable 

PTCIP permits the operation of a train operated by a Class II or III railroad and controlled by a 
236-216 

locomotive not equipped with an onboard PTC apparatus; 

(ii) Where operations are restricted to four or less such unequipped trains per day, whereas a 

train conducting a “turn” operation (e.g., moving to a point of interchange to drop off or pick up 

cars and returning to the track owned by a Class II or III railroad) is considered two trains for 

this purpose; and 

(iii) Where each movement shall either: 

(A) Not exceed 20 miles in length; or 

(B) To the extent any movement exceeds 20 miles in length, such movement is not permitted 

without the controlling locomotive being equipped with an onboard PTC system after December 

31, 2020, and each applicable Class II or III railroad shall report to FRA its progress in 

equipping each necessary locomotive with an onboard PTC apparatus to facilitate continuation of 

the movement. The progress reports shall be filed not later than December 31, 2017 and, if all 

necessary locomotives are not yet equipped, on December 31, 2019. 

(c) When a train movement is conducted under the exceptions described in paragraph (b)(4) 

of this section, that movement shall be made in accordance with § 236.1029. 

Application: 

Each train operating on any track segment equipped with a PTC system shall be controlled by a 

locomotive equipped with an onboard PTC apparatus. There are certain exceptions which are as 

defined in this subsection. 

CLASSIFICATION OF DEFECTS 

§ 236.1006.A1 Operating a controlling locomotive in PTC territory without a required and 

operative PTC onboard apparatus on and/or after December 31, 2015. 

§ 236.1006.B1 Failure of a railroad required to implement PTC to adhere to its PTCIP. 

§ 236.1006.B2 Failure to report as prescribed by this section. 

§ 236.1006.B3 Failure of a railroad required to implement PTC to report actions taken to ensure 

achievement of subsequent annual goals after failing a previous annual goal. 

§ 236.1006.B4 Trains of a Class II, Class III, tourist, and/or excursion railroad, controlled by a 

locomotives not equipped with an onboard PTC apparatus, operating on PTCequipped track with regularly scheduled intercity or commuter passenger traffic 

when the applicable PTCIP does not permit such operations. 

§ 236.1006.B5 Trains of a Class II, Class III, tourist, and/or excursion railroad, controlled by 

locomotives not equipped with an onboard PTC apparatus, operating on PTCequipped track in excess of four trains per day. 

§ 236.1006.B6 Trains of a Class II, Class III, tourist, and/or excursion railroad, controlled by 

locomotives not equipped with an onboard PTC apparatus, operating more than 

20 miles on PTC equipped track after December 31, 2020. 
236-217 

§ 236.1007 Additional requirements for high-speed service. 

(a) A PTC railroad that conducts a passenger operation at or greater than 60 miles per hour or 

a freight operation at or greater than 50 miles per hour shall have installed a PTC system 

including or working in concert with technology that includes all of the safety-critical functional 

attributes of a block signal system meeting the requirements of this part, including appropriate 

fouling circuits and broken rail detection (or equivalent safeguards). 

(b) In addition to the requirements of paragraph (a) of this section, a host railroad that 

conducts a freight or passenger operation at more than 90 miles per hour shall: 

(1) Have an approved PTCSP establishing that the system was designed and will be operated 

to meet the fail-safe operation criteria described in Appendix C to this part; and 

(2) Prevent unauthorized or unintended entry onto the main line from any track not equipped 

with a PTC system compliant with this subpart by placement of split-point derails or equivalent 

means integrated into the PTC system; and 

(3) Comply with § 236.1029(c). 

(c) In addition to the requirements of paragraphs (a) and (b) of this section, a host railroad 

that conducts a freight or passenger operation at more than 125 miles per hour shall have an 

approved PTCSP accompanied by a document (“HSR-125”) establishing that the system: 

(1) Will be operated at a level of safety comparable to that achieved over the 5 year period 

prior to the submission of the PTCSP by other train control systems that perform PTC functions 

required by this subpart, and which have been utilized on high-speed rail systems with similar 

technical and operational characteristics in the United States or in foreign service, provided that 

the use of foreign service data must be approved by the Associate Administrator before submittal 

of the PTCSP; and 

(2) Has been designed to detect incursions into the right-of-way, including incidents 

involving motor vehicles diverting from adjacent roads and bridges, where conditions warrant. 

(d) In addition to the requirements of paragraphs (a) through (c) of this section, a host 

railroad that conducts a freight or passenger operation at more than 150 miles per hour, which is 

governed by a Rule of Particular Applicability, shall have an approved PTCSP accompanied by a 

HSR-125 developed as part of an overall system safety plan approved by the Associate 

Administrator. 

(e) A railroad providing existing high-speed passenger service may request in its PTCSP that 

the Associate Administrator excuse compliance with one or more requirements of this section 

upon a showing that the subject service has been conducted with a high level of safety. 

Application: 

A PTC railroad that conducts a passenger operation at or greater than 60 mph or a freight 

operation at or greater than 50 mph shall have a block signal system installed in addition to a 

PTC system. If a railroad operates at more than 90 mph it will include the above mentioned 

system in addition to providing intrusion detection and a means to prevent unauthorized entry 

along with other requirements as defined in this subpart. There are further requirements for 

railroads operating at over 150 mph. 

CLASSIFICATION OF DEFECTS 

§ 236.1007.A1 Operation of passenger trains on non-PTC equipped territory at speeds equal to 

or greater than 60 mph. 

§ 236.1007.A2 Operation of passenger trains at speed equal to or greater than 60 mph on PTC 
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system not integrated with technology that includes all the safety-critical 

functional attributes of a block signal system meeting the requirements of this 

part. 

§ 236.1007.A3 Operation of freight trains on non-PTC equipped territory at speeds equal to or 

greater than 50 mph. 

§ 236.1007.A4 Operation of freight trains at speed equal to or greater than 50 mph on PTC 

system not integrated with technology that includes all the safety-critical 

functional attributes of a block signal system meeting the requirements of this 

part. 

§ 236.1007.B1 Failure to fully implement incursion protection where required. 

§ 236.1007.B2 Operation of trains at speeds greater than 90 mph on PTC system not designed 

per appendix C. 

§ 236.1007.C1 Operation of trains at speeds greater than 125 mph without an approved PTCSP 

accompanied by an HSR-125 document. 

§ 236.1007.C2 Operation of trains at speeds greater than 125 mph at a level of safety less than 

that achieved over the 5 year period prior to the submission of the PTCSP by 

other train control systems that perform PTC functions required by this subpart. 

§ 236.1007.C3 Operation of trains at speeds greater than 125 mph at a level of safety less than 

that achieved over the 5 year period prior to the submission of the PTCSP by 

other train control systems that perform PTC functions that have been utilized 

on high-speed rail systems with similar technical and operational characteristics 

in the united states or in foreign service. 

§ 236.1007.C4 Operation of trains at speeds greater than 125 mph on PTC system without 

incursion detection. 

§ 236.1007.D1 Operation of trains at speeds greater than 150 mph not in accordance with the 

rule of particular applicability. 

§ 236.1009 Procedural requirements. 

(a) PTC Implementation Plan (PTCIP). (1) By April 16, 2010, each host railroad that is 

required to implement and operate a PTC system in accordance with § 236.1005(b) shall develop 

and submit in accordance with § 236.1011(a) a PTCIP for implementing a PTC system required 

under § 236.1005. Filing of the PTCIP shall not exempt the required filings of an NPI, PTCSP, 

PTCDP, or Type Approval. 

(2) After April 16, 2010, a host railroad shall file: 

(i) A PTCIP if it becomes a host railroad of a main line track segment for which it is required 

to implement and operate a PTC system in accordance with § 236.1005(b); or 

(ii) A request for amendment (“RFA”) of its current and approved PTCIP in accordance with 

§ 236.1021 if it intends to: 

(A) Initiate a new category of service (i.e., passenger or freight); or 

(B) Add, subtract, or otherwise materially modify one or more lines of railroad for which 
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installation of a PTC system is required. 

(3) The host and tenant railroad(s) shall jointly file a PTCIP that addresses shared track: 

(i) If the host railroad is required to install and operate a PTC system on a segment of its 

track; and 

(ii) If the tenant railroad that shares the same track segment would have been required to 

install a PTC system if the host railroad had not otherwise been required to do so. 

(4) If railroads required to file a joint PTCIP are unable to jointly file a PTCIP in accordance 

with paragraphs (a)(1) and (a)(3) of this section, then each railroad shall: 

(i) Separately file a PTCIP in accordance with paragraph (a)(1); 

(ii) Notify the Associate Administrator that the subject railroads were unable to agree on a 

PTCIP to be jointly filed; 

(iii) Provide the Associate Administrator with a comprehensive list of all issues not in 

agreement between the railroads that would prevent the subject railroads from jointly filing the 

PTCIP; and 

(iv) Confer with the Associate Administrator to develop and submit a PTCIP mutually 

acceptable to all subject railroads. 

(b) Type Approval. Each host railroad, individually or jointly with others such as a tenant 

railroad or system supplier, shall file prior to or simultaneously with the filing made in 

accordance with paragraph (a) of this section: 

(1) An unmodified Type Approval previously issued by the Associate Administrator in 

accordance with § 236.1013 or § 236.1031(b) with its associated docket number; 

(2) A PTCDP requesting a Type Approval for: 

(i) A PTC system that does not have a Type Approval; or 

(ii) A PTC system with a previously issued Type Approval that requires one or more 

variances; 

(3) A PTCSP subject to the conditions set forth in paragraph (c) of this section, with or 

without a Type Approval; or 

(4) A document attesting that a Type Approval is not necessary since the host railroad has no 

territory for which a PTC system is required under this subpart. 

(c) Notice of Product Intent (NPI). A railroad may, in lieu of submitting a PTCDP, or 

referencing an already issued Type Approval, submit an NPI describing the functions of the 

proposed PTC system. If a railroad elects to file an NPI in lieu of a PTCDP or referencing an 

existing Type Approval with the PTCIP, and the PTCIP is otherwise acceptable to the Associate 

Administrator, the Associate Administrator may grant provisional approval of the PTCIP. 

(1) A provisional approval of a PTCIP, unless otherwise extended by the Associate 

Administrator, is valid for a period of 270 days from the date of approval by the Associate 

Administrator. 

(2) The railroad must submit an updated PTCIP with either a complete PTCDP as defined in 

§236.1013(a), an updated PTCIP referencing an already approved Type Approval, or a full 

PTCSP within 270 days after the “Provisional Approval.” 

(i) Within 90 days of receipt of an updated PTCIP that was submitted with an NPI, the 

Associate Administrator will approve or disapprove of the updated PTCIP and notify in writing 

the affected railroad. If the updated PTCIP is not approved, the notification will include the 

plan’s deficiencies. Within 30 days of receipt of that notification, the railroad or other entity that 

submitted the plan shall correct all deficiencies and resubmit the plan in accordance with this 

section and § 236.1011, as applicable. 

(ii) If an update to a “Provisionally Approved” PTCIP is not received by the Associate 

Administrator by the end of the period indicated in this paragraph, the “Provisional Approval” 

given to the PTCIP is automatically revoked. The revocation is retroactive to the date the 

original PTCIP and NPI were first submitted to the Associate Administrator. 
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(d) PTCSP and PTC System Certification. The following apply to each PTCSP and PTC 

System Certification. 

(1) A PTC System Certification for a PTC system may be obtained by submitting an 

acceptable PTCSP. If the PTC system is the subject of a Type Approval, the safety case elements 

contained in the PTCDP may be incorporated by reference into the PTCSP, subject to 

finalization of the human factors analysis contained in the PTCDP. 

(2) Each PTCSP requirement under § 236.1015 shall be supported by information and 

analysis sufficient to establish that the requirements of this subpart have been satisfied. 

(3) If the Associate Administrator finds that the PTCSP and supporting documentation 

support a finding that the system complies with this part, the Associate Administrator may 

approve the PTCSP. If the Associate Administrator approves the PTCSP, the railroad shall 

receive PTC System Certification for the subject PTC system and shall implement the PTC 

system according to the PTCSP. 

(4) A required PTC system shall not: 

(i) Be used in service until it receives from FRA a PTC System Certification; and (ii) Receive 

a PTC System Certification unless FRA receives and approves an applicable: 

(A) PTCSP; or 

(B) Request for Expedited Certification (REC) as defined by § 236.1031(a). 

(e) Plan contents. (1) No PTCIP shall receive approval unless it complies with § 236.1011. 

No railroad shall receive a Type Approval or PTC System Certification unless the applicable 

PTCDP or PTCSP, respectively, comply with §§ 236.1013 and 236.1015, respectively. 

(2) All materials filed in accordance with this subpart must be in the English language, or 

have been translated into English and attested as true and correct. 

(3) Each filing referenced in this section may include a request for full or partial 

confidentiality in accordance with § 209.11 of this chapter. If confidentiality is requested as to a 

portion of any applicable document, then in addition to the filing requirements under § 209.11 of 

this chapter, the person filing the document shall also file a copy of the original unredacted 

document, marked to indicate which portions are redacted in the document’s confidential version 

without obscuring the original document’s contents. 

(f) Supporting documentation and information. (1) Issuance of a Type Approval or PTC 

System Certification is contingent upon FRA’s confidence in the implementation and operation 

of the subject PTC system. This confidence may be based on FRA-monitored field testing or an 

independent assessment performed in accordance with § 236.1035 or § 236.1017, respectively. 

(2) Upon request by FRA, the railroad requesting a Type Approval or PTC System 

Certification must engage in field testing or independent assessment performed in accordance 

with § 236.1035 or § 236.1017, respectively, to support the assertions made in any of the plans 

submitted under this subpart. These assertions include any of the plans’ content requirements 

under this subpart. 

(g) FRA conditions, reconsiderations, and modifications. (1) As necessary to ensure safety, 

FRA may attach special conditions to approving a PTCIP or issuing a Type Approval or PTC 

System Certification. 

(2) After granting a Type Approval or PTC System Certification, FRA may reconsider the 

Type Approval or PTC System Certification upon revelation of any of the following factors 

concerning the contents of the PTCDP or PTCSP: 

(i) Potential error or fraud; 

(ii) Potentially invalidated assumptions determined as a result of in-service experience or one 

or more unsafe events calling into question the safety analysis supporting the approval. 

(3) During FRA’s reconsideration in accordance with this paragraph, the PTC system may 

remain in use if otherwise consistent with the applicable law and regulations and FRA may 
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impose special conditions for use of the PTC system. 

(4) After FRA’s reconsideration in accordance with this paragraph, FRA may: 

(i) Dismiss its reconsideration and continue to recognize the existing FRA approved 

Type Approval or PTC System Certification; 

(ii) Allow continued operations under such conditions the Associate Administrator deems 

necessary to ensure safety; or 

(iii) Revoke the Type Approval or PTC System Certification and direct the railroad to cease 

operations where PTC systems are required under this subpart. 

(h) FRA access. The Associate Administrator, or that person’s designated representatives, 

shall be afforded reasonable access to monitor, test, and inspect processes, procedures, facilities, 

documents, records, design and testing materials, artifacts, training materials and programs, and 

any other information used in the design, development, manufacture, test, implementation, and 

operation of the system, as well as interview any personnel: 

(1) Associated with a PTC system for which a Type Approval or PTC System Certification 

has been requested or provided; or 

(2) To determine whether a railroad has been in compliance with this subpart. 

(i) Foreign regulatory entity verification. Information that has been certified under the 

auspices of a foreign regulatory entity recognized by the Associate Administrator may, at 

the Associate Administrator’s sole discretion, be accepted as independently Verified and 

Validated and used to support each railroad’s development of the PTCSP. 

(j) Processing times for PTCDP and PTCSP. (1) Within 30 days of receipt of a PTCDP or 

PTCSP, the Associate Administrator will either acknowledge receipt or acknowledge receipt and 

request more information. 

(2) To the extent practicable, considering the scope, complexity, and novelty of the product 

or change: 

(i) FRA will approve, approve with conditions, or deny the PTCDP within 60 days of the 

date on which the PTCDP was filed; 

(ii) FRA will approve, approve with conditions, or deny the PTCSP within 180 days of the 

date on which the PTCSP was filed; 

(iii) If FRA has not approved, approved with conditions, or denied the PTCDP or PTCSP 

within the 60-day or 180-day window, as applicable, FRA will provide the submitting party with 

a statement of reasons as to why the submission has not yet been acted upon and a projected 

deadline by which an approval or denial will be issued and any further consultations or inquiries 

will be resolved. 

Application:

This section defines the procedural requirements for a railroad to file the required documentation 

necessary to install a PTC system. It lists the necessary documents along with the timelines 

associated with their filing. It also lists the various options that a railroad has as it pertains to 

what type of system they intend to install. 

CLASSIFICATION OF DEFECTS 

§ 236.1009.A1 Failure to develop and/or submit a PTC implementation plan within the required 

time frame. 

§ 236.1009.A2 Failure to amend PTCIP when required. 
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§ 236.1009.A3 Failure of the host and tenant railroad(s) to file a joint PTCIP when required. 

§ 236.1009.A4 Failure of the host and/or tenant railroad(s) to file separate PTCIPs when unable 

to file a joint PTCIP. 

§ 236.1009.A5 Failure of the host and/or tenant railroad(s) to notify the Associate 

Administrator for Railroad Safety/Chief Safety Officer when unable to file a 

required joint PTCIP. 

§ 236.1009.A6 Failure of the host and/or tenant railroad(s), unable to file a joint PTCIP, to 

provide the Associate Administrator a comprehensive list of issues preventing 

the filing of a joint PTCIP. 

§ 236.1009.A7 Failure of the host and/or tenant railroad(s), unable to file a joint PTCIP, to 

confer with the Associate Administrator to develop and submit a PTCIP 

acceptable to all subject railroads. 

§ 236.1009.B1 Failure to file prior to or simultaneously with the PTCIP either a PTCDP or 

reference to an already issued Type Approval. 

§ 236.1009.B2 Failure to obtain Type Approval when required. 

§ 236.1009.C1 Failure to submit prior to or simultaneously with the PTCIP a NPI in lieu of 

either a PTCP or reference to an already issued Type Approval. 

§ 236.1009.C2 Failure to submit to FRA an updated PTCIP with a PTCDP, referenced Type 

Approval, or PTCSP within 270 days of being granted a Provisional Approval 

of a PTCIP. 

§ 236.1009.C3 Failure to update NPI. 

§ 236.1009.D1 Operation of PTC system prior to system certification. 

§ 236.1009.D2 Failure to implement PTC system in accordance to the PTCSP. 

§ 236.1009.E1 Failure to submit to FRA a PTCIP, NPI, PTCDP, or PTCSP, referencing a Type 

Approval, or filing a document attesting a Type Approval is not necessary, in 

the English language. 

§ 236.1009.F1 Failure to engage in field testing or conduct an independent assessment as 

requested by FRA. 

§ 236.1009.G1 Failure to abide to FRA special conditions attached to a PTCIP, Type Approval, 

or PTC system certification. 

§ 236.1009.H1 Failure to grant FRA reasonable access to monitor, test, inspect, and/or 

interview. 

§ 236.1009.I1 Information provided by a foreign regulatory entity, not recognized by FRA, 

used to support the development of a PTCSP. 
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§ 236.1011 PTC Implementation Plan content requirements. 

(a) Contents. A PTCIP filed pursuant to this subpart shall, at a minimum, describe: 

(1) The functional requirements that the proposed system must meet; 

(2) How the PTC railroad intends to comply with §§ 236.1009(c) and (d); 

(3) How the PTC system will provide for interoperability of the system between the host and 

all tenant railroads on the track segments required to be equipped with PTC systems under this 

subpart and: 

(i) Include relevant provisions of agreements, executed by all applicable railroads, in place to 

achieve interoperability; 

(ii) List all methods used to obtain interoperability; and 

(iii) Identify any railroads with respect to which interoperability agreements have not been 

achieved as of the time the plan is filed, the practical obstacles that were encountered that 

prevented resolution, and the further steps planned to overcome those obstacles; 

(4) How, to the extent practical, the PTC system will be implemented to address areas of 

greater risk to the public and railroad employees before areas of lesser risk; 

(5) The sequence and schedule in which track segments will be equipped and the basis for 

those decisions, and shall at a minimum address the following risk factors by track segment: 

(i) Segment traffic characteristics such as typical annual passenger and freight train volume 

and volume of poison- or toxic-by-inhalation (PIH or TIH) shipments (loads, residue); 

(ii) Segment operational characteristics such as current method of operation (including 

presence or absence of a block signal system), number of tracks, and maximum allowable train 

speeds, including planned modifications; and 

(iii) Route attributes bearing on risk, including ruling grades and extreme curvature; 

(6) The following information relating to rolling stock: 

(i) What rolling stock will be equipped with PTC technology; 

(ii) The schedule to equip that rolling stock by December 31, 2015; 

(iii) All documents and information required by § 236.1006; and 

(iv) Unless the tenant railroad is filing its own PTCIP, the host railroad’s PTCIP shall: 

(A) Attest that the host railroad has made a formal written request to each tenant railroad 

requesting identification of each item of rolling stock to be PTC system equipped and the date 

each will be equipped; and 

(B) Include each tenant railroad’s response to the host railroad’s written request made in 

accordance with paragraph (a)(6)(iv)(A) of this section; 

(7) The number of wayside devices required for each track segment and the installation 

schedule to complete wayside equipment installation by December 31, 2015; 

(8) Identification of each track segment on the railroad as mainline or non-mainline track. If 

the PTCIP includes an MTEA, as defined by § 236.1019, the PTCIP should identify the tracks 

included in the MTEA as main line track with a reference to the MTEA; 

(9) To the extent the railroad determines that risk-based prioritization required by paragraph 

(a)(4) of this section is not practical, the basis for this determination; and 

(10) The dates the associated PTCDP and PTCSP, as applicable, will be submitted to FRA in 

accordance with § 236.1009. 

(b) Additional Class I railroad PTCIP requirements. Each Class I railroad shall include: 

(1) In its PTCIP a strategy for full deployment of its PTC system, describing the criteria that 

it will apply in identifying additional rail lines on its own network, and rail lines of entities that it 

controls or engages in joint operations with, for which full or partial deployment of PTC 

technologies is appropriate, beyond those required to be equipped under this subpart. Such 

criteria shall include consideration of the policies established by 49 U.S.C. 20156 (railroad safety 
236-224 

risk reduction program), and regulations issued there under, as well as non-safety business 

benefits that may accrue. 

(2) In the Technology Implementation Plan of its Risk Reduction Program, when first 

required to be filed in accordance with 49 U.S.C. 20156 and any regulation promulgated there 

under, a specification of rail lines selected for full or partial deployment of PTC under the 

criteria identified in its PTCIP. 

(3) Nothing in this paragraph shall be construed to create an expectation or requirement that 

additional rail lines beyond those required to be equipped by this subpart must be equipped or 

that such lines will be equipped during the period of primary implementation ending December 

31, 2015. 

(4) As used in this paragraph, “partial implementation” of a PTC system refers to use, 

pursuant to subpart H of this part, of technology embedded in PTC systems that does not employ 

all of the functionalities required by this subpart. 

(c) FRA review. Within 90 days of receipt of a PTCIP, the Associate Administrator will 

approve or disapprove of the plan and notify in writing the affected railroad or other entity. If 

the PTCIP is not approved, the notification will include the plan’s deficiencies. Within 30 days 

of receipt of that notification, the railroad or other entity that submitted the plan shall correct all 

deficiencies and resubmit the plan in accordance with § 236.1009 and paragraph (a) of this 

section, as applicable. 

(d) Subpart H. A railroad that elects to install a PTC system when not required to do so may 

elect to proceed under this subpart or under subpart H of this part. 

(e) Upon receipt of a PTCIP, NPI, PTCDP, or PTCSP, FRA posts on its public web site 

notice of receipt and reference to the public docket in which a copy of the filing has been placed. 

FRA may 

consider any public comment on each document to the extent practicable within the time allowed 

by law and without delaying implementation of PTC systems. 

(f) The PTCIP shall be maintained to reflect the railroad’s most recent PTC deployment plans 

until all PTC system deployments required under this subpart are complete. 

Application:

This section describes the contents required within a railroad’s PTCIP. It includes the functional 

requirements, interoperability, the sequence and schedule in which track segments will be 

equipped, along with rolling stock information. It also lists any MTEA’s risk based prioritization, 

and other specific information as defined within the section. 

CLASSIFICATION OF DEFECTS 

§ 236.1011.A1 Failure to provide the required information in a PTCIP. 

§ 236.1011.B1 Failure of a class 1 railroad to include a strategy for full deployment of a PTC 

system within the PTCIP. 

§ 236.1011.C1 Failure to correct a deficient PTCIP within 30 days of notification by FRA. 

§ 236.1011.F1 Failure to maintain a PTCIP reflecting the most recent PTC deployment plans. 

§ 236.1011.F2 Failure to install a PTC system in accordance with Subpart I when so required. 

§ 236.1013 PTC Development Plan and Notice of Product Intent content requirements and 
236-225 

Type Approval. 

(a) For a PTC system to obtain a Type Approval from FRA, the PTCDP shall be filed in 

accordance with § 236.1009 and shall include: 

(1) A complete description of the PTC system, including a list of all PTC system components 

and their physical relationships in the subsystem or system; 

(2) A description of the railroad operation or categories of operations on which the PTC 

system is designed to be used, including train movement density (passenger, freight), operating 

speeds (including a thorough explanation of intended compliance with § 236.1007), track 

characteristics, and railroad operating rules; 

(3) An operational concepts document, including a list with complete descriptions of all 

functions which the PTC system will perform to enhance or preserve safety; 

(4) A document describing the manner in which the PTC system architecture satisfies safety 

requirements; 

(5) A preliminary human factors analysis, including a complete description of all humanmachine interfaces and the impact of interoperability requirements on the same; 

(6) An analysis of the applicability to the PTC system of the requirements of subparts A 

through G of this part that may no longer apply or are satisfied by the PTC system using an 

alternative method, and a complete explanation of the manner in which those requirements are 

otherwise fulfilled; 

(7) A prioritized service restoration and mitigation plan and a description of the necessary 

security measures for the system; 

(8) A description of target safety levels (e.g., MTTHE for major subsystems as defined in 

subpart H of this part), including requirements for system availability and a description of all 

backup methods of operation and any critical assumptions associated with the target levels; 

(9) A complete description of how the PTC system will enforce authorities and signal 

indications; 

(10) A description of the deviation which may be proposed under § 236.1029(c), if 

applicable; and 

(11) A complete description of how the PTC system will appropriately and timely enforce all 

integrated hazard detectors in accordance with § 236.1005(c)(3), if applicable. 

(b) If the Associate Administrator finds that the system described in the PTCDP would 

satisfy the requirements for PTC systems under this subpart and that the applicant has made a 

reasonable showing that a system built to the stated requirements would achieve the level of 

safety mandated for such a system under § 236.1015, the Associate Administrator may grant a 

numbered Type Approval for the system. 

(c) Each Type Approval shall be valid for a period of 5 years, subject to automatic and 

indefinite extension provided that at least one PTC System Certification using the subject PTC 

system has been issued within that period and not revoked. 

(d) The Associate Administrator may prescribe special conditions, amendments, and 

restrictions to any Type Approval as necessary for safety. 

(e) If submitted, an NPI must contain the following information: 

(1) A description of the railroad operation or categories of operations on which the proposed 

PTC system is designed to be used, including train movement density (passenger, freight), 

operating speeds (including a thorough explanation of intended compliance with § 236.1007), 

track characteristics, and railroad operating rules; 

(2) An operational concepts document, including a list with complete descriptions of all 

functions that the proposed PTC system will perform to enhance or preserve safety; 

(3) A description of target safety levels (e.g., MTTHE for major subsystems as defined in 
236-226 

subpart H of this part), including requirements for system availability and a description of all 

backup methods of operation and any critical assumptions associated with the target levels; 

(4) A complete description of how the proposed PTC system will enforce authorities and 

signal indications; and 

(5) A complete description of how the proposed PTC system will appropriately and timely 

enforce all integrated hazard detectors in accordance with § 236.1005(c)(3), if applicable. 

Application: 

This section describes the requirements for a railroad’s PTC system to obtain a Type Approval 

from FRA, and the content requirements for their PTCDP, which shall be filed in accordance 

with § 236.1009 and shall include: a complete description of the PTC system, a description of the 

railroad operation, an operational concepts document, a system architecture document, and 

various other requirements as defined within this section. If the Associate Administrator finds 

that the system described in the PTCDP would satisfy the requirements for PTC systems under 

this subpart and that the applicant has made a reasonable showing that a system built to the stated 

requirements would achieve the level of safety mandated for such a system under § 236.1015, 

the Associate Administrator may grant a numbered Type Approval for the system. 

CLASSIFICATION OF DEFECTS 

§ 236.1013.A1 Failure to submit a PTCDP to FRA by the date stated in the current PTCIP. 

§ 236.1013.A2 Failure to provide the required information in a PTCDP. 

§ 236.1013.D1 Inappropriate use of Type Approval. 

§ 236.1013.D2 Failure to maintain a quality control system. 

§ 236.1013.E1 Failure to develop and/or submit a NPI to FRA in lieu of submitting a PTCDP 

or PTCSP, referencing a Type Approval, or filing a document attesting a Type 

Approval is not necessary. 

§ 236.1013.E2 Failure to provide the required information in an NPI. 

§ 236.1015 PTC Safety Plan content requirements and PTC System Certification. 

(a) Before placing a PTC system required under this part in service, the host railroad must 

submit to FRA a PTCSP and receive a PTC System Certification. If the Associate Administrator 

finds that the PTCSP and supporting documentation support a finding that the system complies 

with this part, the Associate Administrator approves the PTCSP and issues a PTC System 

Certification. Receipt of a PTC System Certification affirms that the PTC system has been 

reviewed and approved by FRA in accordance with, and meets the requirements of, this part. 

(b) A PTCSP submitted under this subpart may reference and utilize in accordance with this 

subpart any Type Approval previously issued by the Associate Administrator to any railroad, 

provided that the railroad: 

(1) Maintains a continually updated PTCPVL pursuant to § 236.1023; and 

(2) Shows that the supplier from which they are procuring the PTC system has established 

and can maintain a quality control system for PTC system design and manufacturing acceptable 
236-227 

to the Associate 

Administrator. The quality control system must include the process for the product supplier or 

vendor to promptly and thoroughly report any safety-relevant failure and previously unidentified 

hazards to each railroad using the product; and 

(3) Provides the applicable licensing information. 

(c) A PTCSP submitted in accordance with this subpart shall: 

(1) Include the FRA approved PTCDP or, if applicable, the FRA issued Type Approval; 

(2)(i) Specifically and rigorously document each variance, including the significance of each 

variance between the PTC system and its applicable operating conditions as described in the 

applicable PTCDP from that as described in the PTCSP, and attest that there are no other such 

variances; or 

(ii) Attest that there are no variances between the PTC system and its applicable operating 

conditions as described in the applicable PTCDP from that as described in the PTCSP; and 

(3) Attest that the system was otherwise built in accordance with the applicable PTCDP and 

PTCSP and achieves the level of safety represented therein. 

(d) A PTCSP shall include the same information required for a PTCDP under § 236.1013(a). 

If a PTCDP has been filed and approved prior to filing of the PTCSP, the PTCSP may 

incorporate the PTCDP by reference, with the exception that a final human factors analysis shall 

be provided. The PTCSP shall contain the following additional elements: 

(1) A hazard log consisting of a comprehensive description of all safety-relevant hazards not 

previously addressed by the vendor or supplier to be addressed during the life-cycle of the PTC 

system, including maximum threshold limits for each hazard (for unidentified hazards, the 

threshold shall be exceeded at one occurrence); 

(2) A description of the safety assurance concepts that are to be used for system 

development, including an explanation of the design principles and assumptions; 

(3) A risk assessment of the as-built PTC system described; 

(4) A hazard mitigation analysis, including a complete and comprehensive description of 

each hazard and the mitigation techniques used; 

(5) A complete description of the safety assessment and Verification and Validation 

processes applied to the PTC system, their results, and whether these processes address the safety 

principles described in Appendix C to this part directly, using other safety criteria, or not at all; 

(6) A complete description of the railroad’s training plan for railroad and contractor 

employees and supervisors necessary to ensure safe and proper installation, implementation, 

operation, maintenance, repair, inspection, testing, and modification of the PTC system; 

(7) A complete description of the specific procedures and test equipment necessary to ensure 

the safe and proper installation, implementation, operation, maintenance, repair, inspection, 

testing, and modification of the PTC system on the railroad and establish safety-critical hazards 

are appropriately mitigated. These procedures, including calibration requirements, shall be 

consistent with or explain deviations from the equipment manufacturer’s recommendations; 

(8) A complete description of any additional warning to be placed in the Operations and 

Maintenance Manual in the same manner specified in § 236.919 and all warning labels to be 

placed on equipment as necessary to ensure safety; 

(9) A complete description of the configuration or revision control measures designed to 

ensure that the railroad or its contractor does not adversely affect the safety-functional 

requirements and that safety-critical hazard mitigation processes are not compromised as a result 

of any such change; 

(10) A complete description of all initial implementation testing procedures necessary to 

establish that safety-functional requirements are met and safety-critical hazards are appropriately 

mitigated; 
236-228 

(11) A complete description of all post-implementation testing (validation) and monitoring 

procedures, including the intervals necessary to establish that safety-functional requirements, 

safety-critical hazard mitigation processes, and safety-critical tolerances are not compromised 

over time, through use, or after maintenance (adjustment, repair, or replacement) is performed; 

(12) A complete description of each record necessary to ensure the safety of the system that 

is associated with periodic maintenance, inspections, tests, adjustments, repairs, or replacements, 

and the system’s resulting conditions, including records of component failures resulting in 

safety-relevant hazards (see § 236.1037); 

(13) A safety analysis to determine whether, when the system is in operation, any risk 

remains of an unintended incursion into a roadway work zone due to human error. If the analysis 

reveals any such risk, the PTCDP and PTCSP shall describe how that risk will be mitigated; 

(14) A more detailed description of any alternative arrangements as already provided under § 

236.1005(a)(1)(i). 

(15) A complete description of how the PTC system will enforce authorities and signal 

indications, unless already completely provided for in the PTCDP; 

(16) A description of how the PTCSP complies with § 236.1019(f), if applicable; 

(17) A description of any deviation in operational requirements for en route failures as 

specified under § 236.1029(c), if applicable and unless already completely provided for in the 

PTCDP; 

(18) A complete description of how the PTC system will appropriately and timely enforce all 

integrated hazard detectors in accordance with § 236.1005; 

(19) An emergency and planned maintenance temporary rerouting plan indicating how 

operations on the subject PTC system will take advantage of the benefits provided under § 

236.1005(g) through (k); and 

(20) The documents and information required under § 236.1007 and § 236.1033. 

(e) The following additional requirements apply to: 

(1) Non-vital overlay. A PTC system proposed as an overlay on the existing method of 

operation and not built in accordance with the safety assurance principles set forth in Appendix 

C of this part must, to the satisfaction of the Associate Administrator, be shown to: 

(i) Reliably execute the functions set forth in § 236.1005; 

(ii) Obtain at least 80 percent reduction of the risk associated with accidents preventable by 

the functions set forth in § 236.1005, when all effects of the change associated with the PTC 

system are taken into account. The supporting risk assessment shall evaluate all intended 

changes in railroad operations coincident with the introduction of the new system; and (iii) 

Maintain a level of safety for each subsequent system modification that is equal to or greater than 

the level of safety for the previous PTC systems. 

(2) Vital overlay. A PTC system proposed on a newly constructed track or as an overlay on 

the existing method of operation and built in accordance with the safety assurance principles set 

forth in Appendix C of this part must, to the satisfaction of the Associate Administrator, be 

shown to: 

(i) Reliably execute the functions set forth in § 236.1005; and 

(ii) Have sufficient documentation to demonstrate that the PTC system, as built, fulfills the 

safety assurance principles set forth in Appendix C of this part. The supporting risk assessment 

may be abbreviated as that term is used in subpart H of this part. 

(3) Stand-alone. A PTC system proposed on a newly constructed track, an existing track for 

which no signal system exists, as a replacement for an existing signal or train control system, or 

otherwise to replace or materially modify the existing method of operation, shall: 

(i) Reliably execute the functions required by § 236.1005 and be demonstrated to do so to 

FRA’s satisfaction; and 

(ii) Have a PTCSP establishing, with a high degree of confidence, that the system will not 
236-229 

introduce new hazards that have not been mitigated. The supporting risk assessment shall 

evaluate all intended changes in railroad operations in relation to the introduction of the new 

system and shall examine in detail the direct and indirect effects of all changes in the method of 

operations. 

(4) Mixed systems. If a PTC system combining overlay, stand-alone, vital, or non-vital 

characteristics is proposed, the railroad shall confer with the Associate Administrator regarding 

appropriate structuring of the safety case and analysis. 

(f) When determining whether the PTCSP fulfills the requirements under paragraph (d) of 

this section, the Associate Administrator may consider all available evidence concerning the 

reliability and availability of the proposed system and any and all safety consequences of the 

proposed changes. In any case where the PTCSP lacks adequate data regarding safety impacts of 

the proposed changes, the Associate Administrator may request the necessary data from the 

applicant. If the requested data is not provided, the Associate Administrator may find that 

potential hazards could or will arise. 

(g) If a PTCSP applies to a system designed to replace an existing certified PTC system, the 

PTCSP will be approved provided that the PTCSP establishes with a high degree of confidence 

that the new system will provide a level of safety not less than the level of safety provided by the 

system to be replaced. 

(h) When reviewing the issue of the potential data errors (for example, errors arising from 

data supplied from other business systems needed to execute the braking algorithm, survey data 

needed for location determination, or mandatory directives issued through the computer aided 

dispatching system), the PTCSP must include a careful identification of each of the risks and a 

discussion of each applicable mitigation. In an appropriate case, such as a case in which the 

residual risk after mitigation is substantial or the underlying method of operation will be 

significantly altered, the Associate Administrator may require submission of a quantitative risk 

assessment addressing these potential errors. 

Application:

This section describes the requirements before placing a PTC system required under this part in 

service. The host railroad must submit to FRA a PTCSP and receive a PTC System 

Certification. A PTCSP shall include the same information required for a PTCDP under § 

236.1013(a). If a PTCDP has been filed and approved prior to filing of the PTCSP, the PTCSP 

may incorporate the PTCDP by reference, with the exception that a final human factors analysis 

shall be provided. The PTCSP shall also contain additional elements as defined within this 

section. When determining whether the PTCSP fulfills the requirements of this section, the 

Associate Administrator may consider all available evidence concerning the reliability and 

availability of the proposed system and any and all safety consequences of the proposed changes. 

CLASSIFICATION OF DEFECTS 

§ 236.1015.A1 Failure to submit a PTCSP to FRA by the date stated in the current PTCIP. 

§ 236.1015.A2 Failure to implement PTC system in accordance with the associated PTCSP and 

resultant system certification. 

§ 236.1015.A3 Failure to maintain PTC system in accordance with the associated PTCSP and 

resultant system certification. 
236-230 

§ 236.1015.B1 Use of, and/or reference to, a Type Approval without updating and/or 

maintaining a PTCPVL. 

§ 236.1015.B2 Use of, and/or reference to, a Type Approval without providing information 

pertaining to the PTC system supplier quality control system. 

§ 236.1015.B3 Use of, and/or reference to, a Type Approval without providing applicable 

licensing information. 

§ 236.1015.C1 Failure to include an FRA approved PTCDP or FRA issued Type Approval with 

a PTCSP. 

§ 236.1015.C2 Failure to document each variance between the PTC system and its applicable 

operating conditions as described in the PTCDP from that as described in the 

PTCSP. 

§ 236.1015.C3 Failure to attest to no other variances, after documenting the variances, between 

the PTC system and its applicable operating conditions as described in the 

PTCDP from that as described in the PTCSP. 

§ 236.1015.C4 Failure to attest to no variances between the PTC system and its applicable 

operating conditions as described in the PTCDP from that as described in the 

PTCSP. 

§ 236.1015.D1 Failure to provide a final human factor analysis with a PTCSP incorporating a 

previously FRA approved PTCDP. 

§ 236.1015.D2 Failure to provide the required information in a PTCSP. 

§ 236.1015.D3 Failure to maintain required supporting documentation. 

§ 236.1015.E1 Failure to provide non-vital overlay PTC system documentation demonstrating 

at least an 80-percent reduction of risk associated with PTC preventable 

accidents. 

§ 236.1015.E2 Failure of a non-vital overlay PTC system to provide an 80-percent reduction of 

risk associated with PTC preventable accidents. 

§ 236.1015.E3 Failure of a non-vital overlay PTC system to maintain a level of safety for each 

subsequent system modification that is equal to or greater than the level of 

safety for the previous PTC systems. 

§ 236.1015.E4 Failure to provide vital overlay system documentation demonstrating the PTC 

system, as built, fulfills the safety assurance principles in Appendix C. 

§ 236.1015.E5 Failure of a vital overlay PTC system to fulfill the safety assurance principles in 

Appendix C. 

§ 236.1015.E6 Failure to provide stand-alone PTC system documentation demonstrating the 

system will not introduce new hazards that have not been mitigated. 
236-231 

§ 236.1015.E7 New hazards introduced by a stand-alone PTC system that have not been 

mitigated. 

§ 236.1015.E8 Failure to confer with the FRA Associate Administrator regarding the 

structuring of the safety case and analysis for the proposed implementation of a 

mixed PTC system. 

§ 236.1015.G1 Failure of a PTCSP for a new system, designed to replace an existing system, to 

document a level of safety for the new PTC system that is equal to or greater 

than the level of safety of the previous PTC system. 

§ 236.1017 Independent Third-Party Verification and Validation. 

(a) The PTCSP must be supported by an independent third-party assessment when the 

Associate Administrator concludes that it is necessary based upon the criteria set forth in § 

236.913, with the exception that consideration of the methodology used in the risk assessment (§ 

236.913(g)(2)(vii)) shall apply only to the extent that a comparative risk assessment was 

required. To the extent practicable, FRA makes this determination not later than review of the 

PTCIP and the accompanying PTCDP or PTCSP. If an independent assessment is required, the 

assessment may apply to the entire system or a designated portion of the system. 

(b) If a PTC system is to undergo an independent assessment in accordance with this section, 

the host railroad may submit to the Associate Administrator a written request that FRA confirm 

whether a particular entity would be considered an independent third party pursuant to this 

section. The request should include supporting information identified in paragraph (c) of this 

section. FRA may request further information to make a determination or provide its 

determination in writing. 

(c) As used in this section, “independent third party” means a technically competent entity 

responsible to and compensated by the railroad (or an association on behalf of one or more 

railroads) that is independent of the PTC system supplier and vendor. An entity that is owned or 

controlled by the supplier or vendor, that is under common ownership or control with the 

supplier or vendor, or that is otherwise involved in the development of the PTC system is not 

considered “independent” within the meaning of this section. 

(d) The independent third-party assessment shall, at a minimum, consist of the activities and 

result in the production of documentation meeting the requirements of Appendix F to this part, 

unless excepted by this part or by FRA order or waiver. 

(e) Information provided that has been certified under the auspices of a foreign railroad 

regulatory entity recognized by the Associate Administrator may, at the Associate 

Administrator’s discretion, be accepted as having been independently verified. 

Application:

This rule requires that the PTCSP be supported by an independent third-party assessment when 

the Associate Administrator concludes that it is necessary based upon the criteria set forth in § 

236.913, with the exception that consideration of the methodology used in the risk assessment (§ 

236.913(g)(2)(vii)) shall apply only to the extent that a comparative risk assessment was 

required. If an independent assessment is required, the assessment may apply to the entire 

system or a designated portion of the system. It further lists the railroads rights and 

responsibilities as they pertain to this section. 

CLASSIFICATION OF DEFECTS 
236-232 

§ 236.1017.A1 Failure to conduct independent third-party verification and validation when 

ordered. 

§ 236.1017.A2 PTCSP not supported by an independent third-party assessment based upon the 

criteria set forth in § 236.913. 

§ 236.1017.A3 Mandatory third-party assessment not per minimum requirements contained in 

Appendix F to Part 236. 

§ 236.1017.C1 Required independent third-party assessment not conducted by a technically 

competent entity. 

§ 236.1017.C2 Independent third party is owned or controlled by the supplier or vendor 

involved in the development of the PTC system. 

§ 236.1019 Main line track exceptions. 

(a) Scope and procedure. This section pertains exclusively to exceptions from the rule that 

trackage over which scheduled intercity and commuter passenger service is provided is 

considered main line track requiring installation of a PTC system. One or more intercity or 

commuter passenger railroads, or freight railroads conducting joint passenger and freight 

operation over the same segment of track may file a main line track exclusion addendum 

(“MTEA”) to its PTCIP requesting to designate track as not main line subject to the conditions 

set forth in paragraphs (b) or (c) of this section. No track shall be designated as yard or terminal 

unless it is identified in an MTEA that is part of an FRA approved PTCIP. 

(b) Passenger terminal exception. FRA will consider an exception in the case of trackage 

used exclusively as yard or terminal tracks by or in support of regularly scheduled intercity or 

commuter passenger service where the MTEA describes in detail the physical boundaries of the 

trackage in question, its use and characteristics (including track and signal charts) and all of the 

following apply: 

(1) The maximum authorized speed for all movements is not greater than 20 miles per hour, 

and that maximum is enforced by any available onboard PTC equipment within the confines of 

the yard or terminal; 

(2) Interlocking rules are in effect prohibiting reverse movements other than on signal 

indications without dispatcher permission; and 

(3) Either of the following conditions exists: 

(i) No freight operations are permitted; or 

(ii) Freight operations are permitted but no passengers will be aboard passenger trains within 

the defined limits. 

(c) Limited operations exception. FRA will consider an exception in the case of a track 

segment used 

for limited operations (operating in accordance with § 236.0 of this part) under one of the 

following sets of conditions: 

(1) The trackage is used for limited operations by at least one passenger railroad subject to at 

least one of the following conditions: 

(i) All trains are limited to restricted speed; 

(ii) Temporal separation of passenger and other trains is maintained as provided in paragraph 

(e) of this section; or 

(iii) Passenger service is operated under a risk mitigation plan submitted by all railroads 
236-233 

involved in the joint operation and approved by FRA. The risk mitigation plan must be supported 

by a risk assessment establishing that the proposed mitigations will achieve a level of safety not 

less than the level of safety that would obtain if the operations were conducted under paragraph 

(c)(1) or (c)(2) of this section. 

(2) Passenger service is operated on a segment of track of a freight railroad that is not a Class 

I railroad on which less than 15 million gross tons of freight traffic is transported annually and 

on which one of the following conditions applies: 

(i) If the segment is unsignaled and no more than four regularly scheduled passenger trains 

are operated during a calendar day, or 

(ii) If the segment is signaled (e.g., equipped with a traffic control system, automatic block 

signal system, or cab signal system) and no more than 12 regularly scheduled passenger trains 

are operated during a calendar day. 

(3) Not more than four passenger trains per day are operated on a segment of track of a Class 

I freight railroad on which less than 15 million gross tons of freight traffic is transported 

annually. 

(d) A limited operations exception under paragraph (c) is subject to FRA review and 

approval. FRA may require a collision hazard analysis to identify hazards and may require that 

specific mitigations be undertaken. Operations under any such exception shall be conducted 

subject to the terms and conditions of the approval. Any main line track exclusion is subject to 

periodic review. 

(e) Temporal separation. As used in this section, temporal separation means that limited 

passenger and freight operations do not operate on any segment of shared track during the same 

period and also refers to the processes or physical arrangements, or both, in place to ensure that 

temporal separation is established and maintained at all times. The use of exclusive authorities 

under mandatory directives is not, by itself, sufficient to establish that temporal separation is 

achieved. Procedures to ensure temporal separation shall include verification checks between 

passenger and freight operations and effective physical means to positively ensure segregation of 

passenger and freight operations in accordance with this paragraph. 

(f) PTCSP requirement. No PTCSP—filed after the approval of a PTCIP with an MTEA—

shall be approved by FRA unless it attests that no changes, except for those included in an FRA 

approved RFA, have been made to the information in the PTCIP and MTEA required by 

paragraph (b) or (c) of this section. 

(g) Designation modifications. If subsequent to approval of its PTCIP or PTCSP the railroad 

seeks to modify which track or tracks should be designated as main line or not main line, it shall 

request modification of its PTCIP or PTCSP, as applicable, in accordance with § 236.1021. 

Application:

This rule identifies the conditions under which a railroad may request relief from installing a 

PTC system on a required line. They include passenger terminal exceptions, limited operations 

exceptions, and temporal separation. Each of these conditions has specific guidelines which 

must be met as defined within this section. 

CLASSIFICATION OF DEFECTS 

§ 236.1019.A1 Track designated as yard or terminal is not identified in a MTEA that is part of 

an FRA approved PTCIP. 

§ 236.1019.B1 Revenue operations conducted in noncompliance with the Passenger Terminal 

Exception. 
236-234 

§ 236.1019.B2 Physical boundaries of trackage used exclusively as yard or terminal not 

described in detail in an approved PTCIP. 

§ 236.1019.B3 Use and characteristics of trackage used exclusively as yard or terminal not 

described in detail in an approved PTCIP. 

§ 236.1019.B4 Maximum authorized speed for any movement exceeds 20 mph for tracks 

identified in MTEA Passenger Terminal Exception as yard or terminal. 

§ 236.1019.B5 Maximum authorized speed is not enforced by any available onboard PTC 

equipment for tracks identified in MTEA Passenger Terminal Exception as yard 

or terminal. 

§ 236.1019.B6 Tracks identified in a MTEA for Passenger Terminal Exception do not have 

interlocking rules in effect prohibiting reverse movements other than on signal 

indication without dispatcher permission. 

§ 236.1019.B7 Tracks identified in a MTEA for Passenger Terminal Exception has freight 

operation and permit passengers aboard passenger trains within the defined 

limits. 

§ 236.1019.C1 Revenue operations conducted in noncompliance with the Limited Operations 

Exception. 

§ 236.1019.C2 Trackage used for limited operations trains not limited to restricted speed, 

temporal separation, or under an approved risk mitigation plan submitted by all 

railroads involved. 

§ 236.1019.C3 Passenger service operated under the Limited Operations Exception on a Class 1 

railroad segment of track on which more than 15 million gross tons of freight 

traffic is transported annually. 

§ 236.1019.C4 More than four regularly scheduled passenger trains are operated under the 

Limited Operations Exception during a calendar day on a nonsignaled segment 

of track. 

§ 236.1019.C5 More than 12 regularly scheduled passenger trains are operated under the 

Limited Operations Exception during a calendar day on a signaled segment of 

track. 

§ 236.1019.C6 More than four passenger trains per day are operated under the Limited 

Operations Exception on a Class 1 railroad segment of track on which less than 

15 million gross tons of freight traffic is transported annually. 

§ 236.1019.D1 Limited operations not conducted subject to terms and conditions of an 

approved Limited Operations Exception. 

§ 236.1019.E1 Passenger and freight operations permitted during the same period on a segment 

of track operating under a Temporal Separation Exception. 
236-235 

§ 236.1019.E2 Exclusive authorities under mandatory directives used as only method to 

establish temporal separation. 

§ 236.1019.E3 Verification checks between passenger and freight operations not used to ensure 

temporal separation of trains. 

§ 236.1019.E4 Effective physical means to positively ensure segregation of passenger and 

freight operations not available. 

§ 236.1019.G1 Designation of tracks as main line or not main line modified without request for 

modification of the PTCIP or PTCSP in accordance with § 236.1021. 

§ 236.1020 Exclusion of track segments for implementation due to cessation of PIH 

materials service or rerouting. 

(a) Purpose and scope. This section sets forth the conditions under which track segments 

identified in the 2008 baseline described in § 236.1005(b)(2) may be removed from the PTCIP. 

A track segment qualified for removal under this section may be removed after FRA approves a 

request contained in the PTCIP or an RFA filed prior to the required and scheduled PTC 

installation date for the subject track segment. 

(b) Cessation of PIH materials service. Except as provided in paragraph (c) of this section, 

the following three conditions must all be satisfied in order to justify removal of a track segment 

from the PTCIP: 

(1) Local service. The railroad must affirm that there is no remaining local PIH materials 

traffic expected on the track segment, or that service is expected to cease as of a date certain 

prior to December 31, 2015. In the case of future cessation of local service, the expectation may 

be documented by statements from all current PIH materials shippers and/or consignees. The 

railroad is not required to anticipate future requests for service not in keeping with prior service 

patterns. (See § 236.1005(b)(3)). 

(2) Overhead traffic. (i) To the extent that the track segment carried PIH materials traffic 

other than local traffic in 2008, the railroad must establish that current or prospective rerouting to 

one or more alternate track segments is justified. In making this showing, the railroad must 

assume, for purposes of analysis only, that both the subject track segment and the alternative 

route(s) will be equipped and operated with PTC. Rerouting will be justified if the analysis is 

conducted in accordance with the same procedures and using the same methodology as required 

for safety and security route analysis under 49 CFR 172.820, with appropriate quantitative 

weight given to risk reduction effected by installation of a PTC system. If the track segment in 

question is not clearly the route posing the least overall safety and security risks, then removal of 

the line from the PTCIP may be granted. 

(ii) However, unlike analysis under part 172, FRA will consider the case for rerouting and 

removal of the line from the PTCIP to be made if the alternative(s) to the track segment sought to 

be removed has substantially the same overall safety and security risks as the subject routes 

under the stipulated conditions for analysis. In determining whether risk is substantially the 

same, FRA will consider the volume of traffic diverted, and such other factors as safety may 

require. 

(3) Residual risk. In the case of a track segment for which cessation of local service is 

established under paragraph (b)(1) of this section and for which analysis shows any overhead 

PIH materials traffic could properly be rerouted under paragraph (b)(2) of this section, the 

railroad shall also establish that the remaining risk arising from rail operations on the track 
236-236 

segment— pertaining to events that can be prevented or mitigated in severity by a PTC system—

is less than the average equivalent risk per route mile on track segments required to be equipped 

with PTC because of annual gross tonnage and the presence of PIH materials traffic (excluding 

track segments also carrying passenger traffic). Such average equivalent risk shall be determined 

as of a time prior to installation of PTC on the line segments. This provision of the rule requires 

a future rulemaking to finalize and implement a risk evaluation methodology. Lines identified 

for removal subject to this provision will not be required to be equipped with PTC prior to the 

issuance of a final rule detailing the methodology. 

(i) FRA will develop a risk evaluation methodology for the purpose of conducting the 

analysis required pursuant to paragraph (b)(3) of this section. The risk evaluation methodology 

will be finalized through a separate rulemaking proceeding that will permit all interested parties 

to provide input on the specific methodology and, whether that methodology should be 

employed. If in the rulemaking proceeding FRA determines that a risk methodology should not 

be employed, then FRA will amend this final rule to eliminate the residual risk provisions. 

(ii) Any track segment qualifying for consideration under paragraph (b)(3) of this section and 

identified by the railroad for requested removal from the PTCIP shall be considered to be 

‘‘pending for decision’’ until such time as FRA has published the risk evaluation methodology 

identified in paragraph (b)(3)(i) of this section. If a final risk evaluation methodology is 

employed, the railroad may be requested to provide supplemental information related to its 

request for removal of specific lines. The railroad is not required to commence installation of 

PTC on any track segment ‘‘pending for decision’’ under this paragraph, until a final FRA 

determination is made. 

(c) If a track segment qualifies for removal from the PTCIP under paragraphs (b)(1) and 

(b)(2) of this section but does not meet the test of paragraph (b)(3) of this section, the railroad 

may nevertheless request that the PTCIP be amended to remove the track segment based upon 

compensating reductions in the risk 

related to PTC preventable accidents based on installation of PTC technology on one or more 

track segments not otherwise required to be equipped. Upon a proper showing that the increment 

of risk reduction is at least as great on the substitute line as it would be on the line sought to be 

excluded from the PTCIP, FRA may approve the substitution. 

Application:

This section sets forth the conditions under which track segments identified in the 2008 baseline 

described in § 236.1005(b)(2) may be removed from the PTCIP. It defines the requirements that 

a railroad must meet to be approved for the exception of installing a PTC system. 

CLASSIFICATION OF DEFECTS 

§ 236.1020.A1 Removal of a track segment from a PTCIP without FRA approval. 

§ 236.1020.B1 Failure to affirm there is no remaining local PIH traffic, or PIH traffic will cease 

by December 31, 2015, on a track segment requested to be removed from a 

PTCIP. 

§ 236.1020.B2 Failure to provide documentation from shippers and/or consignees attesting to 

cessation of current PIH traffic by December 31, 2015. 

§ 236.1020.B3 Failure to provide significant justification for the rerouting of overhead PIH 
236-237 

traffic to one or more alternate track segments. 

§ 236.1020.B4 Failure to show residual risk of remaining rail operations on a track segment 

requested to be removed from a PTCIP is less than average equivalent risk on 

track segments required to PTC equipped. 

§ 236.1020.B5 Failure to provide additional requested information for track segments requested 

to be removed from a PTCIP. 

§ 236.1020.C1 Failure to provide significant documentation in support of implementing PTC 

on a substitute track segment in lieu of one listed in a PTCIP. 

§ 236.1021 Discontinuances, material modifications, and amendments. 

(a) No changes, as defined by this section, to a PTC system, PTCIP, PTCDP, or PTCSP, shall 

be made unless: 

(1) The railroad files a request for amendment (“RFA”) to the applicable PTCIP, PTCDP, or 

PTCSP with the Associate Administrator; and 

(2) The Associate Administrator approves the RFA. 

(b) After approval of an RFA in accordance with paragraph (a) of this section, the railroad 

shall immediately adopt and comply with the amendment. 

(c) In lieu of a separate filing under part 235 of this chapter, a railroad may request approval 

of a discontinuance or material modification of a signal or train control system by filing an RFA 

to its PTCIP, PTCDP, or PTCSP with the Associate Administrator. 

(d) An RFA made in accordance with this section will not be approved by FRA unless the 

request includes: 

(1) The information listed in § 235.10 of this chapter and the railroad provides FRA upon 

request any additional information necessary to evaluate the RFA (see § 235.12), including: 

(2) The proposed modifications; 

(3) The reasons for each modification; 

(4) The changes to the PTCIP, PTCDP, or PTCSP, as applicable; 

(5) Each modification’s effect on PTC system safety; 

(6) An approximate timetable for filing of the PTCDP, PTCSP, or both, if the amendment 

pertains to a PTCIP; and 

(7) An explanation of whether each change to the PTCSP is planned or unplanned. 

(i) Unplanned changes that affect the Type Approval’s PTCDP require submission and 

approval in accordance with § 236.1013 of a new PTCDP, followed by submission and approval 

in accordance with § 236.1015 of a new PTCSP for the PTC system. 

(ii) Unplanned changes that do not affect the Type Approval’s PTCDP require submission 

and approval of a new PTCSP. 

(iii) Unplanned changes are changes affecting system safety that have not been documented 

in the PTCSP. The impact of unplanned changes on PTC system safety has not yet been 

determined. 

(iv) Planned changes may be implemented after they have undergone suitable regression 

testing to demonstrate, to the satisfaction of the Associate Administrator, they have been 

correctly implemented and their implementation does not degrade safety. 

(v) Planned changes are changes affecting system safety in the PTCSP and have been 

included in all required analysis under § 236.1015. The impact of these changes on the PTC 
236-238 

system’s safety has been incorporated as an integral part of the approved PTCSP safety analysis. 

(e) If the RFA includes a request for approval of a discontinuance or material modification of 

a signal or train control system, FRA will publish a notice in the Federal Register of the 

application and will invite public comment in accordance with part 211 of this chapter. 

(f) When considering the RFA, FRA will review the issue of the discontinuance or material 

modification and determine whether granting the request is in the public interest and consistent 

with railroad safety, taking into consideration all changes in the method of operation and system 

functionalities, both within normal PTC system availability and in the case of a system failed 

state (unavailable), contemplated in conjunction with installation of the PTC system. The 

railroad submitting the RFA must, at FRA’s request, perform field testing in accordance with § 

236.1035 or engage in Verification and Validation in accordance with § 236.1017. 

(g) FRA may issue at its discretion a new Type Approval number for a PTC system modified 

under this section. 

(h) Changes requiring filing of an RFA. Except as provided by paragraph (i), an RFA shall 

be filed to request the following: 

(1) Discontinuance of a PTC system, or other similar appliance or device; 

(2) Decrease of the PTC system’s limits (e.g., exclusion or removal of a PTC system on a 

track segment); 

(3) Modification of a safety critical element of a PTC system; or 

(4) Modification of a PTC system that affects the safety critical functionality of any other 

PTC system with which it interoperates. 

(i) Discontinuances not requiring the filing of an RFA. It is not necessary to file an RFA for 

the following discontinuances: 

(1) Removal of a PTC system from track approved for abandonment by formal proceeding; 

(2) Removal of PTC devices used to provide protection against unusual contingencies such 

as landslide, burned bridge, high water, high and wide load, or tunnel protection when the 

unusual contingency no longer exists; 

(3) Removal of the PTC devices that are used on a movable bridge that has been permanently 

closed by the formal approval of another government agency and is mechanically secured in the 

closed position for rail traffic; or 

(4) Removal of the PTC system from service for a period not to exceed 6 months that is 

necessitated by catastrophic occurrence such as derailment, flood, fire, or hurricane, or 

earthquake. 

(j) Changes not requiring the filing of an RFA. When the resultant change to the PTC system 

will comply with an approved PTCSP of this part, it is not necessary to file for approval to 

decrease the limits of a system when it involves the: 

(1) Decrease of the limits of a PTC system when interlocked switches, derails, or movablepoint frogs are not involved; 

(2) Removal of an electric or mechanical lock, or signal used in lieu thereof, from handoperated switch in a PTC system where train speed over such switch does not exceed 20 miles 

per hour, and use of those devices has not been part of the considerations for approval of a 

PTCSP; or 

(3) Removal of an electric or mechanical lock, or signal used in lieu thereof, from a handoperated switch in a PTC system where trains are not permitted to clear the main track at such 

switch and use of those devices has not been a part of the considerations for approval of a 

PTCSP. 

(k) Modifications not requiring the filing of an RFA. When the resultant arrangement will 

comply with an approved PTCSP of this part, it is not necessary to file an application for 

approval of the following modifications: 
236-239 

(1) A modification that is required to comply with an order of the Federal Railroad 

Administration or any section of part 236 of this title; 

(2) Installation of devices used to provide protection against unusual contingencies such as 

landslide, burned bridges, high water, high and wide loads, or dragging equipment; 

(3) Elimination of existing track other than a second main track; 

(4) Extension or shortening of a passing siding; or 

(5) The temporary or permanent arrangement of existing systems necessitated by highwayrail grade separation construction. Temporary arrangements shall be removed within six months 

following completion of construction. 

Application:

This section describes the procedures and circumstances in which a railroad can request 

discontinuances, material modifications, and amendments. A railroad must file a Request for 

Amendment (RFA) unless otherwise defined within this section. There is specific information 

required within the RFA which must be present and specific criteria which must be met before 

approval can be granted. 

CLASSIFICATION OF DEFECTS 

§ 236.1021.A1 Changes made to a PTC system, PTCIP, PTCDP, or PTCSP without first filing 

an RFA. 

§ 236.1021.A2 Changes made to a PTC system, PTCIP, PTCDP, or PTCSP without approval of 

an RFA. 

§ 236.1021.B1 Failure to immediately adopt and comply with approved RFA for an amendment 

to a PTC System, PTCIP, PTCDP, or PTCSP. 

§ 236.1021.C1 Failure to request approval of a discontinuance or material modification of a 

signal or train control system by filing an RFA in lieu of a separate filing under 

Part 235. 

§ 236.1021.D1 Information listed in § 235.10 not included in an RFA for a material 

modification or discontinuance of a signal or train control system. 

§ 236.1021.D2 Failure to provide other information requested for evaluation of an RFA. 

§ 236.1021.D3 Failure to submit a new PTCDP and/or PTCSP for approval when unplanned 

changes affect the original Type Approval’s PTCDP. 

§ 236.1021.D4 Failure to submit a new PTCSP for approval due to unplanned changes affecting 

PTC system safety. 

§ 236.1021.D5 Planned changes implemented prior to suitable regression testing. 

§ 236.1021.D6 Planned changes incorrectly implemented. 

§ 236.1021.D7 Implementation of planned changes degrades safety. 
236-240 

§ 236.1021.F1 Failure to perform requested field testing of an approved RFA. 

§ 236.1021.H1 Discontinuance or material modification of a PTC system without approval 

when required. 

§ 236.1021.H2 RFA not filed for the discontinuance of a PTC system, or other similar 

appliance or device. 

§ 236.1021.H3 RFA not filed for approval of decreasing a PTC system’s limits. 

§ 236.1021.H4 RFA not filed for approval of modification to a safety-critical element of a PTC 

system. 

§ 236.1021.H5 RFA not filed for approval of modification to a PTC system that affects the 

safety-critical functionality of any other PTC system with which it interoperates. 

§ 236.1023 Errors and Malfunctions. 

(a) Each railroad implementing a PTC system on its property shall establish and continually 

update a PTC Product Vendor List (PTCPVL) that includes all vendors and suppliers of each 

PTC system, subsystem, component, and associated product, and process in use system wide. 

The PTCPVL shall be made available to FRA upon request. 

(b)(1) The railroad shall specify within its PTCSP all contractual arrangements with 

hardware and software suppliers or vendors for immediate notification between the parties of any 

and all safety-critical software failures, upgrades, patches, or revisions, as well as any hardware 

repairs, replacements, or modifications for their PTC system, subsystems, or components. 

(2) A vendor or supplier, on receipt of a report of any safety-critical failure to their product, 

shall promptly notify all other railroads that are using that product, whether or not the other 

railroads have experienced the reported failure of that safety-critical system, subsystem, or 

component. 

(3) The notification from a supplier to any railroad shall include explanation from the 

supplier of the reasons for such notification, the circumstances associated with the failure, and 

any recommended mitigation actions to be taken pending determination of the root cause and 

final corrective actions. 

(c) The railroad shall: 

(1) Specify the railroad’s process and procedures in its PTCSP for action upon their receipt 

of notification of safety-critical failure, as well as receipt of a safety-critical upgrade, patch, 

revision, repair, replacement, or modification. 

(2) Identify configuration/revision control measures in its PTCSP that are designed to ensure 

the safety-functional requirements and the safety-critical hazard mitigation processes are not 

compromised as a result of any change and that such a change can be audited. 

(d) The railroad shall provide to the applicable vendor or supplier the railroad’s procedures 

for action upon notification of a safety-critical failure, upgrade, patch, or revision for the PTC 

system, subsystem, component, product, or process, and actions to be taken until the faulty 

system, subsystem, or component has been adjusted, repaired or replaced. 

(e) After the product is placed in service, the railroad shall maintain a database of all safety-
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relevant hazards as set forth in the PTCSP and those that had not previously been identified in 

the PTCSP. If the frequency of the safety-relevant hazard exceeds the thresholds set forth in the 

PTCSP, or has not been previously identified in the appropriate risk analysis, the railroad shall: 

(1) Notify the applicable vendor or supplier and FRA of the failure, malfunction, or defective 

condition that decreased or eliminated the safety functionality; 

(2) Keep the applicable vendor or supplier and FRA apprised on a continual basis of the 

status of any and all subsequent failures; and 

(3) Take prompt counter measures to reduce or eliminate the frequency of the safety relevant 

hazards below the threshold identified in the PTCSP. 

(f) Each notification to FRA required by this section shall: 

(1) Be made within 15 days after the vendor, supplier, or railroad discovers the failure, 

malfunction, or defective condition. However, a report that is due on a Saturday or a Sunday 

may be delivered on the following Monday and one that is due on a holiday may be delivered on 

the next business day; 

(2) Be transmitted in a manner and form acceptable to the Associate Administrator and by 

the most expeditious method available; and 

(3) Include as much available and applicable information as possible, including: 

(i) PTC system name and model; 

(ii) Identification of the part, component, or system involved, including the part number as 

applicable; 

(iii) Nature of the failure, malfunctions, or defective condition; 

(iv) Mitigation taken to ensure the safety of train operation, railroad employees, and the 

public; and 

(v) The estimated time to correct the failure. 

(4) In the event that all information required by paragraph (f)(3) of this section is not 

immediately available, the non-available information shall be forwarded to the Associate 

Administrator as soon as practicable in supplemental reports. 

(g) Whenever any investigation of an accident or service difficulty report shows that a PTC 

system or product is unsafe because of a manufacturing or design defect, the railroad and its 

vendor or supplier shall, upon request of the Associate Administrator, report to the Associate 

Administrator the results of its investigation and any action taken or proposed to correct that 

defect. 

(h) PTC system and product suppliers and vendors shall: 

(1) Promptly report any safety-relevant failures or defective conditions, previously 

unidentified hazards, and recommended mitigation actions in their PTC system, subsystem, or 

component to each railroad using the product; and 

(2) Notify FRA of any safety-relevant failure, defective condition, or previously unidentified 

hazard discovered by the vendor or supplier and the identity of each affected and notified 

railroad. 

(i) The requirements of this section do not apply to failures, malfunctions, or defective 

conditions that: 

(1) Are caused by improper maintenance or improper usage; or 

(2) Have been previously identified to the FRA, vendor or supplier, and applicable user 

railroads. 

(j) When any safety-critical PTC system, subsystem, or component fails to perform its 

intended function, the cause shall be determined and the faulty product adjusted, repaired, or 

replaced without undue delay. Until corrective action is completed, a railroad shall take 

appropriate action to ensure safety and reliability as specified within its PTCSP. 

(k) Any railroad experiencing a failure of a system resulting in a more favorable aspect than 

intended or other condition hazardous to the movement of a train shall comply with the reporting 
236-242 

requirements, including the making of a telephonic report of an accident or incident involving 

such failure, under part 233 of this chapter. Filing of one or more reports under part 233 of this 

chapter does not exempt a railroad, vendor, or supplier from the reporting requirements 

contained in this section. 

Application:

The requirements of this section provide the process and procedures for tracking, reporting, and 

correction of errors and malfunctions. Included in this section are the procedures for the 

railroads responsibilities to maintain and make available to the FRA a PTCPVL along with the 

procedures for reporting a safety-critical incident. 

CLASSIFICATION OF DEFECTS 

§ 236.1023.A1 PTCPVL not established. 

 

§ 236.1023.A2 Failure to maintain PTCPVL. 

§ 236.1023.A3 PTCPVL not available to FRA upon request. 

§ 236.1023.B1 Contractual arrangements with hardware suppliers, software suppliers, and/or 

vendors not specified in the PTCSP. 

§ 236.1023.B2 Failure of a supplier to promptly provide proper notification of identified PTC 

system safety-critical failure to all railroads using that product. 

§ 236.1023.B3 Notification of a safety-critical failure does not include reasons for such 

notification, circumstances associated with the failure, and/or recommended 

mitigation actions. 

 

§ 236.1023.C1 Failure to provide processes and procedures in the PTCSP for actions upon 

notification of safety-critical failures, safety-critical upgrades, patch revisions, 

repair, replacement, or modification. 

§ 236.1023.C2 Failure to identify configuration/revision control measures in the PTCSP. 

§ 236.1023.D1 Failure to provide vendor and/or supplier the railroad procedures for action 

upon notification of a safety-critical failure, upgrade, patch, or revision of PTC 

system, subsystem, component, product, or process. 

§ 236.1023.D2 Failure to provide vendor and/or supplier the railroad procedures for action to 

be taken until faulty PTC system, subsystem, or component has been adjusted, 

repaired, or replaced. 

§ 236.1023.E1 Failure to maintain a database of all safety-relevant hazards of a PTC system in 

service. 

§ 236.1023.E2 Failure to notify FRA, vendor, and/or supplier if the frequency of a safetyrelevant hazard exceeds the threshold set forth in the PTCSP. 
236-243 

§ 236.1023.E3 Failure to notify FRA, vendor, and/or supplier of a safety-relevant hazard not 

previously identified. 

§ 236.1023.E4 Failure to update FRA, the vendor, and/or supplier of any and all subsequent 

failures related to a safety-relevant hazardous event. 

§ 236.1023.E5 Failure to take counter measures to reduce or eliminate the frequency of any 

safety-relevant hazard above the threshold identified in the PTCSP. 

§ 236.1023.F1 Failure to provide notification to FRA of a failure, malfunction, or defective 

condition within 15 business days. 

§ 236.1023.F2 Notification to FRA of a failure, malfunction, or defective condition not 

transmitted expeditiously. 

§ 236.1023.F3 Notification to FRA of a failure, malfunction, or defective condition not 

transmitted in an acceptable manner and form. 

§ 236.1023.F4 Failure to provide FRA all available and applicable required information when 

reporting failure, malfunction, or defective condition. 

§ 236.1023.F5 Failure to provide FRA supplemental reports as required information of the 

failure, malfunction, or defective condition becomes available. 

§ 236.1023.G1 Failure to respond to an FRA request to report results of an investigation of an 

accident or service difficulty revealing a PTC system or product is unsafe 

because of a manufacturing or design defect. 

§ 236.1023.G2 Failure to respond to an FRA request to report any action taken or proposed as 

the result of an investigation of an accident or service difficulty revealing a PTC 

system or product is unsafe. 

§ 236.1023.H1 Failure of a PTC supplier and/or vendor to promptly report to each affected 

railroad any safety-relevant failures or defective conditions, previously 

unidentified hazards, and/or recommended mitigation actions of a PTC system, 

subsystem, or component. 

§ 236.1023.H2 Failure of a PTC supplier and/or vendor to notify FRA of any safety-relevant 

failure, defective condition, or previously unidentified hazard. 

§ 236.1023.H3 Notification to FRA of any safety-relevant failure, defective condition, or 

previously unidentified hazard does not include the identity of each affected and 

notified railroad. 

§ 236.1023.J1 Safety-critical PTC system, subsystem, and/or component, essential to the 

safety of train operation, failing to perform its intended function not adjusted 

without undue delay. 
236-244 

§ 236.1023.J2 Safety-critical PTC system, subsystem, and/or component, essential to the 

safety of train operation, failing to perform its intended function not repaired 

without undue delay. 

§ 236.1023.J3 Safety-critical PTC system, subsystem, and/or component, essential to the 

safety of train operation, failing to perform its intended function not replaced 

without undue delay. 

§ 236.1023.J4 Cause not determined for any safety-critical PTC system, subsystem, and/or 

component out of correspondence with known operating conditions. 

§ 236.1023.J5 Failure to take appropriate action prior to completion of corrective action, as 

specified within the carrier’s PTCSP, to ensure safety and reliability when any 

safety-critical PTC system, subsystem or component fails to perform its 

intended function. 

§ 236.1023.K1 Report not made of the failure of a system resulting in a more favorable aspect 

than intended or other condition hazardous to the movement of a train, per Part 

233. 

§ 236.1025 [RESERVED] 

§236.1027 PTC system exclusions. 

(a) The requirements of this subpart apply to each office automation system that performs 

safety-critical functions within, or affects the safety performance of, the PTC system. For 

purposes of this section, “office automation system” means any centralized or distributed 

computer-based system that directly or indirectly controls the active movement of trains in a rail 

network. 

(b) Changes or modifications to PTC systems otherwise excluded from the requirements of 

this subpart by this section do not exclude those PTC systems from the requirements of this 

subpart if the changes or modifications result in a degradation of safety or a material decrease in 

safety-critical functionality. 

(c) Primary train control systems cannot be integrated with locomotive electronic systems 

unless the complete integrated systems: 

(1) Have been shown to be designed on fail-safe principles; 

(2) Have demonstrated to operate in a fail-safe mode; 

(3) Have a manual fail-safe fallback and override to allow the locomotive to be brought to a 

safe stop in the event of any loss of electronic control; and 

(4) Are included in the approved and applicable PTCDP and PTCSP. 

(d) PTC systems excluded by this section from the requirements of this subpart remain 

subject to subparts A through H of this part as applicable. 

Application:

The requirements of this subpart apply to each office automation system that performs safetycritical functions within, or affects the safety performance of, the PTC system. For purposes of 

this section “office automation system” means any centralized or distributed computer-based 

system that directly or indirectly controls the active movement of trains in a rail network. 
236-245 

PTC systems excluded by this section from the requirements of this subpart remain subject to 

Subparts A through H of this part as applicable. 

CLASSIFICATION OF DEFECTS 

§ 236.1027.B1 PTC office automated system changes or modification resulted in a degradation 

of safety or a material decrease in safety-critical functionality. 

§ 236.1027.C1 Integration of primary train control system with locomotive not designed on 

fail-safe principle. 

§ 236.1027.C2 Integration of primary train control system with locomotive electronic system 

without demonstration of operation in a fail-safe mode. 

§ 236.1027.C3 Primary train control system integrated with locomotive failed to operate in a 

fail-safe mode. 

§ 236.1027.C4 Primary train control system integrated with a locomotive electronic system 

does not have a manual fail-safe fallback and override to allow the locomotive 

to be brought to a safe stop in the event of any loss of electronic control. 

§ 236.1027.C5 Primary train control system integrated with a locomotive electronic system is 

not included in an approved and applicable PTCDP and PTCSP. 

§ 236.1029 PTC system use and en route failures. 

(a) When any safety-critical PTC system component fails to perform its intended function, 

the cause must be determined and the faulty component adjusted, repaired, or replaced without 

undue delay. Until repair of such essential components are completed, a railroad shall take 

appropriate action as specified in its PTCSP. 

(b) Where a PTC onboard apparatus on a controlling locomotive that is operating in or is to 

be operated within a PTC system fails or is otherwise cut-out while en route (i.e, after the train 

has departed its initial terminal), the train may only continue in accordance with the following: 

(1) The train may proceed at restricted speed, or if a block signal system is in operation 

according to signal indication at medium speed, to the next available point where communication 

of a report can be made to a designated railroad officer of the host railroad; 

(2) Upon completion and communication of the report required in paragraph (b)(1) of this 

section, or where immediate electronic report of said condition is appropriately provided by the 

PTC system itself, a train may continue to a point where an absolute block can be established in 

advance of the train in accordance with the following: 

(i) Where no block signal system is in use, the train may proceed at restricted speed, or 

(ii) Where a block signal system is in operation according to signal indication, the train may 

proceed at a speed not to exceed medium speed. 

(3) Upon reaching the location where an absolute block has been established in advance of 

the train, as referenced in paragraph (b)(2) of this section, the train may proceed in accordance 

with the following: 

(i) Where no block signal system is in use, the train may proceed at medium speed; however, 

if the involved train is a passenger train or a train hauling any amount of PIH material, it may 

only proceed at a speed not to exceed 30 miles per hour. 

(ii) Where a block signal system is in use, a passenger train may proceed at a speed not to 
236-246 

exceed 59 miles per hour and a freight train may proceed at a speed not to exceed 49 miles per 

hour. 

(iii) Except as provided in paragraph (c), where a cab signal system with an automatic train 

control system is in operation, the train may proceed at a speed not to exceed 79 miles per hour. 

(c) In order for a train equipped with PTC traversing a track segment equipped with PTC to 

deviate from the operating limitations contained in paragraph (b) of this section, the deviation 

must be described and justified in the FRA approved PTCDP or PTCSP, or the Order of 

Particular Applicability, as applicable. 

(d) Each railroad shall comply with all provisions in the applicable PTCDP and PTCSP for 

each PTC system it uses and shall operate within the scope of initial operational assumptions and 

predefined changes identified. 

(e) The normal functioning of any safety-critical PTC system must not be interfered with in 

testing or otherwise without first taking measures to provide for the safe movement of trains, 

locomotives, roadway workers, and on-track equipment that depend on the normal functioning of 

the system. 

(f) The PTC system’s onboard apparatus shall be so arranged that each member of the crew 

assigned to perform duties in the locomotive can receive the same PTC information displayed in 

the same manner and execute any functions necessary to that crew member’s duties. The 

locomotive engineer shall not be required to perform functions related to the PTC system while 

the train is moving that have the potential to distract the locomotive engineer from performance 

of other safety-critical duties. 

Application:

This section defines the responsibilities and procedures that a railroad must take when an en 

route PTC failure occurs. Depending on the underlying signal system in place, it also describes 

the maximum permissible speed for a train in the event of an equipment failure. It also describes 

the placement of the onboard apparatus. 

CLASSIFICATION OF DEFECTS 

§ 236.1029.A1 Cause not determined without undue delay for safety-critical PTC system 

component failing to perform its intended function. 

§ 236.1029.A2 PTC system component, essential to the safety of train operation, failing to 

perform its intended function not adjusted without undue delay. 

§ 236.1029.A3 PTC system component, essential to the safety of train operation, failing to 

perform its intended function not repaired without undue delay. 

§ 236.1029.A4 PTC system component, essential to the safety of train operation, failing to 

perform its intended function not replaced without undue delay. 

§ 236.1029.A5 Failure to take appropriate action prior to completion of corrective action, as 

specified within the carrier’s PTCSP, to ensure safety and reliability when any 

essential PTC component fails to perform its intended function. 
236-247 

§ 236.1029.B1 Train initially permitted to proceed at greater than restricted speed in nonsignaled territory when PTC device fails and/or is cut out en route. 

§ 236.1029.B2 Train initially permitted to proceed at greater than medium speed in signaled 

territory when PTC device fails and/or is cut out en route. 

§ 236.1029.B3 Report not made to designated officer at the next available point of 

communication after PTC device fails and/or is cut out en route. 

§ 236.1029.B4 Train permitted to proceed at greater than medium speed within an absolute 

block in non-signaled territory when PTC device fails and/or is cut out en route. 

§ 236.1029.B5 PIH train permitted to proceed at greater than 30 mph within an absolute block 

in non-signaled territory when PTC device fails and/or is cut out en route. 

§ 236.1029.B6 Freight train permitted to proceed at greater than 49 mph within an absolute 

block in signaled territory when PTC device fails and/or is cut out en route. 

§ 236.1029.B7 Passenger train permitted to proceed at greater than 59 mph within an absolute 

block in signaled territory when PTC device fails and/or is cut out en route. 

§ 236.1029.B8 Train permitted to proceed at greater than 79 mph within an absolute block in 

ATC territory when PTC device fails and/or is cut out en route. 

§ 236.1029.C1 Train permitted to deviate from operational limitations when PTC device fails 

and/or is cut out en route without such deviation described and justified in an 

FRA approved PTCDP, PTCSP, and/or the Order of Particular Applicability. 

§ 236.1029.D1 Railroad operations not within the scope of initial operational assumptions and 

predefined changes identified in applicable PTCDP and PTCSP for each PTC 

system in use. 

§ 236.1029.E1 Interference with the normal functioning of a PTC system or its components 

without first taking measures to provide for the safe movement of trains, 

locomotives, roadway workers, and/or on-track equipment that depend on the 

normal functioning of the system. 

§ 236.1029.F1 PTC system onboard apparatus not arranged so that each member of the train 

crew can receive the same PTC information. 

§ 236.1029.F2 PTC system onboard apparatus not arranged so that each member of the train 

crew can execute any functions necessary for that crewmember’s duties. 

§ 236.1029.F3 Locomotive engineer required to perform functions related to the PTC system 

while the train is moving that have the potential to distract him or her from the 

performance of other safety-critical duties. 

§ 236.1031 Previously approved PTC systems. 

(a) Any PTC system fully implemented and operational prior to March 16, 2010, may receive 
236-248 

PTC System Certification if the applicable PTC railroad, or one or more system suppliers and 

one or more PTC railroads, submits a Request for Expedited Certification (REC) letter to the 

Associate Administrator. The REC letter must do one of the following: 

(1) Reference a product safety plan (PSP) approved by FRA under subpart H of this part and 

include a document fulfilling the requirements under §§ 236.1011 and 236.1013 not already 

included in the PSP; 

(2) Attest that the PTC system has been approved by FRA and in operation for at least 5 

years and has already received an assessment of Verification and Validation from an independent 

third party under part 236 or a waiver supporting such operation; or 

(3) Attest that the PTC system is recognized under an Order issued prior to March 16, 2010. 

(b) If an REC letter conforms to paragraph (a)(1) of this section, the Associate Administrator, 

at his or her sole discretion, may also issue a new Type Approval for the PTC system. 

(c) In order to receive a Type Approval or PTC System Certification under paragraph (a) or 

(b) of this section, the PTC system must be shown to reliably execute the functionalities required 

by §§ 236.1005 and 236.1007 and otherwise conform to this subpart. 

(d) Previous approval or recognition of a train control system, together with an established 

service history, may, at the request of the PTC railroad, and consistent with available safety data, 

be credited toward satisfaction of the safety case requirements set forth in this part for the 

PTCSP with respect to all functionalities and implementations contemplated by the approval or 

recognition. 

(e) To the extent that the PTC system proposed for implementation under this subpart is 

different in significant detail from the system previously approved or recognized, the changes 

shall be fully analyzed in the PTCDP or PTCSP as would be the case absent prior approval or 

recognition. 

(f) As used in this section— 

(1) Approved refers to approval of a Product Safety Plan under subpart H of this part. 

(2) Recognized refers to official action permitting a system to be implemented for control of 

train operations under an FRA order or waiver, after review of safety case documentation for the 

implementation. 

(g) Upon receipt of an REC, FRA will consider all safety case information to the extent 

feasible and appropriate, given the specific facts before the agency. Nothing in this section limits 

re-use of any applicable safety case information by a party other than the party receiving: 

(1) A prior approval or recognition referred to in this section; or 

(2) A Type Approval or PTC System Certification under this subpart. 

Application:

This rule prescribes an expedited certification process in order to facilitate the ability of the 

railroads to leverage the results of PTC design, development, and implementation efforts that 

have been previously approved or recognized by FRA prior to the adoption of this subpart. 

Any PTC system fully implemented and operational prior to March 16, 2010, may receive PTC 

System Certification if the applicable PTC railroad, or one or more system suppliers and one or 

more PTC railroads, submits a Request for Expedited Certification (REC) letter to the Associate 

Administrator. 

CLASSIFICATION OF DEFECTS 

§ 236.1031.A1 Failure to provide the required information within an REC. 
236-249 

§ 236.1031.C1 Failure to show all required PTC system functionalities within the proposed 

system are executed reliably within an REC. 

§ 236.1031.E1 Failure to fully analyze within the PTCDP and/or PTCSP all significant changes 

for a proposed system for which an REC is requested. 

§ 236.1033 Communications and security requirements. 

(a) All wireless communications between the office, wayside, and onboard components in a 

PTC system shall provide cryptographic message integrity and authentication. 

(b) Cryptographic keys required under paragraph (a) of this section shall: 

(1) Use an algorithm approved by the National Institute of Standards (NIST) or a similarly 

recognized and FRA approved standards body; 

(2) Be distributed using manual or automated methods, or a combination of both; and 

(3) Be revoked: 

(i) If compromised by unauthorized disclosure of the cleartext key; or 

(ii) When the key algorithm reaches its lifespan as defined by the standards body responsible 

for approval of the algorithm. 

(c) The cleartext form of the cryptographic keys shall be protected from unauthorized 

disclosure, modification, or substitution, except during key entry when the cleartext keys and key 

components may be temporarily displayed to allow visual verification. When encrypted keys or 

key components are entered, the cryptographically protected cleartext key or key components 

shall not be displayed. 

(d) Access to cleartext keys shall be protected by a tamper resistant mechanism. 

(e) Each railroad electing to also provide cryptographic message confidentiality shall: 

(1) Comply with the same requirements for message integrity and authentication under this 

section; and 

(2) Only use keys meeting or exceeding the security strength required to protect the data as 

defined in the railroad’s PTCSP and required under § 236.1013(a)(7). 

(f) Each railroad, or its vendor or supplier, shall have a prioritized service restoration and 

mitigation plan for scheduled and unscheduled interruptions of service. This plan shall be 

included in the PTCDP or PTCSP as required by §§ 236.1013 or 236.1015, as applicable, and 

made available to FRA upon request, without undue delay, for restoration of communication 

services that support PTC system services. 

(g) Each railroad may elect to impose more restrictive requirements than those in this section, 

consistent with interoperability requirements specified in the PTCSP for the system. 

Application:

This rule provides specific communications security requirements for PTC system messages. 

All wireless communications between the office, wayside, and onboard components in a PTC 

system shall provide cryptographic message integrity and authentication. 

CLASSIFICATION OF DEFECTS 

§ 236.1033.A1 Wireless communications between office, wayside, and/or onboard components 

of PTC system do not provide cryptographic message integrity and 

authentication. 
236-250 

§ 236.1033.B1 Cryptographic key does not use an algorithm approved by the NIST or a 

similarly recognized and FRA approved standards body. 

§ 236.1033.B2 Failure to revoke a cryptographic key after the unauthorized disclosure of 

cleartext key. 

§ 236.1033.B3 Failure to revoke a cryptographic upon reaching its lifespan as defined by the 

standards body responsible for the approval of the algorithm. 

§ 236.1033.C1 Cleartext form of cryptographic keys not protected against unauthorized 

disclosure, modification, and/or substitution. 

§ 236.1033.C2 Cryptographically protected, cleartext key or key component displayed when 

encrypted keys or key components are entered. 

§ 236.1033.D1 Access to cleartext keys not protected by tamper resistant mechanism. 

§ 236.1033.E1 Cryptographic message confidentiality does not comply with the message 

integrity and/or authentication protocols. 

§ 236.1033.E2 Failure to use keys for cryptographic message confidentiality defined by 

railroad’s PTCSP/PTCDP. 

§ 236.1033.F1 Failure of a railroad, vendor, or supplier to develop a prioritized service and 

mitigation plan for scheduled or unscheduled interruption of service. 

§ 236.1033.F2 Prioritized service and mitigation plan for scheduled or unscheduled 

interruption of service not included in the PTCDP or PTCSP as required. 

§ 236.1033.F3 Railroad, vendor, or supplier prioritized service and mitigation plan for 

scheduled or unscheduled interruption of service not made available to FRA 

upon request. 

§ 236.1033.F4 Prioritized service and mitigation plan for scheduled or unscheduled 

interruption of service not made available to FRA upon request without undue 

delay for restoration of communication services supporting PTC system. 

§ 236.1035 Field testing requirements. 

(a) Before any field testing of an uncertified PTC system, or a product of an uncertified PTC 

system, or any regression testing of a certified PTC system is conducted on the general rail 

system, the railroad requesting the testing must provide: 

(1) A complete description of the PTC system; 

(2) An operational concepts document; 

(3) A complete description of the specific test procedures, including the measures that will be 

taken to protect trains and on-track equipment; 

(4) An analysis of the applicability of the requirements of subparts A through G of this part 

to the PTC system that will not apply during testing; 

(5) The date the proposed testing shall begin; 

(6) The test locations; and 
236-251 

(7) The effect on the current method of operation the PTC system will or may have under 

test. 

(b) FRA may impose additional testing conditions that it believes may be necessary for the 

safety of train operations. 

(c) Relief from regulations other than from subparts A through G of this part that the railroad 

believes are necessary to support the field testing, must be requested in accordance with part 211 

of this title. 

Application:

This section prescribes the requirements for initial field testing of an uncertified PTC system or a 

product of an uncertified PTC system, or any regression testing of a certified PTC system on the 

general rail system. 

 

CLASSIFICATION OF DEFECTS 

§ 236.1035.A1 Failure to provide a complete description of PTC system to FRA prior to field 

testing of uncertified PTC system, product of uncertified PTC system, or 

regression testing of certified PTC system conducted on the general rail system. 

§ 236.1035.A2 Failure to provide an Operational Concepts document to FRA prior to field 

testing of uncertified PTC system, product of uncertified PTC system, or 

regression testing of certified PTC system conducted on the general rail system. 

§ 236.1035.A3 Failure to provide a complete description of specific test procedures, including 

measures to be taken to protect trains and on-track equipment, to FRA prior to 

field testing of uncertified PTC system, product of uncertified PTC system, or 

regression testing of certified PTC system conducted on the general rail system. 

§ 236.1035.A4 Failure to provide an analysis of the applicability of the requirements of 

Subparts A thru G of this Part to the PTC system not applying during testing 

prior to field testing of uncertified PTC system, product of uncertified PTC 

system, or regression testing of certified PTC system conducted on the general 

rail system. 

§ 236.1035.A5 Failure to provide the date of proposed testing, test locations, and/or effect on 

current Method of Operation PTC system will or may have under test prior to 

field testing of uncertified PTC system, product of uncertified PTC system, or 

regression testing of certified PTC system conducted on the general rail system. 

§ 236.1035.B1 Failure to adhere to FRA imposed additional requirements for field testing of 

uncertified PTC system, product of uncertified PTC system, or regression 

testing of certified PTC system conducted on the general rail system. 

§ 236.1035.C1 Regulations not adhered to while field testing of uncertified PTC system, 

product of uncertified PTC system, or regression testing of certified PTC system 

conducted on the general rail system without prior FRA approval. 

§ 236.1037 Records retention. 

(a) Each railroad with a PTC system required to be installed under this subpart shall maintain 
236-252 

at a designated office on the railroad: 

(1) A current copy of each FRA approved Type Approval, if any, PTCDP, and PTCSP that it 

holds; 

(2) Adequate documentation to demonstrate that the PTCSP and PTCDP meet the safety 

requirements of this subpart, including the risk assessment; 

(3) An Operations and Maintenance Manual, pursuant to § 236.1039; and 

(4) Training and testing records pursuant to § 236.1043(b). 

(b) Results of inspections and tests specified in the PTCSP and PTCDP must be recorded 

pursuant to § 236.110. 

(c) Each contractor providing services relating to the testing, maintenance, or operation of a 

PTC system required to be installed under this subpart shall maintain at a designated office 

training records required under § 236.1039(b). 

(d) After the PTC system is placed in service, the railroad shall maintain a database of all 

safety-relevant hazards as set forth in the PTCSP and PTCDP and those that had not been 

previously identified in either document. If the frequency of the safety-relevant hazards exceeds 

the threshold set forth in either of these documents, then the railroad shall: 

(1) Report the inconsistency in writing by mail, facsimile, e-mail, or hand delivery to the 

Director, Office of Safety Assurance and Compliance, FRA, 1200 New Jersey Ave, SE, Mail 

Stop 25, Washington, DC 20590, within 15 days of discovery. Documents that are hand 

delivered must not be enclosed in an envelope; 

(2) Take prompt countermeasures to reduce the frequency of each safety-relevant hazard to 

below the threshold set forth in the PTCSP and PTCDP; and 

(3) Provide a final report when the inconsistency is resolved to the FRA Director, Office of 

Safety Assurance and Compliance, on the results of the analysis and countermeasures taken to 

reduce the frequency of the safety-relevant hazard(s) below the threshold set forth in the PTCSP 

and PTCDP. 

Application:

This section identifies reporting requirements and describes mandatory record maintenance for 

any railroad required to install a PTC system, or contractor providing services relating to the 

testing, maintenance, or operation of the required system. 

§ 236.1037.A1 Current copy of FRA approved Type Approval, PTCDP, and/or PTCSP not 

maintained at the designated railroad office. 

§ 236.1037.A2 Failure to maintain documentation demonstrating the PTCDP and/or PTCSP 

meet all the applicable safety requirements. 

§ 236.1037.A3 Failure to maintain documentation demonstrating the PTCDP and/or PTCSP 

meet all the applicable safety requirements at the designated railroad office. 

§ 236.1037.A4 PTC system operations and maintenance manual not maintained at the 

designated railroad office. 

§ 236.1037.A5 Training and test records not maintained at the designated railroad office. 

§ 236.1037.B1 PTCDP and/or PTCSP specified inspections and/or tests results not recorded. 
236-253 

§ 236.1037.C1 Training records for contractor providing services relating to testing, 

maintenance, or operation of PTC system not maintained at a designated office. 

§ 236.1037.D1 Failure to maintain, at the designated railroad office, a database of all safetyrelevant hazards, to include those identified in the PTCDP, PTCSP, and/or those 

not previously identified. 

§ 236.1037.D2 Failure to report to FRA any inconsistency pertaining to frequency of safetyrelevant hazards exceeding threshold established in PTCDP and/or PTCSP 

within 15 days of discovery. 

§ 236.1037.D3 Failure to report to FRA by an approved means, any inconsistency pertaining to 

frequency of safety-relevant hazards exceeding threshold established in PTCDP 

and/or PTCSP. 

 

§ 236.1037.D4 Failure to take prompt countermeasures to reduce the frequency of each safetyrelevant hazard above the threshold established in PTCDP and/or PTCSP. 

§ 236.1037.D5 Failure to provide a final report to FRA of results of analysis and 

countermeasures taken to reduce the frequency of safety-relevant hazards set 

forth in PTCDP and/or PTCSP. 

§ 236.1039 Operations and Maintenance Manual. 

(a) The railroad shall catalog and maintain all documents as specified in the PTCDP and 

PTCSP for the installation, maintenance, repair, modification, inspection, and testing of the PTC 

system and have them in one Operations and Maintenance Manual, readily available to persons 

required to perform such tasks and for inspection by FRA and FRA-certified state inspectors. 

(b) Plans required for proper maintenance, repair, inspection, and testing of safety critical 

PTC systems must be adequate in detail and must be made available for inspection by FRA and 

FRA-certified state inspectors where such PTC systems are deployed or maintained. They must 

identify all software versions, revisions, and revision dates. Plans must be legible and correct. 

(c) Hardware, software, and firmware revisions must be documented in the Operations and 

Maintenance Manual according to the railroad’s configuration management control plan and any 

additional configuration/revision control measures specified in the PTCDP and PTCSP. 

(d) Safety-critical components, including spare equipment, must be positively identified, 

handled, replaced, and repaired in accordance with the procedures specified in the PTCDP and 

PTCSP. 

(e) Each railroad shall designate in its Operations and Maintenance Manual an appropriate 

railroad officer responsible for issues relating to scheduled interruptions of service contemplated 

by § 236.1029. 

Application:

This section requires that each railroad develop a manual covering the requirements for the 

installation, maintenance, repair, modification, inspection, and testing of the PTC system and 

have them in one Operations and Maintenance Manual, readily available to persons required to 

perform such tasks, and for inspection by FRA and FRA-certified state inspectors. The railroad 

shall catalog and maintain these documents as specified in the PTCDP and PTCSP. 
236-254 

CLASSIFICATION OF DEFECTS 

§ 236.1039.A1 Failure to maintain and catalog all documentation pertaining installation, 

maintenance, repair, modification, inspection, and testing of PTC system in one 

operations and maintenance manual. 

§ 236.1039.A2 Failure to make the operations and maintenance manual available to persons 

required to perform PTC installation, maintenance, repair, modification, 

inspection, and testing tasks. 

§ 236.1039.A3 Operations and maintenance manual not made available to FRA and/or FRAcertified State inspectors during normal business hours. 

§ 236.1039.B1 Plans required for maintenance, repair, inspection, and/or testing of safetycritical PTC systems not developed. 

§ 236.1039.B2 Plans required for maintenance, repair, inspection, and/or testing of safetycritical PTC systems not of sufficient detail. 

§ 236.1039.B3 Plans required for maintenance, repair, inspection, and/or testing of safetycritical PTC systems not made available for inspection by FRA and/or FRAcertified State inspectors during normal business hours. 

§ 236.1039.B4 Plans required for maintenance, repair, inspection, and/or testing of safetycritical PTC systems do not identify software versions, revisions, and/or 

revision dates. 

§ 236.1039.B5 Plans required for maintenance, repair, inspection, and/or testing of safetycritical PTC systems not legible and/or correct. 

§ 236.1039.C1 Hardware, software, and/or firmware revisions not documented in PTC system 

operations and maintenance manual according to the railroad’s Configuration 

Management Control Plan and/or any additional configuration/revision control 

measures specified in the system PTCDP and/or PTCSP. 

§ 236.1039.D1 Safety-critical components of PTC system, including spare equipment, not 

positively identified, handled, replaced, or repaired in accordance with 

procedures specified in PTCDP and/or PTCSP. 

§ 236.1039.E1 Failure to designate a railroad officer responsible for issues relating to 

scheduled interruptions of service of PTC system in the PTC system operations 

and maintenance manual. 

§ 236.1041 Training and qualification program, general. 

(a) Training program for PTC personnel. Employers shall establish and implement training 

and qualification programs for PTC systems subject to this subpart. These programs must meet 

the minimum requirements set forth in the PTCDP and PTCSP in §§ 236.1039 through 

236.1045, as appropriate, for the following personnel: 

(1) Persons whose duties include installing, maintaining, repairing, modifying, inspecting, 
236-255 

and testing safety-critical elements of the railroad’s PTC systems, including central office, 

wayside, or onboard subsystems; 

(2) Persons who dispatch train operations (issue or communicate any mandatory directive 

that is executed or enforced, or is intended to be executed or enforced, by a train control system 

subject to this subpart); 

(3) Persons who operate trains or serve as a train or engine crew member subject to 

instruction and testing under part 217 of this chapter, on a train operating in territory where a 

train control system subject to this subpart is in use; 

(4) Roadway workers whose duties require them to know and understand how a train control 

system affects their safety and how to avoid interfering with its proper functioning; and 

(5) The direct supervisors of persons listed in paragraphs (a)(1) through (a)(4) of this section. 

(b) Competencies. The employer’s program must provide training for persons who perform 

the functions described in paragraph (a) of this section to ensure that they have the necessary 

knowledge and skills to effectively complete their duties related to operation and maintenance of 

the PTC system. 

Application:

This section sets forth the general/minimal requirements of an employer’s training and 

qualification programs for PTC systems subject to this subpart. These programs shall provide a 

description of the specific training necessary to ensure the safe installation, implementation, 

operation, maintenance, repair, inspection, testing, and modification of the PTC system, 

including central office, wayside, or onboard subsystems. This section does not restrict the 

employer from adopting additional and more stringent training requirements. 

CLASSIFICATION OF DEFECTS 

§ 236.1041.A1 Training and/or qualification program not established and/or implemented. 

§ 236.1041.A2 Training and/or qualification program does not meet minimum requirements set 

forth in a PTCDP and/or PTCSP for persons whose duties include installing, 

maintaining, repairing, modifying, inspecting, and testing safety-critical 

elements of the railroad’s PTC systems, including central office, wayside, or 

onboard subsystems. 

§ 236.1041.A3 Training and/or qualification program does not meet minimum requirements set 

forth in a PTCDP and/or PTCSP for persons who dispatch train operations 

(issue or communicate any mandatory directive that is executed or enforced, or 

is intended to be executed or enforced, by a train control system subject to this 

subpart). 

§ 236.1041.A4 Training and qualification program does not meet minimum requirements set 

forth in a PTCDP and/or PTCSP for persons who operate trains or serve as a 

train or engine crewmember subject to instruction and testing under Part 217 of 

this chapter, on a train operating in territory where a train control system subject 

to this subpart is in use. 

§ 236.1041.A5 Training and/or qualification program does not meet minimum requirements set 

forth in a PTCDP and/or PTCSP for roadway workers whose duties require 

them to know and understand how a train control system affects their safety and 

how to avoid interfering with its proper functioning. 
236-256 

§ 236.1041.A6 Training and/or qualification program does not meet minimum requirements set 

forth in a PTCDP and/or PTCSP for the direct supervisors of persons listed in 

this section. 

§ 236.1041.B1 Training and/or qualification program is not adequate to ensure personnel have 

necessary knowledge and skills to effectively complete required duties related 

to operation and maintenance of the PTC system. 

§ 236.1043 Task analysis and basic requirements. 

(a) Training structure and delivery. As part of the program required by § 236.1041, the 

employer shall, at a minimum: 

(1) Identify the specific goals of the training program with regard to the target population 

(craft, experience level, scope of work, etc.), task(s), and desired success rate; 

(2) Based on a formal task analysis, identify the installation, maintenance, repair, 

modification, inspection, testing, and operating tasks that must be performed on a railroad’s PTC 

systems. This includes the development of failure scenarios and the actions expected under such 

scenarios; 

(3) Develop written procedures for the performance of the tasks identified; 

(4) Identify the additional knowledge, skills, and abilities above those required for basic job 

performance necessary to perform each task; 

(5) Develop a training and evaluation curriculum that includes classroom, simulator, 

computer-based, hands-on, or other formally structured training designed to impart the 

knowledge, skills, and abilities identified as necessary to perform each task; 

(6) Prior to assignment of related tasks, require all persons mentioned in § 236.1041(a) to 

successfully complete a training curriculum and pass an examination that covers the PTC system 

and appropriate rules 

and tasks for which they are responsible (however, such persons may perform such tasks under 

the direct onsite supervision of a qualified person prior to completing such training and passing 

the examination); 

(7) Require periodic refresher training and evaluation at intervals specified in the PTCDP and 

PTCSP that includes classroom, simulator, computer-based, hands-on, or other formally 

structured training and testing, except with respect to basic skills for which proficiency is known 

to remain high as a result of frequent repetition of the task; and 

(8) Conduct regular and periodic evaluations of the effectiveness of the training program 

specified in § 236.1041(a)(1) verifying the adequacy of the training material and its validity with 

respect to current railroads PTC systems and operations. 

(b) Training records. Employers shall retain records which designate persons who are 

qualified under this section until new designations are recorded or for at least one year after such 

persons leave applicable service. These records shall be kept in a designated location and be 

available for inspection and replication by FRA and FRA-certified State inspectors. 

Application:

This section defines the requirements for a railroad’s training program training structure and 

delivery. As part of the program required by § 236.1041, the employer shall follow the 

directions within this section to include formal task analysis, written procedures for the 

performance, additional knowledge, skills, and abilities, along with refresher training and record 

retention. 
236-257 

CLASSIFICATION OF DEFECTS 

§ 236.1043.A1 Failure to identify specific goals of a PTC training program. 

§ 236.1043.A2 PTC training program is not based on a formal task analysis, identifying 

installation, maintenance, repair, modification, inspection, testing, and/or 

operating tasks that must be performed on the PTC systems. 

§ 236.1043.A3 PTC training program does not identify installation, maintenance, repair, 

modification, inspection, testing, and/or operating tasks that must be performed 

on the PTC systems, including failure scenarios and resulting expected actions. 

§ 236.1043.A4 Failure to develop written procedures for the performance of identified tasks. 

§ 236.1043.A5 Training program does not identify additional knowledge, skills, and/or abilities 

above those required for basic job performance necessary to perform each task. 

§ 236.1043.A6 Training and/or evaluation curriculum not developed. 

§ 236.1043.A7 Training and/or evaluation curriculum not sufficiently designed to impart the 

knowledge, skills, and/or abilities identified as necessary to perform each task. 

§ 236.1043.A8 PTC personnel assigned unsupervised related tasks without successfully 

completing a training curriculum and/or passing an examination. 

§ 236.1043.A9 Periodic refresher training and/or evaluation not provided as specified in a 

PTCDP and/or PTCSP. 

§ 236.1043.A10 Regular and/or periodic evaluations of the effectiveness of the training program 

not conducted. 

§ 236.1043.B1 Training records which designate persons qualified on PTC system not retained 

until new designation recorded or at least one year after such persons leave 

applicable service. 

§ 236.1043.B2 Training records not kept at designated location. 

§ 236.1043.B3 Training records not made available for inspection and/or replication by FRA 

and/or FRA-certified State inspectors during normal business hours. 

§ 236.1045 Training specific to office control personnel. 

(a) Any person responsible for issuing or communicating mandatory directives in territory 

where PTC systems are or will be in use shall be trained in the following areas, as applicable: 

(1) Instructions concerning the interface between the computer-aided dispatching system and 

the train control system, with respect to the safe movement of trains and other on-track 

equipment; 

(2) Railroad operating rules applicable to the train control system, including provision for 

movement and protection of roadway workers, unequipped trains, trains with failed or cut-out 
236-258 

train control onboard systems, and other on-track equipment; and 

(3) Instructions concerning control of trains and other on-track equipment in case the train 

control system fails, including periodic practical exercises or simulations, and operational testing 

under part 217 of this chapter to ensure the continued capability of the personnel to provide for 

safe operations under the alternative method of operation. 

(b) [Reserved] 

Application:

This section explains the training that must be provided to employees responsible for issuing or 

communicating mandatory directives. This training must include instructions concerning the 

interface between computer-aided dispatching systems and PTC systems as applicable to the safe 

movement of trains and other on-track equipment. In addition, the training must include 

operating rules that pertain to the train control system, including the provision for moving 

unequipped trains and trains on which the train control system has failed or been cut out en route. 

Additionally, it also includes periodic practical exercises or simulations and operational testing 

under Part 217 to assure that personnel are capable of providing for safe operations under 

alternative operation methods. 

CLASSIFICATION OF DEFECTS 

§ 236.1045.A1 Failure to train any person responsible for issuing and/or communicating 

mandatory directives in territory where PTC systems are or will be in use 

concerning the interface between the computer-aided dispatching system and 

the train control system, with respect to the safe movement of trains and other 

on-track equipment. 

§ 236.1045.A2 Failure to train any person responsible for issuing and/or communicating 

mandatory directives in territory where PTC systems are or will be in use on 

railroad operating rules applicable to the train control system, including 

provision for movement and protection of roadway workers, unequipped trains, 

trains with failed or cut-out train control onboard systems, and other on-track 

equipment. 

§ 236.1045.A3 Failure to train any person responsible for issuing and/or communicating 

mandatory directives in territory where PTC systems are or will be in use 

concerning control of trains and other on-track equipment in case the train 

control system fails, including 

periodic practical exercises or simulations, and operational testing under Part 

217 of this chapter to ensure the continued capability of the personnel to provide 

for safe operations under the alternative method of operation. 

§ 236.1047 Training specific to locomotive engineers and other operating personnel. 

(a) Operating personnel. Training provided under this subpart for any locomotive engineer 

or other person who participates in the operation of a train in train control territory shall be 

defined in the PTCDP as well as the PTCSP. The following elements shall be addressed: 

(1) Familiarization with train control equipment onboard the locomotive and the functioning 

of that equipment as part of the system and in relation to other onboard systems under that 

person’s control; 
236-259 

(2) Any actions required of the onboard personnel to enable, or enter data to, the system, 

such as consist data, and the role of that function in the safe operation of the train; 

(3) Sequencing of interventions by the system, including pre-enforcement notification, 

enforcement notification, penalty application initiation and post-penalty application procedures; 

(4) Railroad operating rules and testing (part 217) applicable to the train control system, 

including provisions for movement and protection of any unequipped trains, or trains with failed 

or cut-out train control onboard systems and other on-track equipment; 

(5) Means to detect deviations from proper functioning of onboard train control equipment 

and instructions regarding the actions to be taken with respect to control of the train and 

notification of designated railroad personnel; and 

(6) Information needed to prevent unintentional interference with the proper functioning of 

onboard train control equipment. 

(b) Locomotive engineer training. Training required under this subpart for a locomotive 

engineer, together with required records, shall be integrated into the program of training required 

by part 240 of this chapter. 

(c) Full automatic operation. The following special requirements apply in the event a train 

control system is used to effect full automatic operation of the train: 

(1) The PTCDP and PTCSP shall identify all safety hazards to be mitigated by the 

locomotive engineer. 

(2) The PTCDP and PTCSP shall address and describe the training required with provisions 

for the maintenance of skills proficiency. As a minimum, the training program must: 

(i) As described in § 236.1043(a)(2), develop failure scenarios which incorporate the safety 

hazards identified in the PTCDP and PTCSP including the return of train operations to a fully 

manual mode; 

(ii) Provide training, consistent with § 236.1047(a), for safe train operations under all failure 

scenarios and identified safety hazards that affect train operations; 

(iii) Provide training, consistent with § 236.1047(a), for safe train operations under manual 

control; and 

(iv) Consistent with § 236.1047(a), ensure maintenance of manual train operating skills by 

requiring manual starting and stopping of the train for an appropriate number of trips and by one 

or more of the following methods: 

(A) Manual operation of a train for a 4-hour work period; 

(B) Simulated manual operation of a train for a minimum of 4 hours in a Type I simulator as 

required; or 

(C) Other means as determined following consultation between the railroad and designated 

representatives of the affected employees and approved by FRA. The PTCDP and PTCSP shall 

designate the appropriate frequency when manual operation, starting, and stopping must be 

conducted, and the appropriate frequency of simulated manual operation. 

(d) Conductor training. Training required under this subpart for a conductor, together with 

required records, shall be integrated into the program of training required under this chapter. 

Application:

This section specifies minimum training requirements for locomotive engineers and other 

operating personnel who interact with PTC systems onboard the locomotive. This includes 

onboard train and engine crew members (i.e., conductors, brakemen, and assistant engineers). 

Training should include familiarization with the onboard PTC equipment and the functioning of 

that equipment as part of a train control system and its relationship to other onboard systems 

under that person’s control. The training program must cover all notifications by the system 

(i.e., onboard displays) and actions or responses to such notifications required by onboard 
236-260 

personnel, as well as how each action or response ensures proper operation of the system and 

safe operation of the train. The training requirements of this section must be fully integrated into 

the training requirements of 49 CFR Part 240. 

CLASSIFICATION OF DEFECTS 

§ 236.1047.A1 Training specific to locomotive engineers, and/or other persons participating in 

the operation of a train in train control territory, not conducted in accordance 

with training program as set forth in PTCDP and/or PTCSP. 

§ 236.1047.A2 Failure to train any locomotive engineer, and/or other person who participates in 

the operation of a train in train control territory, with the train control equipment 

onboard the locomotive and/or the functioning of that equipment as part of the 

system and in relation to other onboard systems under that person’s control. 

§ 236.1047.A3 Failure to train any locomotive engineer, and/or other person who participates in 

the operation of a train in train control territory, on all actions required of the 

onboard personnel to enable, and/or enter data to, the system, such as consist 

data, and the role of that function in the safe operation of the train. 

§ 236.1047.A4 Failure to train any locomotive engineer, and/or other person who participates in 

the operation of a train in train control territory, the sequencing of interventions 

by the system, including pre-enforcement notification, enforcement notification, 

penalty application initiation, and/or post-penalty application procedures. 

§ 236.1047.A5 Failure to train any locomotive engineer, and/or other person who participates in 

the operation of a train in train control territory, on the railroad operating rules 

and/or testing (Part 217) applicable to the train control system, including 

provisions for movement and protection of any unequipped trains, or trains with 

failed or cut-out train control onboard systems and other on-track equipment. 

§ 236.1047.A6 Failure to train any locomotive engineer, and/or other person who participates in 

the operation of a train in train control territory, on the means to detect 

deviations from proper functioning of onboard train control equipment and/or 

instructions regarding the actions to be taken with respect to control of the train 

and notification of designated railroad personnel. 

§ 236.1047.A7 Failure to train any locomotive engineer, and/or other person who participates in 

the operation of a train in train control territory, on the information needed to 

prevent unintentional interference with the proper functioning of onboard train 

control equipment. 

§ 236.1047.B1 Failure to integrate the locomotive engineer PTC training into the Part 240 

locomotive engineer training. 

§ 236.1047.C1 The PTCDP and/or PTCSP do not identify all safety hazards to be mitigated by 

the locomotive engineer in the event a train control system is used to effect the 

full automatic operation of the train. 

§ 236.1047.C2 The PTCDP and/or PTCSP do not address and/or describe the training required 

to include provisions for the maintenance of skill proficiency in the event a train 
236-261 

control system is used to effect the full automatic operation of the train. 

§ 236.1047.C3 Failure to develop training to address failure scenarios, which incorporate the 

safety hazards identified in the PTCDP and/or PTCSP, in the event a train 

control system is used to effect the full automatic operation of the train. 

§ 236.1047.C4 Failure to develop training to address returning of train operations to a fully 

manual mode in the event of a failure of the automatic operation of the train. 

§ 236.1047.C5 Failure to provide training to address all failure scenarios and/or identified 

safety hazards that affect train operations. 

§ 236.1047.C6 Failure to provide training for safe train operations under manual control. 

§ 236.1047 C7 Failure to provide training to ensure maintenance of manual train operating 

skills. 

§ 236.1047.C8 The PTCDP and/or PTCSP do not designate the appropriate frequency of 

manual and/or simulated manual operations. 

§ 236.1047.D1 Training and/or required training records specific to conductors participating in 

the operation of a train in train control territory not integrated into the PTC 

training program. 

§ 236.1049 Training specific to roadway workers. 

(a) Roadway worker training. Training required under this subpart for a roadway worker 

shall be integrated into the program of instruction required under part 214, subpart C of this 

chapter (“Roadway Worker Protection”), consistent with task analysis requirements of § 

236.1043. This training shall provide instruction for roadway workers who provide protection 

for themselves or roadway work groups. 

(b) Training subject areas. (1) Instruction for roadway workers shall ensure an 

understanding of the role of processor-based signal and train control equipment in establishing 

protection for roadway workers and their equipment. 

(2) Instruction for all roadway workers working in territories where PTC is required under 

this subpart shall ensure recognition of processor-based signal and train control equipment on the 

wayside and an understanding of how to avoid interference with its proper functioning. 

(3) Instructions concerning the recognition of system failures and the provision of alternative 

methods of on-track safety in case the train control system fails, including periodic practical 

exercises or simulations and operational testing under part 217 of this chapter to ensure the 

continued capability of roadway workers to be free from the danger of being struck by a moving 

train or other on-track equipment. 

Application:

This section specifies minimum training requirements for roadway workers. This training is 

designed to provide instructions for workers who obtain protection for roadway work groups or 

themselves and will specifically include instruction to ensure an understanding of the role of a 

PTC system in establishing protection for workers and their equipment, whether at a work zone 
236-262 

or while moving on-track equipment between work locations. Also, this section requires that 

training include recognition of PTC equipment on the wayside and how to avoid interference 

with its proper function. It also requires the railroad to incorporate appropriate training in the 

program of instruction under Part 214, Subpart C, Roadway Worker Protection. 

CLASSIFICATION OF DEFECTS 

§ 236.1049.A1 Failure to integrate the roadway worker PTC training into the program of 

instruction required under Part 214 (Roadway Worker Protection). 

§ 236.1049.B1 PTC training for roadway workers does not address the role of processor-based 

signal and train control equipment in establishing protection for roadway 

workers and their equipment. 

§ 236.1049.B2 PTC training for roadway workers does not address the recognition of 

processor-based signal and train control equipment on the wayside and/or an 

understanding of how to avoid interference with its proper functioning. 

§ 236.1049.B3 PTC training for roadway workers does not address the recognition of system 

failures and/or the provision of alternative methods of on-track safety in case 

the train control system fails. 

§ 236.1049.B4 PTC training for roadway workers does not address periodic practical exercises 

or simulations and/or operational testing under Part 217 of this chapter to ensure 

the continued capability of roadway workers to be free from the danger of being 

struck by a moving train or other on-track equipment. 

Appendix A to Part 236—Civil Penalty Schedule 

Refer to the latest edition of 49 CFR Part 236 – CIVIL PENALTIES 

Appendix B to Part 236—Risk Assessment Criteria 

The safety-critical performance of each product for which risk assessment is required under 

this part must be assessed in accordance with the following criteria or other criteria if 

demonstrated to the Associate Administrator for Safety to be equally suitable: 

 (a) How are risk metrics to be expressed? The risk metric for the proposed product must 

describe with a high degree of confidence the accumulated risk of a train system that operates 

over a life-cycle of 25 years or greater. Each risk metric for the proposed product must be 

expressed with an upper bound, as estimated with a sensitivity analysis, and the risk value 

selected must be demonstrated to have a high degree of confidence. 

 (b) How does the risk assessment handle interaction risks for interconnected 

subsystems/components? The safety-critical assessment of each product must include all of its 

interconnected subsystems and components and, where applicable, the interaction between such 

subsystems. 

 (c) How is the previous condition computed? Each subsystem or component of the previous 

condition must be analyzed with a Mean Time To Hazardous Event (MTTHE) as specified 

subject to a high degree of confidence. 

 (d) What major risk characteristics must be included when relevant to assessment? Each risk 
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calculation must consider the total signaling and train control system and method of operation, as 

subjected to a list of hazards to be mitigated by the signaling and train control system. The 

methodology requirements must include the following major characteristics, when they are 

relevant to the product being considered: 

 (1) Track plan infrastructure; 

 (2) Total number of trains and movement density; 

 (3) Train movement operational rules, as enforced by the dispatcher and train crew 

behaviors; 

 (4) Wayside subsystems and components; and 

 (5) Onboard subsystems and components. 

 (e) What other relevant parameters must be determined for the subsystems and components? 

The failure modes of each subsystem or component, or both, must be determined for the 

integrated hardware/software (where applicable) as a function of the Mean Time To Failure 

(MTTF) failure restoration rates, and the integrated hardware/software coverage of all processorbased subsystems or 

components, or both. Train operating and movement rules, along with components that are 

layered in order to enhance safety-critical behavior, must also be considered. 

 (f) How are processor-based subsystems/components assessed? (1) An MTTHE value must 

be calculated for each processor-based subsystem or component, or both, indicating the safetycritical behavior of the integrated hardware/software subsystem or component, or both. The 

human factor impact must be included in the assessment, whenever applicable, to provide an 

integrated MTTHE value. The MTTHE calculation must consider the rates of failures caused by 

permanent, transient, and intermittent faults accounting for the fault coverage of the integrated 

hardware/software subsystem or component, phased-interval maintenance, and restoration of the 

detected failures. 

 (2) MTTHE compliance verification and validation must be based on the assessment of the 

design for verification and validation process, historical performance data, analytical methods 

and experimental safety-critical performance testing performed on the subsystem or component. 

The compliance process must be demonstrated to be compliant and consistent with the MTTHE 

metric and demonstrated to have a high degree of confidence. 

 (g) How are non-processor-based subsystems/components assessed? (1) The safety-critical 

behavior of all non-processor-based components, which are part of a processor-based system or 

subsystem, must be quantified with an MTTHE metric. The MTTHE assessment methodology 

must consider failures caused by permanent, transient, and intermittent faults, phase-interval 

maintenance and restoration of failures and the effect of fault coverage of each non-processorbased subsystem or component. 

 (2) MTTHE compliance verification and validation must be based on the assessment of the 

design for verification and validation process, historical performance data, analytical methods 

and experimental safety-critical performance testing performed on the subsystem or component. 

The non-processor-based quantification compliance must be demonstrated to have a high degree 

of confidence. 

 (h) What assumptions must be documented? (1) The railroad shall document any assumptions 

regarding the reliability or availability of mechanical, electric, or electronic components. Such 

assumptions must include MTTF projections, as well as Mean Time To Repair (MTTR) 

projections, unless the risk assessment specifically explains why these assumptions are not 

relevant to the risk assessment. The railroad shall document these assumptions in such a form as 

to permit later automated comparisons with in-service experience (e.g., a spreadsheet). 

 (2) The railroad shall document any assumptions regarding human performance. The 
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documentation shall be in such a form as to facilitate later comparisons with in-service 

experience. 

 (3) The railroad shall document any assumptions regarding software defects. These 

assumptions shall be in a form which permits the railroad to project the likelihood of detecting an 

in-service software defect. These assumptions shall be documented in such a form as to permit 

later automated comparisons with in-service experience. 

 (4) The railroad shall document all of the identified safety-critical fault paths. The 

documentation shall be in such a form as to facilitate later comparisons with in-service faults. 

 

[70 FR 11052, March 07, 2005] 

Appendix C to Part 236—Safety Assurance Criteria and Processes 

 (a) What is the purpose of this appendix? This appendix seeks to promote full disclosure of 

safety risk to facilitate minimizing or eliminating elements of risk where practicable by 

providing minimum criteria and processes for safety analyses conducted in support of PSPs. The 

analysis required by this appendix is intended to minimize the probability of failure to an 

acceptable level, helping to optimize the safety of the product within the limitations of the 

available engineering science, cost, and other constraints. FRA uses the criteria and processes set 

forth in this appendix to evaluate analyses, assumptions, and conclusions provided in RSPP and 

PSP documents. An analysis performed under this appendix must: 

 1) Address each area of paragraph (b) of this appendix, explaining how such objectives are 

addressed or why they are not relevant, and 

 (2) Employ a validation and verification process pursuant to paragraph (c) of this appendix. 

 (b) What categories of safety elements must be addressed? The designer shall address each 

of the following safety considerations when designing and demonstrating the safety of products 

covered by Subpart H of this part. In the event that any of these principles are not followed, the 

PSP shall state both the reason(s) for departure and the alternative(s) utilized to mitigate or 

eliminate the hazards associated with the design principle not followed. 

 (1) Normal operation. The system (including all hardware and software) must demonstrate 

safe operation with no hardware failures under normal anticipated operating conditions with 

proper inputs and within the expected range of environmental conditions. All safety-critical 

functions must be performed properly under these normal conditions. Absence of specific 

operator actions or procedures will not 

prevent the system from operating safely. There must be no hazards that are categorized as 

unacceptable or undesirable. Hazards categorized as unacceptable must be eliminated by design. 

 (2) Systematic failure. It must be shown how the product is designed to mitigate or eliminate 

unsafe systematic failures-those conditions which can be attributed to human error that could 

occur at various stages throughout product development. This includes unsafe errors in the 

software due to human error in the software specification, design or coding phases, or both; 

human errors that could impact hardware design; unsafe conditions that could occur because of 

an improperly designed human-machine interface; installation and maintenance errors; and errors 

associated with making modifications. 

 (3) Random failure. (i) The product must be shown to operate safely under conditions of 

random hardware failure. This includes single as well as multiple hardware failures, particularly 

in instances where one or more failures could occur, remain undetected (latent) and react in 

combination with a subsequent failure at a later time to cause an unsafe operating situation. In 

instances involving a latent failure, a subsequent failure is similar to there being a single failure. 

In the event of a transient failure, and if so designed, the system should restart itself if it is safe to 

do so. Frequency of attempted restarts must be considered in the hazard analysis required by 
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§ 236.907(a)(8). 

 (ii) There shall be no single point failures in the product that can result in hazards 

categorized as unacceptable or undesirable. Occurrence of credible single point failures that can 

result in hazards must be detected and the product must achieve a known safe state before falsely 

activating any physical appliance. 

 (iii) If one non-self-revealing failure combined with a second failure can cause a hazard that 

is categorized as unacceptable or undesirable, then the second failure must be detected and the 

product must achieve a known safe state before falsely activating any physical appliance. 

 (4) Common Mode failure. Another concern of multiple failures involves common mode 

failures in which two or more subsystems or components intended to compensate one another to 

perform the same function all fail by the same mode and result in unsafe conditions. This is of 

particular concern in instances in which two or more elements (hardware or software, or both) 

are used in combination to ensure safety. If a common mode failure exists, then any analysis 

performed under this appendix cannot rely on the assumption that failures are independent. 

Examples include: the use of redundancy in which two or more elements perform a given 

function in parallel and when one (hardware or software) element checks/monitors another 

element (of hardware or software) to help ensure its safe operation. Common mode failure 

relates to independence, which must be ensured in these instances. When dealing with the 

effects of hardware failure, the designer shall address the effects of the failure not only on other 

hardware, but also on the execution of the software, since hardware failures can greatly affect 

how the software operates. 

 (5) External influences. The product must be shown to operate safely when subjected to 

different external influences, including: 

 (i) Electrical influences such as power supply anomalies/transients, abnormal/improper input 

conditions (e.g., outside of normal range inputs relative to amplitude and frequency, unusual 

combinations of inputs), including those related to a human operator, and others such as 

electromagnetic interference or electrostatic discharges, or both; 

 (ii) Mechanical influences such as vibration and shock; and 

 (iii) Climatic conditions such as temperature and humidity. 

 (6) Modifications. Safety must be ensured following modifications to the hardware or 

software, or both. All or some of the concerns identified in this paragraph may be applicable 

depending upon the nature and extent of the modifications. 

 (7) Software. Software faults must not cause hazards categorized as unacceptable or 

undesirable. 

 (8) Closed Loop Principle. The product design must require positive action to be taken in a 

prescribed manner to either begin product operation or continue product operation. 

 (9) Human Factors Engineering: The product design must sufficiently incorporate human 

factors engineering that is appropriate to the complexity of the product; the educational, mental, 

and physical capabilities of the intended operators and maintainers; the degree of required human 

interaction with the component; and the environment in which the product will be used. 

 (c) What standards are acceptable for verification and validation? (1) The standards 

employed for verification or validation, or both, of products subject to this subpart must be 

sufficient to support achievement of the applicable requirements of subpart H of this part. 

 (2) U.S. Department of Defense Military Standard (MIL-STD) 882C, “System Safety 

Program Requirements” (January 19, 1993), is recognized as providing appropriate risk analysis 

processes for incorporation into verification and validation standards. 

 (3) The following standards designed for application to processor-based signal and train 

control systems are recognized as acceptable with respect to applicable elements of safety 

analysis required by Subpart H of this part. The latest versions of the standards listed below 
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should be used unless otherwise provided. 

 (i) IEEE 1483-2000, Standard for the Verification of Vital Functions in Processor-Based 

Systems Used in Rail Transit Control. 

 (ii) CENELEC Standards as follows: 

 (A) EN50126: 1999, Railway Applications: Specification and Demonstration of Reliability, 

Availability, Maintainability and Safety (RAMS); 

 (B) EN50128 (May 2001), Railway Applications: Software for Railway Control and 

Protection Systems; 

 (C) EN50129: 2003, Railway Applications: Communications, Signaling, and Processing 

Systems-Safety Related Electronic Systems for Signaling; and 

 (D) EN50155:2001/A1:2002, Railway Applications: Electronic Equipment Used in Rolling 

Stock. 

 (iii) ATCS Specification 140, Recommended Practices for Safety and Systems Assurance. 

 (iv) ATCS Specification 130, Software Quality Assurance. 

 (v) AAR-AREMA 2005 Communications and Signal Manual of Recommended Practices, 

Part 17. 

 (vi) Safety of High Speed Ground Transportation Systems. Analytical Methodology for 

Safety Validation of Computer Controlled Subsystems. Volume II: Development of a Safety 

Validation Methodology. Final Report September 1995. Author: Jonathan F. Luedeke, Battelle. 

DOT/FRA/ORD-95/10.2. 

 (vii) IEC 61508 (International Electrotechnical Commission), Functional Safety of 

Electrical/Electronic/Programmable/Electronic Safety (E/E/P/ES) Related Systems, Parts 1-7 as 

follows: 

 (A) IEC 61508-1 (1998-12) Part 1: General requirements and IEC 61508-1 Corr. (1999-05) 

Corrigendum 1-Part 1:General Requirements. 

 (B) IEC 61508-2 (2000-05) Part 2: Requirements for electrical/electronic/ programmable 

electronic safety-related systems. 

 (C) IEC 61508-3 (1998-12) Part 3: Software requirements and IEC 61508-3 Corr.1 (1999-04) 

Corrigendum 1-Part3: Software requirements. 

 (D) IEC 61508-4 (1998-12) Part 4: Definitions and abbreviations and IEC 61508-4 Corr.1 

(1999-04) Corrigendum 1-Part 4: Definitions and abbreviations. 

 (E) IEC 61508-5 (1998-12) Part 5: Examples of methods for the determination of safety 

integrity levels and IEC 61508-5 Corr.1 (1999-04) Corrigendum 1 Part 5: Examples of methods 

for determination of safety integrity levels. 

 (F) IEC 61508-6 (2000-04) Part 6: Guidelines on the applications of IEC 61508-2 and -3. 

 (G) IEC 61508-7 (2000-03) Part 7: Overview of techniques and measures. 

 (4) Use of unpublished standards, including proprietary standards, is authorized to the extent 

that such standards are shown to achieve the requirements of this part. However, any such 

standards shall be 

available for inspection and replication by FRA and for public examination in any public 

proceeding before the FRA to which they are relevant. 

[70 FR 11052, March 07, 2005] 

Appendix D to Part 236—Independent Review of Verification and Validation 

 (a) What is the purpose of this appendix? This appendix provides minimum requirements for 

independent third-party assessment of product safety verification and validation pursuant to 

subpart H of this part. The goal of this assessment is to provide an independent evaluation of the 
236-267 

product manufacturer’s utilization of safety design practices during the product’s development 

and testing phases, as required by the applicable railroad's RSPP, the product PSP, the 

requirements of subpart H of this part, and any other previously agreed-upon controlling 

documents or standards. 

 (b) What general requirements apply to the conduct of third party assessments? (1) The 

supplier may request advice and assistance of the reviewer concerning the actions identified in 

paragraphs (c) through 

(g) of this appendix. However, the reviewer should not engage in design efforts, in order to 

preserve the reviewer’s independence and maintain the supplier’s proprietary right to the 

product. 

 (2) The supplier shall provide the reviewer access to any and all documentation that the 

reviewer requests and attendance at any design review or walkthrough that the reviewer 

determines as necessary to complete and accomplish the third party assessment. The reviewer 

may be accompanied by representatives of FRA as necessary, in FRA's judgment, for FRA to 

monitor the assessment. 

 (c) What must be done at the preliminary level? The reviewer shall evaluate with respect to 

safety and comment on the adequacy of the processes which the supplier applies to the design 

and development of the product. At a minimum, the reviewer shall compare the supplier 

processes with acceptable methodology and employ any other such tests or comparisons if they 

have been agreed to previously with FRA. Based on these analyses, the reviewer shall identify 

and document any significant safety vulnerabilities which are not adequately mitigated by the 

supplier’s (or user’s) processes. Finally, the reviewer shall evaluate the adequacy of the 

railroad’s RSPP, the PSP, and any other documents pertinent to the product being assessed. 

 (d) What must be done at the functional level? (1) The reviewer shall analyze the Preliminary 

Hazard Analysis (PHA) for comprehensiveness and compliance with the railroad’s RSPP. 

 (2) The reviewer shall analyze all Fault Tree Analyses (FTA), Failure Mode and Effects 

Criticality Analysis (FMECA), and other hazard analyses for completeness, correctness, and 

compliance with the railroad’s RSPP. 

 (e) What must be done at the implementation level? The reviewer shall randomly select 

various safety-critical software modules for audit to verify whether the requirements of the RSPP 

were followed. The number of modules audited must be determined as a representative number 

sufficient to provide confidence that all unaudited modules were developed in compliance with 

the RSPP. 

 (f) What must be done at closure? (1) The reviewer shall evaluate and comment on the plan 

for installation and test procedures of the product for revenue service. 

 (2) The reviewer shall prepare a final report of the assessment. The report shall be submitted 

to the railroad prior to the commencement of installation testing and contain at least the 

following information: 

 (i) Reviewer’s evaluation of the adequacy of the PSP, including the supplier’s MTTHE and 

risk estimates for the product, and the supplier’s confidence interval in these estimates; 

 (ii) Product vulnerabilities which the reviewer felt were not adequately mitigated, including 

the method by which the railroad would assure product safety in the event of a hardware or 

software failure (i.e., how does the railroad assure that all potentially hazardous failure modes 

are identified?) and the method by which the railroad addresses comprehensiveness of the 

product design for the requirements of the operations it will govern (i.e., how does the railroad 

assure that all potentially hazardous operating circumstances are identified? Who records any 

deficiencies identified in the design process? Who tracks the correction of these deficiencies and 

confirms that they are corrected?); 

 (iii) A clear statement of position for all parties involved for each product vulnerability cited 

by the reviewer; 
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 (iv) Identification of any documentation or information sought by the reviewer that was 

denied, incomplete, or inadequate; 

 (v) A listing of each RSPP procedure or process which was not properly followed; 

 (vi) Identification of the software verification and validation procedures for the product’s 

safety-critical applications, and the reviewer’s evaluation of the adequacy of these procedures; 

 (vii) Methods employed by the product manufacturer to develop safety-critical software, such 

as use of structured language, code checks, modularity, or other similar generally acceptable 

techniques; and 

 (viii) Method by which the supplier or railroad addresses comprehensiveness of the product 

design which considers the safety elements listed in paragraph (b) of Appendix C to this part. 

[70 FR 11052, March 07, 2005] 

Appendix E to Part 236—Human-Machine Interface (HMI) Design 

(a) What is the purpose of this appendix? The purpose of this appendix is to provide HMI 

design criteria which will minimize negative safety effects by causing designers to consider 

human factors in the development of HMIs. 

 (b) What is meant by “designer” and “operator”? As used in this section, “designer” means 

anyone who specifies requirements for-or designs a system or subsystem, or both, for-a product 

subject to subpart H of this part, and “operator” means any human who is intended to receive 

information from, provide information to, or perform repairs or maintenance on a signal or train 

control product subject to Subpart H of this part. 

 (c) What kinds of human factors issues must designers consider with regard to the general 

function of a system? (1) Reduced situational awareness and over-reliance. HMI design must 

give an operator active functions to perform, feedback on the results of the operator’s actions, 

and information on the automatic functions of the system as well as its performance. The 

operator must be “in-the-loop.” Designers shall consider at minimum the following methods of 

maintaining an active role for human operators: 

 (i) The system must require an operator to initiate action to operate the train and require an 

operator to remain “in the loop” for at least 30 minutes at a time; 

 (ii) The system must provide timely feedback to an operator regarding the system’s 

automated actions, the reasons for such actions, and the effects of the operator’s manual actions 

on the system; 

 (iii) The system must warn operators in advance when they require an operator to take 

action; and 

 (iv) HMI design must equalize an operator’s workload. 

 (2) Expectation of predictability and consistency in product behavior and communications. 

HMI design must accommodate an operator’s expectation of logical and consistent relationships 

between actions and results. Similar objects must behave consistently when an operator 

performs the same action upon them. 

 (3) Limited memory and ability to process information. (i) HMI design must minimize an 

operator’s information processing load. To minimize information processing load, the designer 

shall: 

 (A) Present integrated information that directly supports the variety and types of decisions 

that an operator makes; 

 (B) Provide information in a format or representation that minimizes the time required to 

understand and act; and 

 (C) Conduct utility tests of decision aids to establish clear benefits such as processing time 

saved or improved quality of decisions. 
236-269 

 (ii) HMI design must minimize the load on an operator’s memory. 

 (A) To minimize short-term memory load, the designer shall integrate data or information 

from multiple sources into a single format or representation (“chunking”) and design so that 

three or fewer “chunks” of information need to be remembered at any one time. 

 (B) To minimize long-term memory load, the designer shall design to support recognition 

memory, design memory aids to minimize the amount of information that must be recalled from 

unaided memory when making critical decisions, and promote active processing of the 

information. 

 (4) Miscellaneous Human Factors Concerns. System designers shall: 

 (i) Design systems that anticipate possible user errors and include capabilities to catch errors 

before they propagate through the system; 

 (ii) Conduct cognitive task analyses prior to designing the system to better understand the 

information processing requirements of operators when making critical decisions; and 

 (iii) Present information that accurately represents or predicts system states. 

 (d) What kinds of HMI design elements must a designer incorporate in the development of 

on-board train displays and controls? (1) Location of displays and controls. Designers shall: 

 (i) Locate displays as close as possible to the controls that affect them; 

 (ii) Locate displays and controls based on an operator’s position; 

 (iii) Arrange controls to minimize the need for the operator to change position; 

 (iv) Arrange controls according to their expected order of use; 

 (v) Group similar controls together; 

 (vi) Design for high stimulus-response compatibility (geometric and conceptual); 

 (vii) Design safety-critical controls to require more than one positive action to activate (e.g., 

auto stick shift requires two movements to go into reverse); and 

 (viii) Design controls to allow easy recovery from error. 

 (2) Information management. HMI design must: 

 (i) Display information in a manner which emphasizes its relative importance; 

 (ii) Comply with the ANSI/HFS 100-1988 standard; 

 (iii) Design for display luminance of the foreground or background of at least 35 cd/m2 (the 

displays should be capable of a minimum contrast 3:1 with 7:1 preferred, and controls should be 

provided to adjust the brightness level and contrast level); 

 (iv) Design the interface to display only the information necessary to the user; 

 (v) Where text is needed, using short, simple sentences or phrases with wording that an 

operator will understand; 

 (vi) Use complete words where possible. Where abbreviations are necessary, choose a 

commonly accepted abbreviation or consistent method and select commonly used terms and 

words that the operator will understand; 

 (vii) Adopt a consistent format for all display screens by placing each design element in a 

consistent and specified location; 

 (viii) Display critical information in the center of the operator’s field of view by placing 

items that need to be found quickly in the upper left hand corner and items which are not timecritical in the lower right hand corner of the field of view; 

 (ix) Group items that belong together; 

 (x) Design all visual displays to meet human performance criteria under monochrome 

conditions and add color only if it will help the user in performing a task, and use color coding as 

a redundant coding technique; 

 (xi) Limit the number of colors over a group of displays to no more than seven; 

 (xii) Design warnings to match the level of risk or danger with the alerting nature of the 

signal; 
236-270 

 (xiii) With respect to information entry, avoid full QWERTY keyboards for data entry; and 

 (xiv) Use digital communications for safety-critical messages between the locomotive 

engineer and the dispatcher. 

 (e) What kinds of HMI design elements must a designer consider with respect to problem 

management? (1) HMI design must enhance an operator’s situation awareness. An operator 

must have access to: 

 (i) Knowledge of the operator’s train location relative to relevant entities; 

 (ii) Knowledge of the type and importance of relevant entities; 

 (iii) Understanding of the evolution of the situation over time; 

 (iv) Knowledge of the roles and responsibilities of relevant entities; and 

 (v) Knowledge of expected actions of relevant entities. 

 (2) HMI design must support response selection and scheduling. 

 (3) HMI design must support contingency planning. 

[70 FR 11052, March 7, 2005] 
Reference A

Fouling Section Clearance

Point Measurement Diagram

Reference B

Copy of January 3, 1985  

Himmel Letter








Reference C

 FRA Home Page – Web‐link to Technical Bulletins; 

 http://www.fra.dot.gov/eLib/Find#p1_z50_lCT_s59

FRA Home Page ‐ Web‐link to Safety Advisories;

 http://www.fra.dot.gov/eLib/Find#p1_z50_s59_lSA