Methods of Operation and Signal Systems

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Learning Objectives
        - Understand the various methods of operation and signal systems used on today’s railroads.

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CAUTION

The following presentation was developed to provide general information only. For detailed compliance information please refer to 49 CFR 236 – Rules, Standards and Instructions, Subpart D and the S&TC technical manual.  It is recommended that each employee refer to appropriate manuals and regulations when dealing with any specific issue.

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When in doubt, go to the book!

Information

The FRA Rules, Standards, and Instructions are considered to be the minimum standard allowed for the installation, inspection, maintenance, and repair of signal and train control systems, devices, and appliances.  Each railroad may adopt more stringent standards. Refer to your railroad’s signal standard and instruction manual for further guidance.

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Method Of Operation & Signal Systems

The following presentation contains generic descriptions of different railroad methods of operation to be used for study purposes only.  If questions arise regarding a specific railroad’s method of operation please consult the appropriate timetable, FRA regulation 49 CFR 236.0, or your supervisor for further guidance.

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Rail operations result of a symbiotic relationship between the transportation, mechanical, and engineering branches of a railroad.  Engineering and mechanical assets provide the facilities, equipment, and infrastructure; while the transportation branch fulfills the railroads principle function of transporting people and freight.  Without the mechanical and engineering functions the transportation function cannot exist; and without the transportation function there is no reason for the mechanical and engineering functions to exist.

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Method Of Operation & Signal Systems
        - Method of Operation and Signal Systems.

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When railroading first began with one locomotive on one track there was no need for a method of operation.  When the second locomotive  was added the possibility existed for a collision.  

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Method Of Operation & Signal Systems

Two trains which are not in the same place at the same time cannot collide!

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To prevent such an occurrence the railroad s developed rules for operating with over time evolved into methods of operation.  As you can image these methods of operation generally started out simple and became more complexed over time.  The exception to that rule is when technology advances to a point where dramatic changes are made.

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Method Of Operation & Signal Systems

“Method of Operation” is a term which is best defined as the means by which a train has authority for movement.

The method and the specified limits are usually listed in the railroad’s timetable for each district or subdivision.

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Method Of Operation & Signal Systems

“Signal System” is a term which refers to the type of system (or systems) in use on a specified territory.

Signal systems, interlockings and special signal arrangements are listed in the railroad’s timetable for each district or subdivision.

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Non-signal Operating Systems
        - Yard Limits
        - Timetable Operation
        - Train Order
        - Manual Block System 
        - Track Warrant/Track Permit
        - Direct Traffic Control

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All non-signal methods of operation are all manual in nature and require three fundamental components:
          - A process.
          - Standardized communication system.
          - Humans.

The process may be any of those listed on this slide.

Earlier methods of operation separated trains by time.  Later, technology allowed these method to evolve into separating trains by space.  This evolution greatly improvedd the safety and efficiency of train operation. 

Standardized communications may be in the form of verbal or written communication, an understanding of the vernacular or terminology used in the operation, or simple a common understanding of and adherence to the applicable rules.

Humans are the strength and weakness of the system.  The strength of the system by being the most adaptable component within the system – human perceive the situation, analyze the situation, and react to the situation – they think!  They are the weakest part of the system because they can and do err.

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Automatic Block Signals
        - Automatic Block System (ABS)
        - Multiple Track (Current of Traffic)
        - Absolute Permissive Block

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Automatic signal systems function based on the inherent characteristics that system was designed to fulfill.  They perform their designed functions very well and can repeat that function over and over.  However, they cannot think and therefore cannot adapt to changes in the operational environment.  Because they cannot “think” automatic block signal systems cannot be a method of operation and signal indication only cannot authorize train movements with only a few exceptions*.  Automatic signal systems are generally used as a supplement to the method of operation to enhance safety and improve efficiency.

*NOTE: There is an exception.  In certain double track ABS territories the rules (formerly Rule 251 and 261) allows a train to operate on signal indication, but only with the current of traffic established for the track.  Rule 251 is usually used with Double Track. ("Double Track" is not defined the same as "Two Main Tracks" on Western roads.  Double Track has a designated current of traffic for each track, and is signaled only for trains moving in that direction.  Two or more Main Tracks are each signaled for movement in either direction).  The signals in Rule 251 territory are controlled by track occupancy, not the dispatcher. This type of operation is common on commuter lines where most or all trains operate at the same speed. 

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Operation by Signal Indication
        - Intelockings
        - Traffic Control System

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Interlockings and Traffic Control Systems have two distinct components:
          - Machine component – mechanical, electric, electronic (digital) logic that only allows events to occur in a safe and proper sequence.
          - Human component – observes the changing operational environment, analyzes the situation, makes decisions, and initiate actions.

Because a human decision-maker is part of these systems they can be used a method of operation whereby trains movements are authorized by signal indication only.

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Yard Limits

Within yard limits, the main track may be used by trains or engines, not protecting (note: no flag protection) against other trains or engines. Engines must give way to trains as soon as practicable upon their approach. Movements within yard limits must be made at restricted speed, unless the main track is known to be clear by a block signal displaying a clear (e.g. green) as part of its aspect.

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Yard Limits may be used on the main track with or without a block signal system.  Usually, this type of operation requires that a train or engine operating using yard limit rules must clear the main track a specified number of minutes before the arrive of other trains. 

NOTE:  The Yard Limit method of operation is not compatible with Interlocking, Traffic Control System, or Controlled Block Systems.  The reason for this prohabition is that the human decision-maker must control entrance into and movement through their area of responsibility.  They cannot plan for and safely and efficiently control train movements on their territory if there are uncontrolled movement entering without authority.

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What is the allowable speed here? Refer to 49 CFR 236.0

Non-signal (Dark) territory

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Non-signal territory is  a section of track that utilizes a method of train operation with a block signal system.

Passenger trains are limited to 59 mph and freight trains are limited to 49 mph. 

(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 permitted to operate 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. 

Timetable Operation
        - Timetable operation is a system where train movements are authorized by being scheduled in the timetable. 
        - Any deviations from the timetable (delayed, extra, or annulled trains), would be provided for by train orders. 
        - This used to be a standard method of train operation throughout the country, now is quite rare.

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The simplest form of operation is to run the system according to a timetable (Time separation). Timetable operation was the normal mode of operation in North America in the early days of the railroad.  Every train crew understands and adheres to a fixed schedule.  Trains may only run on each track section at a scheduled time, during which they have 'possession' and no other train may use the same section.

When trains run in opposite directions on a single-track railroad, meeting points ("meets") are scheduled, at which each train must wait for the other at a passing place.  Neither train is permitted to move before the other has arrived.  

The timetable system has several disadvantages.  First, there is no positive confirmation that the track ahead is clear, only that it is scheduled to be clear.  The system does not allow for engine failures and other such problems, but the timetable is set up so that there should be sufficient time between trains for the crew of a failed or delayed train to walk far enough to set warning flags, flares, and torpedoes to alert any other train crew.

A second problem is the system's inflexibility.  Trains cannot be added, delayed, or rescheduled without advance notice.

A third problem is a corollary of the second: the system is inefficient.  To provide flexibility, the timetable must give trains a broad allocation of time to allow for delays, so the line is in the possession of each train for longer than is otherwise necessary.

Nonetheless, this system permits operation on a vast scale, with no requirements for any kind of communication that travels faster than a train. 

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Technology and Methods of Operation

Telegraph on Early Railroads
        - 1840s – Erie Railroad begins installing telegraph.
        - 1851 – Erie Railroad issues first telegraphic train order.

First Telegraphic Train Order
        - Superintendent Charles Minot of the Erie Railroad was on a train at Turner, New York waiting for a delayed eastbound train.
        - He wired Monroe, New York asking if the train had arrived yet.
        - Upon receiving a negative reply, he sent the following historic wire.

To Agent and Operator at Goshen:

Hold the train for further orders.

Charles Minot, Superintendent

He then hand wrote the following order:

To Conductor and Engineer, Day Express:

Run to Goshen regardless of opposing train.

Charles Minot, Superintendent

September 22, 1851, Superintendent Charles Minot issues the first telegraphic train order.

NOTE:  On September 22, 1851, Minot was in a parked passenger train at Turner Station.  He glanced out the window of the train and saw the new telegraph wires.  Departing the train, Minot ran into the station, got on the new telegraph, and wired the next station along the line, Monroe, to see if the eastbound train to Piermont-on-Hudson had gone past.  The station agent said no. At that point, Minot ordered the engineer of the train to proceed on their way to Goshen.  The engineer refused to take Minot's order, and instead, Minot got into the cab car himself and drove the train himself to Port Jervis, hours ahead of the planned scheduled time of arrival.

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The Train Order Method of Train Operation was born on September 22, 1851

This Method of Operation was replaced by 

Track Warrant Control and Direct Traffic Control

In the 1980s – 90s.

Popular on single track lines in North America up until the 1980s, Train Order operation was less a block system and more of a system of determining which trains would have the right of way when train movements would come into conflict.  Trains would make use of a predetermined operating plan known as the timetable which made use of fixed passing locations often referred to as stations.  Amendments to the operating plan would come from a train dispatcher in the form of train orders, transmitted to the trains via intermediaries known as agents or operators at train order stations.

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Train Order
        - The train order method of operation is an older written form authorizing train movements.
        - This method required train order operators to be stationed along the route to pass orders to the trains.
        - Train orders have been mostly replaced with Track Warrants, Track Permits, and Direct Traffic Control systems.

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The train order method of operation is the first evolution from the timetable method.  Based on the new technology of the telegraph, railroads where able to communicate train location information.  With the advent of the telegraph in 1851, it was possible to communicate faster than the speed of the fastest train.

A more sophisticated system became possible that overcame the disadvantages of the timetable method of operation.  The telegraph allowed for the modification and dissemination of any timetable changes.  These modifications became known as train orders.  Train orders allow for the cancellation, rescheduling and addition of train services.

The train order method meant that train crews generally received their orders at the next station at which they stopped, or were sometimes handed up to a locomotive 'on the run' via a long staff.  Train orders allowed dispatchers to set up meets at sidings, force a train to wait in a siding for a priority train to pass, and to maintain at least one block spacing between trains going the same direction.  Train order operators at stations along the route became the eyes and ears of the dispatcher allowing for more efficient train operation planning.

The train order method provides the means to deal with changes in operating conditions as they arise. Orders modify the established timetable. Among the functions a train order can perform are:
          - Creating a train not provided for by the timetable (a so-called "extra").
          - Aa train provided by the timetable.
          - Creating sections of a schedule (in essence "cloning" a train's schedule and class when, for example, too much traffic exists to be handled by a single train).
          - Setting meeting points between extras since they have no timetable schedule.
          - Altering timetable meeting points (for example when one train is late and adhering to the timetable meeting point would cause delays for other trains).
          - Altering the schedule of a train to allow other trains to run with respect to the altered schedule rather than that given in the timetable.
          - Giving a train rights over another train that ordinarily has timetable superiority.
          - Conveying warnings about temporary conditions such as temporary speed limits, track conditions or hazards which might affect the safety of trains or train crews.

The train order method had the inherent danger of ambiguous or conflicting instructions being given resulting in was is referred to as a “lap order” where two trains are allowed into the same block in opposite directions.  

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Manual Block System
        - Manual Block is a means of controlling movements of trains in the same direction without automatic block signals. 
        - Sections of railroad would be divided into blocks, which extended between stations or manual interlocking towers attended by operators. 
        - Signals would be controlled by the operators.

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          - Certain systems permanently in place on today’s railroads may qualify as a Manual Block System.
          - Systems which qualify may depend on a review by the S&TC and Operating Practices division in Headquarters.
          - These systems may allow speeds greater than 59/49 MPH .
          - A train would be permitted to pass a signal, only when the operators at both ends of the block agree that the block is unoccupied. 

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Manual Block System

What is the allowable speed with a manual block system permanently in effect? Refer to 49 CFR 236.0.

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More than 60 mph for passenger trains and more than 50 mph for freight as determined by the class of track.

§ 236.0 Applicability, minimum requirements, and penalties.

(a) Except as provided in paragraph (b) of this section, this part applies to all railroads and any person as defined in paragraph (f) of this section. 

(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 permitted to operate 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. 

Technology and Methods of Operation
        - American railroads led the way in developing advanced communications systems.
        - In the 1950s railroads introduced the widespread use of microwave and radio communication.
        - By the 1980s these system led to a fundamental change in rail operations.

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The wide spread use of microwave and radio communication system gave railroads the technological capacity to fundamentally change the way they operated in timetable/train order territory and Block Register Territory (BRT).  The ability of the dispatcher to talk directly to the train crews brought about the demise of timetable/train order and BRT operations in favor of voice control systems such as Track Warrant Control and Direct traffic Control.  

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Track Warrant Control (TWC)
        - TWC utilizes written forms authorizing trains to occupy designated track segments. 
        - Any two identifiable points on the railroad can be used to designate the segments.
        - Train dispatchers may transmit instructions by radio to crew members, who will write this information on these forms.
        - Sometimes referred to as Track Permit method.

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Track Warrant Control. Track Warrant Control authorizes the dispatcher to verbally instruct trains to proceed, usually via radio.  The dispatcher selects the stations or mileposts between which the train may move - a segment of track known as the authority limit.  Warrants may contain conditions such as "not in effect until after the arrival of..."  The train crew writes the instructions on a Track Warrant Form and repeats them to the dispatcher for verification.  Nothing prevents the dispatcher from erroneously issuing overlapping or conflicting warrants, though most large railroads now require him to simultaneously key the authority into a computer, which checks for conflicts.  TWC is used by most Western roads and Norfolk Southern on medium- and low-density lines.  

While TWC is inherently unsafe (due to the high dependency on human performance), several safeguards reduce the risk of human error.  These safeguard include:
          - Standardize Track Warrant forms with check boxes.
          - Standardized communications protocols.
          - Re-back  verification.

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Direct Traffic Control (DTC)
        - DTC is a system where a portion of railroad is divided into "blocks", each of which has a name. 
        - Train dispatchers will authorize the occupancy of blocks by naming the blocks authorized.

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Direct Traffic Control. Direct Traffic Control is similar in execution and application to TWC, but the railroad is divided into pre-defined "blocks." The dispatcher authorizes a train to proceed in one or more of the blocks, but does not have the flexibility in the selection of authority boundaries available under TWC.  Kansas City Southern, Union Pacific, and CSX are three railroads that use DTC on portions of their routes. 

Like TWC, DTC is inherently unsafe (due to the high dependency on human performance), however, several safeguards reduce the risk of human error.  These safeguard include:
          - Standardize Track Warrant forms with check boxes.
          - Standardized communications protocols.
          - Re-back  verification.
          - Clear signage that identifies the limits of specifically named blocks.

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Automatic Block Signal Systems

These systems are used as a safety supplement to other methods of operation, e.g. Train Orders, TWC, etc.

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Automatic Block System (ABS)
        - ABS is not a method of train operation, but can be used as a supplement to provide safer and more efficient train movements.
        - Sections of railroad would be divided into blocks, and automatic signals at the entrance of each block would convey the presence of trains ahead.

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Automatic Block Signal Systems

Automatic Block Signal Systems are usually designed for a specific application, e.g. single track, double track, etc.

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In its simplest form Automatic Block Signal Systems consist of two opposing signals at the entrance to a section of signal track.  Any time that the track section is occupied the signals will be placed at “Stop”.  These signals are referred to as “Head Block Signals”.

ABS on Multiple Track
        - Each track is equipped with automatic signals for a designated direction, or "current of traffic". 
        - If necessary to operate trains against current of traffic, one of the methods for non-signaled trackage must be used.

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Automatic Block Signal Systems
        - Automatic Block Signal Systems
        - Double Track – Current of Traffic.  Trains normally run in only one direction.

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Two tracks signal for traffic in one direction only is referred to as “Double Track” and trains operated with the current of traffic.

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Automatic Block Signal Systems

Current of traffic ABS is designed for movements in one direction on each track. The authority for movement is usually by train order, track warrant, etc., supplemented by the ABS system. 

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In double track, direction of traffic territory train movements are normally authorized by track warrants or other track authorities.

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Automatic Block Signal Systems

Current of traffic ABS is not designed for movements in reverse direction, this must be accomplished by train order, track warrant, etc. to be done safely. (Wrong Main Moves, same as running in non-signal territory?)

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Trains operating against the current of traffic must operate as if they were in non-signal territory.

Absolute Permissive Block
        - APB signals regulate movements in the same direction, and protect against movements of the opposite direction. 
        - APB is not a method of operation, but supplements some other type of train movement authority by increasing safety and efficiency.

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Automatic Permissive Block is a modification of ABS that adds intermediate signals to allow for more efficient operation.  

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Absolute permissive Block Signal Systems

Absolute Permissive Block Signal Systems are designed to protect train movements from opposing traffic and to allow following movements.

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In APB territory the opposing head block signal and all opposing intermediate signals are set to “Stop” when a train enters the track section.  As the train moves through the block the intermediate signals progressively become less restrictive allowing for following trains.

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Interlocking Signal Systems

A method of operation whereby train movements using routes of an interlocking are governed by signal indications which supersede the timetable superiority of trains within interlocking limits. The interlocking signal (when lined) establishes authority for movement into and through interlocking limits.  

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Interlocking (manual)
        - Interlockings are location where switches and signals are controlled by a control operator. 
        - Switches and signals are "interlocked", meaning that they cannot be set for conflicting or opposing movements.
        - They are so arranged that when a signal is cleared for a train movement no switch in the route can be changed.

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Manual Interlocking Plants are a location where switches and signals are controlled remotely or from a nearby tower.  Switches and signals are "interlocked", meaning that they cannot be set for conflicting or opposing movements.  All train movements are authorized by signal indication.

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Interlocking (automatic)
        - Interlocking arranged so that an approaching train initiates a request for a route. 
        - The system automatically checks for:
        - Plant not occupied
        - Conflicting and opposing movements.
        - Conflicting and opposing signals at “Stop”.
        - Plant not locked.
        - If these conditions are met the approaching train receives a proceed signal.

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Automatic Interlocking Plants (AIP) are used at railroad/railroad crossings at grade.  They are usually employed at locations where one or both railroads have relatively low traffic.  Normally, all the absolute signals at an AIP are set to “Stop”.  When a train approaches the AIP the presence of the train request a route through the plant.  If all the conflicting and opposing signals are at “Stop”, no train is occupying the interlocking limits, and the interlocking is not locked, a signal in automatically cleared for the approaching train.

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Interlocking Signal System

Signal indication of an Interlocking Signal System will be the authority for train movement at interlockings. (see 236.301)

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All train movements through and automatic interlocking plant are authorized by signal indication only.

TCS combines Two Proven Technologies

Interlocking

Automatic Block

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And adds in a communications system.

After the invention of the telephone in 1875, it slowly began to replace the telegraph as a means of railroad communications.  The ingredients now existed for a new method of train operation:
          - Interlocking at control points.
          - Automatic block Signals for movements between stations.
          - Telephone for communicating between the dispatcher and train crews.

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Traffic Control System - 1927
        - The first Traffic Control System (TCS) System was installed in 1927 on the New York Central Railroad between Stanley and Berwick, Ohio.
        - Combined an automatic block signal system with a series of manual interlocking plants.
        - Add a communications system.
        - Gave dispatcher control over train movements.
        - New method of operation by signal indication only.

In 1927, the New York Central installed the first Traffic Control System (TCS).  This system placed a series of remotely controlled manually  interlocking plants within an automatic block territory.  These manual interlocking plants were connected to a central office machine where a single dispatcher could control the entire territory.  The signal system now became the method of train operations.  General Railroad Signal Company installed this system and went on to market it a Centralized Traffic Control (CTC), but CTC is a Traffic control System.

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Traffic Control System Definition

§ 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. 

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A Traffic control system (TCS) is a form of railroad signaling that allows trains to operate on signal indication as their only authority.  TCS consolidates train routing decisions that were previously carried out by local signal operators or the train crews themselves to a single dispatcher in a central office.  One characteristic TCS is a control display graphical depiction of the railroad. On this display the dispatcher can keep track of trains' locations across the territory that the dispatcher controls.  Larger railroads may have multiple dispatcher's offices and even multiple dispatchers for each operating division.   The BNSF, CSX, and Union Pacific all have large centralized dispatching offices.

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Traffic Control System (TCS)
        - A method of operation whereby train movements are authorized by signal indication only.
        - TCS territories are controlled from a central dispatching office via a control console. 
        - Train dispatcher directly controls the position of switches and the display of signal aspects.
        - And on multiple track lines, any track can be used for movements in either direction. 

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Traffic Control System (TCS) is 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. TCS consolidates train routing decisions that were previously carried out by local operators or the train crews themselves. 

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Traffic Control System (cont.)
        - Combined the operating systems and rule of ABS and interlocking systems.
        - Generically referred to as Centralized Traffic Control (CTC).

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The system consists of a centralized train dispatcher's office that controls railroad interlockings and traffic flows in portions of the rail system designated as TCS territory. One hallmark of TCS is a control panel with a graphical depiction of the railroad. On this panel the dispatcher can keep track of trains' locations across the territory that the dispatcher controls. Larger railroads may have multiple dispatcher's offices and even multiple dispatchers for each operating division.

TCS is often generically referred to as Centralized Traffic Control or CTC.

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Traffic Control System

A method of operation whereby train movements are controlled by signal indication only. Signal indications of a TCS system supersede timetable superiority of trains. Usually, signal indications, switch positions, and train location information (track indication) is displayed on the control operator's (or dispatcher’s) visual control equipment. 

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TCS or CTC is a method of train operation whereby train movements are authorized by signal indication only.

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Traffic Control System

Signal indication of a Traffic Control Signal System will be the authority for train movement.

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A TCS system is essentially a series of remotely controlled manual interlocking plants in ABS territory.  For that reason, many of the signal rules and operating rule that apply to interlockings and ABS also apply in a TCS system.

Block Register Territory (BRT)
        - BRT is a designation applied to some lightly used segments of track .
        - In these areas, trains are authorized to move into the territory when a special type of log book is filled out correctly.

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Block register territory (BRT) is a designation applied to some lightly used segments of track. In these areas, trains are only authorized to move into the territory when a special type of log book is filled out correctly. BRT is described in the General Code of Operating Rules (GCOR) as Rule 6.15. 

A standard block register has rows divided into five columns:
          - An identifier for the train, work crew, or other equipment using the line
          - The last name of the employee in charge of the equipment or crew
          - The current date
          - The time at which the track was entered
          - The time at which the track was cleared

The first four columns of the register are filled out upon entering the block. When the track is exited, the last column is filled out and the entire entry is crossed out.

Generally, only one train can occupy block register territory at a time.  Additional trains are only allowed to occupy the block if the operator of the incoming train has contacted all of the other employees named in the open entries in the block register.  Train movements are then made at restricted speed, a low enough speed that the train could stop within half the distance between it and an oncoming train or obstacle.

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        - It is important  that all operating and engineering employees know what systems are in place and which rules apply
        - Refer to Timetables, Special Instructions  and General Orders for more info when necessary
        - Remember - A signal system may be the “method of operation”, (e.g. TCS).
        - Or it may simply be a supplement to the method of operation, (e.g. ABS).

Method Of Operation & Signal Systems

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Automatic Cab Signal System
        - Automatic Cab Signal System will usually be supplemented with train orders or some type of written authority, however the cab signal system is heavily relied upon for safety and keeping trains separated and allows trains to operate at  speeds in excess of 79 MPH.

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An Automatic Cab Signal System (ACS) is a system that allows the signal aspect to be displayed in the cab of the controlling locomotive.  49 CFR 236.0 allows trains equipped with ACS to operate in excess of 79 mph.  ACS is not a method of train operation.

Automatic Train Stop (ATS)

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An Automatic Train Stop System (ATS) is designed to monitor the signal aspects and train speed.  If the train passes a restricting signal and the operator does not reduce the speed of the train to the proscribed speed the system will initiate a full service application of the train air brake syste,

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Automatic Train Control (ATC)

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Automatic train control (ATC) is a general class of train protection that involves a speed control mechanism in response to external inputs. ATC systems tend to integrate various cab signal technologies.  In the case of ATC if an operator passes a restricting signal and does not reduce the train speed the system will automatically make a speed reduce to the required speed or other pre-established speed.

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Signal Systems

-  ACS, ATC & ATS Signal Systems
        - Automatic cab signal, train control and train stop systems are currently installed on many miles of railroad in the U.S. 
        - Today, in most cases, these systems are used as a safety supplement to other methods of operation, e.g. TCS systems, Train Orders, TWC, etc

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ACS, ATC, and ATS, along with new Positive Train Control Systems (PTC) are, in most cases, not methods of train operation.  Rather, they are system overlays to improve the safety and efficiency of train operations.

More InformationRegardingMethods of Train Operation

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Method Of Operation & Signal Systems

OPERATING RULES

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Method Of Operation & Signal Systems

Become familiar with the operating rules for your railroad, especially the “General Signal Rule” section and the “Aspects and Indications” section.

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Timetable & Special Instructions

Become familiar with timetable and general bulletin special instructions.

Special instructions can be very important regarding how train operation interacts with the signal system.

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Timetable & Special Instructions

Special instructions and  notes  regarding interlockings, drawbridges and other special signal arrangements should be legible, accurate and posted at the location, in the timetable or both.

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Become familiar with the various signal aspects and indications used on the railroad.  These will usually be found in the operating rule book or special instructions.

Timetable & Special Instructions

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Timetable & Special Instructions

There are various signal aspects for each railroad. Sometimes there are more than one set of aspects listed for a railroad.

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Timetable & Special Instructions

Aspects and indications govern train movement All S&TC Employees should be familiar with these rules.

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Method Of Operation & Signal Systems

Operating rules, special instructions and general bulletins should also address the safe functioning and operation of signal systems and highway grade crossing warning devices.  For Example:

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Method Of Operation & Signal Systems

Railroads sometime mix various systems and methods of operation which make it difficult for employees to fully understand what systems are in place and what rules regulations may apply.

If in doubt contact your supervisor.

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Methods Of Train Operations and Signal Systems 

The End

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