Office of Research and 

Development 

Washington, DC 20590 

 DOT/FRA/ORD-07/23 October 2007 

 Final Report

This document is available to the

U.S. public through the National

Technical Information Service

Springfield, VA 22161.

Federal Railroad

Administration

U.S. Department

of Transportation

In-Service, Over-the-Road Testing of One 

Car for Tank Car Operating Environment 

Study (Phase IIA) Test Results 
Notice 

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4. TITLE AND SUBTITLE 5. FUNDING NUMBERS 

In-Service, Over-the-Road Testing of One Car for Tank Car 

Operating Environment Study (Phase IIA) Test Results DTFR53-93-C-0001 

6. AUTHOR(S) Task Order No. 208 

Kevin Koch 

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Transportation Technology Center, Inc. REPORT NUMBERS

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This document is available through National Technical 

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13. ABSTRACT

This report documents the procedure and results of the controlled testing conducted during Phase II of a 

tank car operating environment program involving the Association of American Railroads, the Railway 

Supply Institute (formerly Railway Progress Institute), the Federal Railroad Administration, and 

Transport Canada. This investigation is part of an ongoing assessment of what is necessary for a 

complete system optimization (i.e., to assure safety while minimizing total cost). 

The same donated tank car that was used for all of the Phase I testing (with transducers and instrumented 

couplers mounted) was placed in over-the-road service for a period of 6 months. A wireless Internet 

connection utilizing two-way text messaging was the primary system used to monitor the summary data 

from each channel. Relationships between strain gage output and associated forces were established 

before onsite and over-the-road testing began. By the end of the over-the-road test in January 2005, the 

transducers, data acquisition system, and its power supply were operating relatively well. Problems 

remain to be solved, however, before a similar system is installed on a larger number of test cars. 

14. SUBJECT TERMS 15. NUMBER OF 

Transducer package, data acquisition system, data transmittal systems, coupler PAGES 

and body bolster force operating environments 47 

16. PRICE CODE

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF 

OF THIS PAGE OF ABSTRACT ABSTRACT 

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED 

NSN 7540-01-280-5500 Standard Form 298 (Rec. 2-89) 

Prescribed by ANSI/NISO Std. 

239.18 

298-102
ii 
iii 

Table of Contents 

List of Figures............................................................................................................................ v 

List of Tables ............................................................................................................................. v 

Executive Summary................................................................................................................... 1 

 1.0 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Introduction...................................................................................................................... 3 

2.0 Objective and Background............................................................................................... 5 

 2.1 Background–Phase I .............................................................................................. 5 

 2.2 Objective–Phase IIA .............................................................................................. 6 

3.0 Test Procedure–Phase IIA ............................................................................................... 7 

 3.1 Test Car.................................................................................................................. 7 

 3.2 Instrumentation ...................................................................................................... 8 

 3.3 Transducer Calibration ........................................................................................12 

 3.4 On-Track Trail Test–TTC....................................................................................14

 3.5 Extended Over-the-Road Test .............................................................................14 

 3.6 Data Analysis.......................................................................................................16 

4.0 Summary of Results.......................................................................................................17 

 4.1 Transducer Calibration ........................................................................................17 

 4.2 Extended Over-the-Road Test .............................................................................18 

 4.3 Conclusions and Recommendations ....................................................................21 

Appendix..................................................................................................................................25 

Acronyms.................................................................................................................................47 
iv 
v 

List of Figures 

 

 

 

 

 

 

 

 

 

Figure 1. VICX 1725 Test Car.............................................................................................7 

Figure 2. VICX 1725 Test Car–Conduit..............................................................................8 

Figure 3. VICX 1725 Test Car–Storage Box.......................................................................8 

Figure 4. Placement of Strain Gages, Location #21A-22A .................................................9 

Figure 5. Placement of Strain Gages, Location #5 and #6 on Bolster.................................9 

Figure 6. Placement of Gages, Locations #1 and #2 on Bolster........................................10 

Figure 7. Independent Witness Data Acquisition Unit......................................................10 

Figure 8. Bogie Group with Axle Generator Installed.......................................................11 

Figure 9. Typical Force versus Time Curve, Vertical Force Calibration ..........................13 

Figure 10. Vertical Force Application ................................................................................13 

Figure 11. Bolster Load Calibration ....................................................................................14 

List of Tables 

 Table 1. 

 

 

 

 

Primary Transducer Channels.............................................................................11 

Table 2. Vertical Coupler Force versus Gage Output–Upward Force Positive ...............17 

Table 3. Longitudinal Coupler Force versus Gage Output–Tension Positive ..................17 

Table 4. Vertical Force on Bolster versus Strain Gage Output–Casting #2319, A-End ..17 

Table 5. Vertical Force on Bolster versus Strain Gage Output–Casting #2354, B-End...18 
vi 
1 

Executive Summary 

The Association of American Railroads (AAR), the Railway Supply Institute (formerly the 

Railway Progress Institute), the Federal Railroad Administration (FRA), and Transport Canada 

(TC ) are funding a cooperative investigation of the operating environment of tank cars. AAR 

subsidiary Transportation Technology Center, Inc. (TTCI) is conducting this evaluation at the 

FRA’s Transportation Technology Center (TTC), Pueblo, CO. 

Two technical groups are cooperating on this project. One of the groups, known as the Tank Car 

Operating Environment Task Force (TCOE-TF), is evaluating a possible inverse relationship 

between the costs associated with the design/construction of tank cars and handling/operation of 

those cars. The TCOE-TF would like to establish the credibility of a reasonably priced device 

that would collect reliable data that could be used to investigate the frequency and magnitude of 

the largest forces encountered by tank cars during over-the-road service. The second group, the 

Stub Sill Working Group (SSWG), is investigating the use of failure or durability analysis to 

predict the proper inspection interval for stub sill tank cars. SSWG has a need to verify the full 

range of forces that tank cars experience in the railroad operating environment. 

This investigation is part of an ongoing assessment of what is necessary for a complete system 

optimization (i.e., to assure safety while minimizing total cost). Since the research needs are so 

closely related, the two groups have agreed to work together to achieve both objectives. 

This status report describes the procedure and results of the initial tasks of the program’s Phase 

II and the placement of 1 donated tank car (with transducers and instrumented couplers mounted) 

in over-the-road service for a period of 6 months. 

By the end of the over-the-road test in January 2005, the transducers, data acquisition system, 

and its power supply were operating relatively well. Problems remain to be solved, however, 

before a similar system is installed on a larger number of test cars. The recommended solutions 

to these problems can be divided into two categories. The first category would use the system in 

a form very similar to that used in this Phase IIA test. This would be the less costly option. The 

second category would make some significant changes to the structure of the data acquisition 

system. Section 4.3 discusses the following list of recommended solutions in more detail: 

1. Distinct Data Acquisition Systems: In the next phase of this project, two types of data 

acquisition systems should be recognized and applied to different test cars. The objective 

of the first design will be only to monitor significant impact events. In order to meet this 

objective, the data acquisition system will only consist of three accelerometers, plus a 

data recording and storage system. The second data acquisition design would have a 

system sufficiently sophisticated enough to measure coupler and bolster forces at all 

times when car speed is above 5 mph. 

2. Provisions for Electrical Power: The primary problem faced in the Phase IIA test was 

the provision of adequate electrical power for proper operation of the data acquisition 

system. For the second type of data collection system, improvements must be made to 

assure that reliable power is available. 
2 

3. Reporting of System Health: A second problem encountered during the Phase IIA test 

was the lack of consistent reporting on the condition or health of the data acquisition 

system. This inconsistency resulted from the power problems noted previously, as well 

as the erratic nature of cell phone coverage. The most straightforward solution would be 

to use low power satellite phone technology for the primary communication and the 

Internet modem/cell phone connections as a backup. 

4. Reduction of Data Channels: To help lower the power requirements of the data 

acquisition system, it is recommended that the number of channels of data recorded be 

limited to approximately 12. 

5. Onboard Data Processing: In addition to the file reduction steps in Recommendation #4, 

the team recommended that serious consideration be given to the development of a data 

acquisition system that incorporates significant modifications to the design used in Phase 

IIA. 

The option would always be available to retain any and all time domain files with the realization 

that file storage will be filled quicker, and it will likely be impractical to transmit such files from 

the car to a central location in a cost-effective manner using current technology. 
3 

1.0 Introduction 

AAR, RSI, FRA, and TC are funding a cooperative investigation of the operating environment of 

tank cars. AAR subsidiary TTCI is conducting this evaluation at the FRA’s Transportation 

Technology Center (TTC), in Pueblo, CO. 

Two technical groups are cooperating on this project. TCOE-TF is evaluating a possible inverse 

relationship between the costs associated with the design/construction of tank cars and 

handling/operation of those cars. TCOE-TF would like to establish the credibility of a 

reasonably priced device that would collect reliable data that could be used to investigate the 

frequency and magnitude of the largest forces encountered by tank cars during over-the-road 

service. SSWG is investigating the use of failure or durability analysis to predict the proper 

inspection interval for stub sill tank cars. SSWG has a need to verify the full range of forces that 

tank cars experience in the railroad operating environment. 

This investigation is part of an ongoing assessment of what is necessary for a complete system 

optimization (i.e., to assure safety while minimizing total cost). Since the research needs are so 

closely related, the two groups have agreed to work together to achieve both objectives. 

In the fall of 1997, TCOE-TF met to discuss issues and outline a plan of attack. At the meeting, 

topics of discussion included the following: the evolution of freight and tank car design 

standards, a few unique aspects of stub sill railcar designs, the industry’s knowledge to date of 

the operating environment, some railroad ride quality efforts currently in progress, and the 

information contained in accident databases. 

At the conclusion of this meeting, two technical advisory groups (TAGs) were formed to 

undertake further research. The first of these, the cost TAG, was asked to assess costs associated 

with tank car events approaching and exceeding design specifications. The second team, the test 

plan TAG, was asked to develop a methodology for the measurement and reporting of those 

events. As a result of the efforts of the second team, a test methodology comprised of three 

phases was developed. Phase I addressed the development and proof of a methodology to infer 

peak longitudinal and vertical coupler forces from data collected using a relatively inexpensive 

set of transducers. Phase I also included the development of the inexpensive transducer and data 

collection package. Phase I was completed in December 2002. Phase II was designed to provide 

further validation of such a process by subjecting as many as five cars with the minimal 

transducer package to the over-the-road service environment. If Phases I and II were successful, 

Phase III would implement the installation of the inexpensive transducer packages on a large 

number of tank cars to collect environment data. 

This status report describes the procedure and results of the initial tasks of Phase II of the 

program and the placement of 1 donated tank car (with transducers and instrumented couplers 

mounted) in over-the-road service for a period of 6 months. 
4 
5 

2.0 Objective and Background 

2.1 Background–Phase I 

As a portion of Phase I of the Tank Car Operating Environment Program, four car-to-car impact 

sequences have been completed. Brief details of these impact sequences are as follows: 

• Sequence 1–Empty, instrumented tank car was allowed to roll into a stationary 3-car 

anvil string at speeds of 2, 4, 6, and 8 mph. 

• Sequence 2–Loaded, instrumented tank car rolling into stationary 3-car anvil string at 

speeds of 2, 4, 6, and 8 mph. The hand and air brakes were set on the two stationary cars 

farthest from the impact. 

• Sequence 3–Loaded, hopper car rolling into instrumented, stationary tank car at speeds of 

2, 4, 6, and 7 mph. Tank car was not coupled to any other cars. The hand and air brakes 

were set on the stationary tank car. 

• Sequence 4–Loaded, hopper car rolling into instrumented, stationary tank car at speeds of 

2, 4, 6, and 6.5 mph. Tank car was the lead car in a five-car anvil string. The hand and 

air brakes were set on all of the stationary cars. 

Phase I testing also included the controlled application of vertical force pulses to the end of the 

stub sill with the tank car empty, as well as fully loaded. These vertical force application tests 

were conducted in an effort to simulate some of the vertical forces that the stub sill may 

experience during normal in-train operations. The objective of these first tests was to study, 

through controlled testing, the feasibility of estimating or calculating peak longitudinal and 

vertical coupler force using only the recorded output from car-mounted accelerometers or strain 

gages. 

The body of data from the initial testing has shown that definite relationships can be established 

between accelerometer or strain gage output and peak longitudinal and vertical coupler forces. 

The impact data has also shown, however, that while accelerometer output may be able to predict 

the forces due to yard impacts with sufficient accuracy, strain gage and instrumented coupler 

output will most likely be required to produce coupler force data accurate enough to be used for 

fatigue or DTA. The final task of Phase I was to record accelerometer and strain gage response 

during a relatively short-term test that would allow the instrumented tank car to be exposed to an 

operating environment similar to that of standard over-the-road service. Even though data for 

impact severity analysis and environmental data for fatigue or structural durability analysis will 

most likely be supplied by different types of transducer systems (accelerometers versus strain 

gages or instrumented couplers), it was expedient and desirable for this test, as well as for the 

initial portion of Phase II, that both systems remain on a single car. This simulated over-the-road 

test was completed at TTC’s Facility for Accelerated Service Testing (FAST) high tonnage loop. 

Completion of this final task of Phase I met the following objectives: 

• Confirm that relationships between strain gage or accelerometer output and peak coupler 

force can also be established for the lower magnitude coupler forces produced by normal 

train action. The results of the impact tests allowed the study of these relationships for 

peak compressive forces greater than about 250,000 to 300,000 lb. The TAG wanted to 

study the validity of such relationships for both tensile and compressive forces with 

magnitudes from near zero to 250,000 to 300,000 lb. 
6 

• Allow the troubleshooting and development, in a relatively controlled test environment, 

of a data acquisition and storage system that could be operational on the test car for a 

relatively long period of time (4 to 6 weeks). 

• Allow the development of a reliable power generation system (again in a controlled 

environment) that can provide consistent, long-term power for the onboard data 

acquisition hardware while being hidden from casual observation. 

2.2 Objective–Phase IIA 

The tasks of Phase II were designed to build upon the work completed under Phase I by meeting 

the following objectives: 

• Provide for further development of the transducer package, data acquisition system, and 

data transmittal systems. This development will include the design of an installation for 

these systems that will make them relatively invisible to the casual observer on the 

ground. 

• Demonstrate that these systems can reliably provide information on the coupler and body 

bolster force operating environments under long-term standard railroad working 

conditions. Such conditions may include yard impacts, as well as normal over-the-road 

operations. This system will be able to record all of the primary environmental forces 

imposed on a tank car that can produce significant fatigue damage. Phase IIA was not 

designed to produce a complete stand-alone load spectrum for any of the instrumented 

locations. The main objective was to finalize a test design that could eventually 

accomplish that goal. 

• The data transducer and acquisition system used in Phase IIA included rugged but 

relatively inexpensive components that may be used to monitor the existence of severe or 

exceptional impacts, as well as to report the quantity and severity of those events to a 

central location within 48 hours. 

In keeping with the philosophy of proving the viability of concepts before larger scale tasks are 

undertaken and in order to meet funding requirements, Phase II was structured into sub-phases A 

and B. The tasks of Sub-Phase A (Phase IIA) were designed to install the transducer/data 

acquisition/data transmittal system on one donated stub sill tank car. This car was then allowed 

to operate in standard service for approximately 6 months. At the end of this test period, the 

objective was to determine if the body of data collected during the test would allow dynamic 

vertical and longitudinal coupler forces, as well as bolster forces, to be consistently determined 

with acceptable accuracy. This objective also included proof that the system could provide such 

data consistently and reliably. If the objectives of Phase IIA were met, the next tasks of Phase 

IIA could be to install similar systems on at least three additional donated cars. These cars 

should be of common, contemporary designs, significantly different from that of the first car 

tested. 
7 

3.0 Test Procedure–Phase IIA 

3.1 Test Car 

The test car to be used for Phase IIA was the same as that used for all of the Phase I testing. The 

basic specifications are as follows (Figure 1): 

• Manufacturer: American Car and Foundry 

• Car No.: VICX 1725 (Certificate of Construction No. 21826) 

• Empty Weight: 75,400 lb 

• Maximum Weight with Payload of Water: 263,000 lb 

• Tank Design: ACF 4-B-7188, 22,500 Gallon Capacity 

• Underframe Design: ACF 4-B-7190 Stub Sill 

• Coupler Design: 6 1⁄4 x 8 Type E, Top & Bottom Shelf 

• Draft Gear Design: Cardwell Westinghouse Mark 50 All Steel Design (friction wedges 

plus springs) 

• Trucks: Standard Three Piece, Bolster Castings–ASF, AAR-B-2047, 22057-FT, 2-68, 

#2319 (A-End) and #2345 (B-End) 

Figure 1. VICX 1725 Test Car 

Modifications completed on the car to conceal the cabling, transducers, data acquisition, and data 

transmittal systems were as follows: 

• All strain gages and accelerometers concealed by jacketing or fabricated sheet metal 

covers were painted the same color as the test car. 

• All openings in the jacket created to allow the mounting of transducers directly on the 

tank shell were covered with patches. 
8 

• Cabling from transducers to acquisition system concealed within metal conduit were 

painted the same color as the car. 

• Data acquisition and transmittal systems contained within metal boxes were designed to 

blend with the existing structural details. 

• A power generation system is located between the side frames of one of the bogies. 

Section 3.2 describes this system in more detail. 

The test car was loaded with water and weighed before testing began. The total weight of the car 

was measured at 263,350 lb, 130,700 lb on the A-end, and 132,650 lb on the B-end. 

Figure 2. VICX 1725 Test Car–Conduit Figure 3. VICX 1725 Test Car– 

Storage Box 

3.2 Instrumentation 

3.2.1 Transducers 

During the over-the-road testing, output in g’s was recorded from the four individual 

accelerometers listed below. Microstrain output was also recorded from strain gages mounted on 

both bolsters and the stub sills as listed below. Refer to the Appendix for accelerometer and 

strain gage locations. 

• Two longitudinal accelerometers at location #6 

• Two vertical accelerometers at location #6 

• Strain gages at locations: #21-22 (locations #21-22 are typical of both ends of the car) 

• Strain gages on both of the bolsters, as shown in Figure A-3 in the Appendix 

• Instrumented Miner Dyno Coupler designed to measure longitudinal force at each end of 

the car 

One set of accelerometers installed independently on a common block were 100 g units 

manufactured by Endevco. The mounting block for these accelerometers was attached to the car 

structure by welds. The remaining accelerometers were 60 g units contained within a PS-100 

self-contained event recorder supplied by Independent Witness (IW) of Salt Lake City, UT. This 

unit, with the capability to record and store event counts, peak values, and time domain wave 

forms, was mounted using its own bracket welded to the tank structure. 
9 

The strain gages at locations #21A-22A (#21B-22B on B-end of car) were Hitec shear gages 

wired into a half-bridge circuit so that response is sensitive to vertical shear force in the stub sill 

but relatively insensitive to axial forces or bending moments. The output from these gages was 

used to determine vertical coupler force. These gages were mounted on the neutral axis of the 

sill and located between the front draft lugs and the yoke support plate. 

The strain gages at locations #1 and #2 on the bolster were single element gages wired into a 

half-bridge circuit to measure side bearing forces on one end of the bolster. The gages at bolster 

locations #3 and #4 were connected in a similar manner to measure side bearing forces on the 

opposite end of the bolster. Two gages at locations #5 and #6 on the bolster were wired into a 

half-bridge configuration to measure center bowl load. 

Redundant strain gages were mounted at all noted locations. These gages only served as backup 

transducers in the event that problems occurred with the primary units. Figures 4 through 6 

further illustrate strain gage placement. 

An onboard global positioning system (GPS) supplied car velocity data. In addition to car 

position, this system provides vehicle speed data with a resolution of at least .5 mph for speeds 

over 2 mph. 

 Figure 4. Placement of Strain Gages, 

 Locations #21A-22A 

 Figure 5. Placement of Strain Gages, 

 Locations #5 and #6 on Bolster 
10 

 Figure 6. Placement of Strain Gages, 

 Locations #1 and #2 on Bolster 

 Figure 7. Independent Witness 

 Data Acquisition Unit 

3.2.2 Data Acquisition System 

A single TTCI unattended data acquisition system (UDAQ) capable of storing at least 32 

channels of data was mounted on the test car, contained in the box shown in Figure 3. Table 1 

shows the channel listing. The data from the Independent Witness PS-100 unit was sampled at a 

rate of 1800 Hz and filtered at 180 Hz to prevent aliasing. The sampling and filtering capability 

is contained within the PS-100 box. All of the remaining data was sampled at a rate of 1024 Hz 

and filtered at 120 Hz. The strain gage and coupler force data was decimated at 256 Hz to 

maximize data storage space. Response versus time (time series) data recorded during the 

duration of the test was stored on the UDAQ system. When possible, the following data were 

viewed twice daily via a wireless Internet and cell phone connection to monitor system health: 

battery voltage; charge amperage; GPS location and speed; and maximum, minimum, mean, and 

standard deviation values for each data channel. The download of this data was to be automatic. 

Gel cell batteries charged by an axle driven alternator were used to provide long-term electrical 

power for the transducers and the UDAQ. The charging system uses urethane rollers contacting 

the axle to transmit torque through a chain to an automotive alternator. Anytime the car is in 

motion the alternator would normally supply charging current to 2 gel cell 12 volt, 200 amp-hour 

storage batteries. This system was tested during initial shakedown runs at TTCI before the car 

was sent over the road. This system was designed so that it could be partially hidden behind the 

wheels and side frame when viewed from the side of the car. Figure 8 shows that the alternator 

is mounted on the bogie set. 
11 

Figure 8. Bogie Group with Axle Generator Installed 

3.2.3 Data Download System 

The primary system to monitor the summary data from each channel employed a wireless 

Internet connection utilizing two-way text messaging. Download could be performed anywhere 

cell phone service or an active connection to the Internet exists. Communication was completed 

through remote host protocol. An auxiliary monitoring system utilized an onboard satellite 

telephone connected to the UDAQ computer via a serial cable. The phone utilized a selftracking, gyro-controlled antenna to maintain consistent contact with the required satellite. 

Table 1. Primary Transducer Channels 

Channel 

Number Transducer 

1 Car Velocity 

2 Instrumented Coupler A-End 

3 Instrumented Coupler B-End 

4 Strain Gages at Locations #21A-22A (A-End Vertical Coupler Force) 

5 Strain Gages at Locations #21B-22B (B-End Vertical Coupler Force) 

6 Strain Gages #1 & #2 (A-End Bolster Side Bearing Load) 

7 Strain Gages #3 & #4 (A-End Bolster Side Bearing Load) 

8 Strain Gages #5 & #6 (A-End Bolster Center Bowl Load) 

9 Strain Gages #1 & #2 (B-End Bolster Side Bearing Load) 

10 Strain Gages #3 & #4 (B-End Bolster Side Bearing Load) 

11 Strain Gages #5 & #6 (B-End Bolster Center Bowl Load) 

12 Vertical, 100 g Accelerometer at Location #6 (6V) 

13 Longitudinal, 100 g Accelerometer at Location #6 (6L) 

14 thru 23 Spare Instrumented Coupler and Strain Gage Circuits Measuring Vertical 

Coupler Forces and Bolster Forces 

24 Battery Voltage 
12 

3.3 Transducer Calibration 

Before onsite and over-the-road testing began, the relationships between strain gage output and 

associated forces were established using the following procedure:

• With instrumented couplers in place on both ends of the car, quasi-static buff and draft 

loads of up to 250,000 lb were applied while output from gages 21A/22A and 21B/22B 

were recorded. A calibrated load cell was also installed to confirm the output of the 

instrumented couplers. 

• The output from gages #21A/22A and #21B/22B was used as the primary indicator of 

vertical coupler force. Output from these gages was recorded during the application of 

dynamic, as well as static loads to the end of the sill. Initially a hydraulic cylinder was 

used to apply static vertical loads through a calibrated load cell to the end of the sill. 

These tests were conducted with the car loaded, and the vertical forces applied were 

increased slowly from zero to approximately 50,000 lb upward and zero to 20,000 lb 

downward. Each static loading test was repeated at least three times. In addition to the 

static forces, dynamic force pulses of increasing amplitude were applied in the upward 

direction to the end of the sill. Two force pulse sequences were completed. One applied 

the force from zero to approximately 25,000 lb and the other from zero to 50,000 lb. The 

half duration of the pulse, t/2, will be approximately 0.5 second (see Figure 8). Each 

amplitude value was repeated at least three times. Figure 9 shows the configuration for 

the vertical load application. 

• The results of the longitudinal and vertical load tests were used to establish relationships 

that can be used to calculate vertical coupler forces at both ends of the car using the 

output from gages 21A/22A and 21B/22B and the instrumented couplers as variables. 

• The calibration of the bolster gages, 1 through 6, was accomplished by applying static 

forces (through calibrated load cells) in the following sequence: 

1. Apply load to center bowl only (at bowl center and at bowl edges 

independently). 

2. Apply load to one side bearing location only. 

3. Apply load to opposite side bearing location only. 

4. Apply load to each bowl edge and the corresponding side bearing 

simultaneously. 

• Using a hydraulic load frame, the forces were applied slowly from zero to approximately 

100,000 lb. These load sequences were repeated at least three times at each location. As 

with the coupler forces, relationships were established that can be used to calculate center 

bowl and side bearing forces using the output from gages 1 through 6. Figure 10 shows 

the bolster loading configuration. 
13 

Figure 9. Typical Force versus Time Curve, 

Vertical Force Calibration 

Figure 10. Vertical Force Application 
14 

Figure 11. Bolster Load Calibration 

3.4 On-Track Trail Test–TTC 

After the calibration tasks were completed and the test car/instrumentation package fully 

assembled, it was placed in a consist and tested on the rails at TTC. This provided an 

opportunity to demonstrate that all systems on the car were working properly before it departed 

for the over-the-road tests. The test car was placed in a consist with 3 other cars and operated 

over the TTC Railroad Test Track and Perturbed Test Track at speeds of up to 50 mph. Results 

from this test demonstrated that all channels were recording data properly, batteries were being 

charged as designed, and no apparent problems existed with the axle driven alternator 

installation. During this trial, test data was recorded and downloaded from all channels. During 

these trial tests the VICX1725 car was loaded as shown in Section 3.1. 

3.5 Extended Over-the-Road Test 

During the Phase IIA test the car was scheduled to follow the route detailed below: 

Burlington Northern Santa Fe Railroad Section of Route 

Pueblo, CO 

LaJunta, CO 

Amarillo, TX 

Lubbock, TX 

Sweetwater, TX 

Temple, TX 

Houston, TX 

Lafayette, LA 

LaJunta, CO 

Amarillo, TX 

Lubbock, TX 

Sweetwater, TX 

Temple, TX 

Houston, TX 

Lafayette, LA 

New Orleans, LA 
15 

CN Section of Route 

New Orleans, LA Chicago, IL 

NS Section of Route 

Chicago, IL 

Bellevue, OH 

Conway, PA 

Allentown, PA 

Harrisburg, PA 

Roanoke, VA 

Knoxville, TN 

Chattanooga, TN 

Birmingham, AL 

Meridian, MS 

Bellevue, OH 

Conway, PA 

Allentown, PA 

Harrisburg, PA 

Roanoke, VA 

Knoxville, TN 

Chattanooga, TN 

Birmingham, AL 

Meridian, MS 

New Orleans, LA 

The New Orleans to Harrisburg to New Orleans loop would be traveled at least twice. The total 

distance accumulated for the segment from Pueblo to New Orleans, 2 loops from New Orleans to 

Harrisburg and back to New Orleans and the return trip from New Orleans to Pueblo, was 

estimated to be approximately 8,700 miles. The following key points applied to this over-theroad test: 

• The car was placed in standard trains and retained all of the original labeling and 

stenciling. The test car was loaded with water and had water placards installed. The car 

was weighed on the TTC scales before testing began. The measured weight of the car 

was 263,350 lb as shown in Section 3.1. 

• Data recording began when the car left Pueblo en route to Houston. 

• Basic system health and GPS were monitored daily via a wireless Internet connection 

when connections were adequate. The following data was reported and inspected during 

these checks: battery voltage; charge amperage; GPS location and speed; and maximum, 

minimum, mean, and standard deviation values for each data channel. 

• Strain and coupler force data were recorded continuously while the car was traveling 

above 5 mph (see Section 3.6). This time domain data from the first 2 to 3 days of travel 

would be downloaded in its entirety using the satellite phone connection. This would be 

a test of the practicality of such data download procedures. As the test progressed, 

however, continuing concerns with adequate onboard electrical power and the time 

required to download a full set of data resulted in an abandonment of this portion of the 

test. Section 4.2 gives further detail. The complete download of data collected occurred 

only when TTCI personnel visited the car. 

• TTCI engineering and instrumentation personnel planned to travel to the car to download 

data and inspect the systems at least two times during the test’s duration. Eventually 

problems with the maintenance of adequate onboard power resulted in a requirement that 

TTCI personnel visit the car more than twice. Section 4.2.1 gives details. 
16 

• Mileage would also be accumulated with the car empty if time allowed. As the test 

progressed and electrical power problems persisted, however, the focus had to be 

concentrated on the accumulation of sufficient, valid data with the car loaded. 

3.6 Data Analysis 

Data from the strain gages and instrumented couplers was to be recorded continuously while the 

car was traveling at a speed of more than 5 mph. At a speed of less than 5 mph, this data was 

recorded and stored only when vertical coupler force at either end of the car exceeded 10,000 lb, 

longitudinal coupler force at either end of the car exceeded 25,000 lb, or vertical or longitudinal 

acceleration exceeded 2.5 g. The Independent Witness unit recorded and stored acceleration 

versus time data only when vertical or longitudinal acceleration exceeded 2.5 g. Notification of 

the occurrence of events and the severity (maximum acceleration value in each axis), however, 

was recorded if longitudinal or vertical acceleration exceeded plus or minus 0.5 g. The 

Independent Witness unit recorded such data regardless of whether the car was moving or 

stationary. Activation of the unit at speeds less than 5 mph resulted in data being recorded for a 

duration of 4 to 5 seconds, beginning 0.5 seconds before the time of the triggering event. If a 

threshold value remained in place for a long period of time (more than 10 seconds), the system 

ceased recording. Acceleration and strain data was used to determine the following: 

• The full spectrum of the vertical and longitudinal coupler force environment at each end 

of the car. This data was processed as time-dependent traces and as rainflow cyclecounted, range-mean histograms. 

• The full spectrum of the bolster center bowl and side bearing loads. These were also the 

loads applied to the body bolsters. This data was also processed as time dependent traces 

and as rainflow-counted, range-mean histograms. 

• The level of agreement of the peak acceleration values recorded by the individual 100 g 

accelerometers with those recorded by the Independent Witness PS100 unit. Such a 

comparison was made on the basis of the peak values of individual events. The reason 

for this comparison was to evaluate the Independent Witness transducers against the 

values produced by the known performance of the Endevco units. Good correlation 

between the two transducers, especially at larger acceleration levels, would provide some 

level of confidence that the Independent Witness units could be used as stand-alone 

transducers on future systems. 

• The full spectrum of longitudinal acceleration values above 2.5 g were measured by the 

TTCI-installed and Independent Witness accelerometers. This included time histories 

and histogram summaries. Similar data was also available from the vertical 

accelerometers when longitudinal acceleration is greater than 2.5 g. 
17 

4.0 Summary of Results 

4.1 Transducer Calibration 

4.1.1 Strain Gages to Measure Vertical Coupler Force 

The following tables list sensitivities of the strain gages mounted on the stub sills and designed 

to measure vertical coupler force. 

Table 2. Vertical Coupler Force versus Gage Output–Upward Force Positive 

Load Direction A-End Primary 

Gages Kip/Volt 

A-End Backup 

Gages Kip/Volt 

B-End Primary 

Gages Kip/Volt 

B-End Backup 

Gages Kip/Volt 

Upward 12.9 13.2 13.1 13.8

Downward 13.1 13.2 12.7 13.0

Table 3. Longitudinal Coupler Force versus Gage Output–Tension Positive 

Load Direction A-End Primary 

Gages Kip/Volt 

A-End Backup 

Gages Kip/Volt 

B-End Primary 

Gages Kip/Volt 

B-End Backup 

Gages Kip/Volt 

Compression -563.8 -655.3 -112.7 -116.3 

Tension -426.8 -534.4 -289.9 -160.3 

4.1.2 Strain Gages to Measure Bolster Center Bowl and Side Bearing Loads 

Tables 4 and 5 list sensitivities of the strain gages mounted on the bolsters, designed to measure 

center bowl and side bearing force. The sensitivity constants shown in Tables 2 and 3 were used 

to produce equations that could be used to convert voltage output from strain gages to vertical 

coupler force. In the same way, the sensitivity constants shown in Tables 4 and 5 were used to 

produce equations that could be used to convert voltage output from strain gages to bolster 

center bowl and side bearing force. All output voltage versus force relationships were 

essentially linear. 

Table 4. Vertical Force on Bolster versus Strain Gage Output–Casting #2319, A-End 

Bottom of Bottom of Side Side Side Side 

Bolster Bolster Bearing Bearing Bearing Bearing 

Load Type Primary Backup #1/2 #1/2 #3/4 #3/4 

Gages Gages Primary Backup Primary Backup 

Kip/Volt Kip/Volt Kip/Volt Kip/Volt Kip/Volt Kip/Volt 

Center Bowl 45.0 45.2 185.2 210.5 231.4 250.1

Side Bearing 

Above 21.9 22.9 133.1 137.3 651.6 717.4

Location 1/2 

Side Bearing 

Above 574.7 680.7 138.2 139.2 25.0 24.9

Location 3/4 
18 

Table 5. Vertical Force on Bolster versus Strain Gage Output–Casting #2354, B-End 

Bottom of Bottom of Side Side Side Side 

Bolster Bolster Bearing Bearing Bearing Bearing 

Load Type Primary Backup #1/2 #1/2 #3/4 #3/4 

Gages Gages Primary Backup Primary Backup 

Kip/Volt Kip/Volt Kip/Volt Kip/Volt Kip/Volt Kip/Volt 

Center Bowl 43.3 43.8 186.5 205.5 217.1 194.6

Side Bearing 

Above 21.1 23.2 151.3 149.4 949.7 738.9

Location 1/2 

Side Bearing 

Above 558.6 665.3 137.6 136.4 22.8 24.0

Location 3/4 

4.2 Extended Over-the-Road Test 

4.2.1 Trip Summary 

The over-the-road testing portion of this program began July 10, 2004. Except for a segment of 

time between September 28 and November 17, 2004, the car was on railroads between Pueblo 

and the eastern United States until January 26, 2005. The car accumulated approximately 15,000 

miles during the 6-month duration of the test. Because of data acquisition problems that are 

detailed below, approximately 220 hours of data was accumulated, covering about 6,800 miles of 

travel. The accumulated file size for all of the data collected was approximately 40 gigabytes 

(GB). The following gives a brief chronological summary of the 6 months of testing. 

• Car traveled to New Orleans, LA, via Amarillo, Lubbock, and Houston, TX. All systems 

operated properly through July 13, 2004, when the car arrived in Lubbock. Two attempts 

were made to download files (about 2.0 GB) recorded on July 10-11, 2004, via satellite 

phone. The process to list the files before the transmission consumed over 2 hours, 

which exceeded the preset time limit for the phone to be activated. After July 13, 2004, 

as the car traveled on to New Orleans, LA, daily contact was lost, and no further attempts 

were made to download full-time domain data files. 

• Team from TTCI traveled to New Orleans, LA, on July 22, 2004, to determine why 

contact with the car was lost. The team found that the battery voltage was too low. 

Diagnosis was that much of the time train speed was too low for the alternator to 

adequately charge the batteries. A different alternator was installed that would provide 

adequate charging amperage at lower travel speeds. All other systems appeared as they 

should. 

• Between July 27 and August 20, 2004, the car traveled to Chicago, IL, and on to 

Harrisburg, PA. No further attempts were made to download large time domain files via 

satellite phone due to concerns of adequate battery voltage. All systems appeared to 

operate properly until about August 10, 2004. After that date contact was lost. A team 

from TTCI again visited the car in Harrisburg. The team discovered that one of the drive 

chains used to power the alternator had been damaged and broken. The chain was 

replaced. All other components of the data acquisition system appeared in good 

condition. 
19 

• Between August 21 and August 28, 2004, the car remained essentially stationary in 

Harrisburg. It finally left Harrisburg on August 29, 2004, and arrived in New Orleans on 

September 6, 2004. Contact was lost before the car left Harrisburg. The team speculated 

that the battery voltage dropped below the adequate operational level while the car was 

stationary, and the alternator was never able to bring the voltage back to the proper value. 

After the car arrived in New Orleans, the decision was made to bring it back to Pueblo, 

CO, for modifications to the charging system circuits. Between September 13 and 

September 28, 2004, the car traveled back to Pueblo. 

• Between September 28 and November 17, 2004, the car remained in Pueblo for charging 

circuit modifications and installing an enhanced Independent Witness system that would 

allow acceleration events and car location to be constantly monitored on the Independent 

Witness Web site. 

• Between November 17 and December 6, 2004, the car traveled from Pueblo to Chicago 

to Roanoke, VA, and then to New Orleans. Even though contact was sporadic due to cell 

phone service, all systems appeared to be operating properly; the team decided to send 

the car for one more loop to Chicago, Roanoke, and back to New Orleans. 

• Between December 7, 2004, and January 6, 2005, the car traveled from New Orleans to 

Chicago to Roanoke and back to New Orleans. After the car arrived in Chicago on 

December 12, 2004, daily contact was lost and not regained. 

• When the car arrived in New Orleans, a TTCI technician traveled to meet it, downloaded 

data from the data acquisition system, and determined the reason for loss of contact. 

Instrumentation technicians discovered that one of the axle-to-alternator drive chains had 

again broken, allowing the battery charge to decrease to a level under that which the 

acquisition system could not operate. 

• Between January 13 and January 26, 2005, the car traveled from New Orleans to Chicago 

and back to Pueblo. Contact was maintained through this section of the test, and all 

systems appeared to operate properly. 

4.2.2 Data Summary 

Approximately 62 percent (covering 27 days) of the 220 hours of data collected during the Phase 

IIA test has been analyzed in detail. This data analysis includes the following trip segments: 

• July 12 to July 15, 2004–Pueblo, CO, to Lubbock, TX 

• July 27 to August 2, 2004–New Orleans, LA, to Chicago, IL, to Harrisburg, PA 

• November 16 to December 7, 2004–Pueblo, CO, to Chicago, IL, to Roanoke, VA 

In addition to the 5,000 files inspected and analyzed in detail, basic statistics, such as maximum, 

minimum, and mean values, were tabulated for ten 98-second data files recorded during the last 

days of the test (January 19-26, 2005). These statistics were compared to those of 10 files 

previously analyzed in detail and found to be very similar in value and character. The close 

agreement of the statistics for the two groups of files provided confidence that the quality of data 

contained in the files not yet analyzed in detail was equivalent to the data in the files recorded 

between July 10 and December 7, 2004. Since the primary objective of this test was to 

demonstrate that quality environmental data could be recorded and stored over a relatively long 

period of time, it did not seem an efficient use of the remaining project resources to analyze 100 

percent of the data in detail at this time. Figures A-10 through A-27 in the Appendix illustrate 
20 

the type of summary analysis completed and the range-mean histograms created for the data 

recorded through December 7, 2004. Similar histograms files could be created for the remainder 

of data recorded from December 8, 2004, through January26, 2005, if it is eventually thought to 

be worthwhile. 

All channels except one of the B-end bolster side bearing circuits (Channel 10) recorded data 

without significant problem. This channel began to record values that were unrealistically low, 

indicating that the bond between one of the gages and the steel surface could have been partially 

lost. Data from the backup circuit was used to supplement that from Channel 10. Data was 

processed and summarized to produce the following for each day and for the total body of data 

accumulated: 

• Absolute maximum and minimum values for each channel as applicable. 

• Maximum ranges from rainflow cycle-counted, range-mean histograms. 

• Number of ranges above certain thresholds also derived from the rainflow cycle-counted, 

range-mean histograms. 

• Comparison of accelerometer response between TTCI-installed units and the Independent 

Witness units. 

Tables A-1 through A-4 in the Appendix show the absolute maximum and minimum values, as 

well as the maximum ranges, recorded for each channel for the data analyzed in detail. Tables 

A-5 through A-8 show a summary of the longitudinal coupler, vertical coupler, bolster center 

bowl, and bolster side bearing load ranges above arbitrarily chosen levels recorded for all of the 

data analyzed in detail (July 10 through December 5, 2004). This kind of summary indicates the 

relative severity of the route, as well as a comparison of the severity of the forces at each end of 

the car. Several observations of interest include the following: 

• Both longitudinal and vertical coupler forces at the B-end of the car were somewhat 

higher than those at the A-end. This was especially significant for the vertical forces. 

This trend is indicated by the peak values, as well as the number of load range cycles 

above specific levels. The test car received an extensive post-test inspection when it 

returned to TTC in January 2005. This inspection revealed 2 pieces of evidence that 

strongly indicate that the differences in recorded vertical coupler forces between the Aand B-ends were accurate: (1) with each coupler shank resting on the bottom of the stub 

sill, opening the distance between the top of the shank and the top striker was 1 3/8 inch 

on the A-end but only 1 1/16 inch on the B-end; (2) there was evidence on the B-end 

coupler shank that it had contacted the top striker on the stub sill several times with 

considerable force. No clear evidence of such heavy contact on the A-end existed. 

• The vertical center bowl load spectrums on each bolster appear to be comparable. For 

each bolster, the maximum dynamic vertical force is approximately 2.2 to 2.6 times the 

static load. 

• The vertical load spectrum on the bolster side bearings appears to be relatively similar for 

all locations except that represented by the data of Channel 7. As Table A-8 shows, the 

load ranges above 20,000 lb and 40,000 lb on the Channel 7 side bearing were 3 to 5 

times higher than for any other side bearing. The side bearing clearance gaps at all 4 

locations were relatively consistent at 1/4 to 5/16 inch. Therefore side bearing settings 

do not appear to have contributed to this difference in load spectrum. It is also possible, 
21 

however, that on a used car the variation in spring or damping rates at this corner of the 

car could have contributed to the differences. 

• As Table A-9 shows, some significant differences exist between the Independent Witness 

peak accelerometer readings and those of the Endevco units installed by TTCI. This is 

especially true at the lower acceleration levels. When viewing this data, however, several 

factors must be considered. The Endevco accelerometers had the capability to measure 

100 g’s full scale. Therefore, the resolution of these units at 2 to 3 g’s or 2 to 3 percent 

of full scale is not that good. The Independent Witness accelerometers were of 60 g fullscale capability, providing somewhat better resolution at low acceleration levels. 

Another interesting observation made from inspection of the force range data was that some 

sections of the route produced relatively high forces more often than others: 

• Longitudinal and vertical coupler forces occurred more often on an event per hour basis 

during the July 28-30, 2004, timeframe when the car was traveling from New Orleans to 

Chicago. 

• Relatively high bolster forces occurred more often by a significant amount on November 

18, 2004, when the car was traveling from Pueblo to Chicago. This is an indication of 

relatively consistent significant pitch or bounce motion. 

• Relatively high side bearing forces occurred more often on July 10, 2004, when the car 

was traveling from Pueblo to Lubbock. This is an indication of relatively consistent 

significant roll motion. 

Figures A-4 through A-7 in the Appendix show some time versus force data for typical high load 

events. Figures A-10 through A-30 show rainflow cycle-counted, range-mean histograms for 3 

days for which the data has been analyzed in detail. 

Some effort was made to investigate the level of correlation between longitudinal and vertical 

coupler forces at any particular step in time. The team determined that even though occasions 

exist when a noticeable relationship exists between longitudinal and vertical coupler force levels, 

any correlation is not consistent or exact enough to be used as a tool in the computation of stress 

levels within the structure. Figures A-8 and A-9 show an example of this. Figure A-8 shows 

that during this 2,000 seconds of data, the longitudinal and vertical forces follow similar trends, 

but a cross plot of the same data shows considerable scatter when the values from 1 channel are 

plotted against those of the other. 

4.3 Conclusions and Recommendations 

By the end of the over-the-road test in January 2005, the transducers, data acquisition system, 

and its power supply were operating relatively well. The signal was lost from the B-end 

instrumented coupler at some point when the car was traveling back to Pueblo in January 2005. 

It appears, however, that a person must have disconnected a coupler for the primary data cable, 

resulting in loss of signal. This coupler was located between the knuckle and the end of the stub 

sill. Problems remain to be solved, however, before a similar system is installed on a larger 

number of test cars. The recommended solutions to these problems can be divided into two 

categories. The first category would use the system in a form very similar to that used in this 

Phase IIA test. This would be the less costly option. The second category would make some 
22 

significant changes to the structure of the data acquisition system. The following lists these 

problems and possible solutions in the recommendations below: 

1. Distinct Data Acquisition Systems: In the next phase of this project, two types of data 

acquisition systems should be recognized and applied to different test cars. The objective 

of the first design will be only to monitor significant impact events. In order to meet this 

objective, the data acquisition system will only consist of three accelerometers, plus a 

data recording and storage system. The least complicated option for such a system would 

be powered by small long-lasting batteries and would require a periodic manual data 

download. A more costly option would transmit location and event data via a low power 

satellite phone connection to a central location that would process the data so that it could 

be displayed on an Internet Web site. This system would require larger batteries that 

could be adequately charged with a small solar cell. Both systems would record data 

only when acceleration levels exceeded relatively high predetermined levels. The 

technology for both systems is currently available from Independent Witness 

Incorporated in Salt Lake City, UT. The second type of car would have a data 

acquisition system sufficiently sophisticated to measure coupler and bolster forces at all 

times when car speed is above 5 mph. The data supplied by this type of option would be 

used for fatigue or crack growth analysis. The following addresses the second type of 

system. 

2. Provisions for Electrical Power: The primary problem faced in the Phase IIA test was 

the provision of adequate electrical power for proper operation of the data acquisition 

system. For the second type of data collection system, improvements must be made to 

assure that reliable power is available. Even though most components of the electrical 

system were working adequately at the end of the Phase IIA test, the problem of 

alternator drive chain breakage has not been totally solved. The solution to this problem 

could take two forms. The most straightforward and least expensive solution could be to 

drive the alternator with a cogged belt instead of a chain. This would eliminate the 

problems associated with misalignment and lack of lubrication. A guard should also be 

provided to protect the belt from flying debris. The following gives a more 

comprehensive proposal to lessen the problems associated with providing electrical 

power. 

3. Reporting of System Health: A second problem encountered during the Phase IIA test 

was the lack of consistent reporting on the condition or health of the data acquisition 

system. This inconsistency was due to the power problems noted previously, as well as 

the erratic nature of cell phone coverage. The most straightforward solution would be to 

use low power satellite phone technology for the primary communication and the Internet 

modem/cell phone connections as a backup. 

4. Reduction of Data Channels: To help lower the power requirements of the data 

acquisition system, it is recommended that the number of channels of data recorded be 

limited to approximately 12: coupler forces at each end, center bowl and side bearing 

forces for each bolster, car speed, and battery voltage. Backup transducers could be 

installed; but if a primary unit fails the secondary unit would have to be brought online 
23 

manually. With this reduction of channels, however, it is still anticipated that a battery 

charging system other than solar cells would be required. The team recommended that 

the sample rate for all channels be reduced to a maximum of 256 samples per second. 

With the reduction of channels and the sample rate, the current UDAQ system could store 

up to 7 to 8 months of data before a download would be required. 

5. Onboard Data Processing: In addition to the file reduction steps in Recommendation #4, 

the team recommended that serious consideration be given to the development of a data 

acquisition system that incorporates significant modifications to the design used in Phase 

IIA. This system could be developed with the assistance of Independent Witness 

Incorporated using some of their storage and reporting technology. Some of the features 

would be as follows: 

• Lower power requirements than the UDAQ system, using smaller batteries and 

possibly one small solar cell for recharging the batteries. 

• Up to 12 channels recording data at 256 samples per second. 

• Newly developed software that would internally monitor all channels for health 

by basic statistical analysis. If a channel is deemed healthy, the software would 

convert the time domain files to cycle counted histograms using one or two of 

several available methods. An option would then be available to overwrite the 

time domain files, saving file storage space and power consumption. The 

statistical data files and histograms files, significantly smaller than time domain 

files, could be transmitted to a central site via low power satellite phone 

communications. 

• The option could be available to access channel statistics and histogram data via 

an Internet site maintained by Independent Witness. 

The option would always be available to retain any and all time domain files with the realization 

that file storage will be filled quicker, and it will likely be impractical to transmit such files from 

the car to a central location in a cost-effective manner using current technology. 
24 
25 

Appendix. 

Accelerometer and Strain Gage Locations 

 

66

Figure A-1. Accelerometer Locations 
26 

Figure A-2. Strain Gage Locations Measuring Vertical Force–Stub Sill 

The lateral dimensions reference the edge of the underframe. 

The longitudinal dimensions reference the front of the 

front pilot plate. 

21,(22 on

other side on

neutral axis)

21,(22 on

other side on

neutral axis)

Rear

Draft 

Lugs

21 (22 on other 

side of neutral 

axis) 
27 

Figure A-3. Strain Gage Locations–Bolsters 

 

5 & 6 

1 & 2 3 & 4 
28 

SUMMARY OF DATA 

Table A-1. Maximum/Minimum Peak Values and Ranges–Longitudinal Coupler Forces 

 Date Location A-End A-End A-End B-End B-End 

Maximum Minimum Maximum Maximum Minimum 

(lb) (lb) Range (lb) (lb) 

(lb) 

July 30 New Orleans to Chicago 413,200 563,740 

November 18 Pueblo to Chicago -128,440 -277,070 

July 31 New Orleans to Chicago 682,150 

Table A-2. Maximum/Minimum Peak Values and Ranges–Vertical Coupler Forces 

 Date Location A-End A-End A-End B-End B-End 

Maximum Minimum Maximum Maximum Minimum 

(lb) (lb) Range (lb) (lb) 

(lb) 

November 28 Chicago to Roanoke 55,480 75,970 

November 19 Pueblo to Chicago -29,530 

July 14 Pueblo to New Orleans 291,600 

November 21 Pueblo to Chicago -100,780 
29 

Table A-3. Maximum Peak Values and Ranges–A-End Bolster 

Date Location 

Center Bowl 

Maximum 

(lb) 

Center Bowl 

Maximum 

Range 

(lb) 

Channel 6 

Side Bearing 

Maximum 

(lb) 

Channel 6 

Side Bearing 

Maximum 

Range 

(lb) 

Channel 7 

Side Bearin

Maximum 

(lb) 

July 29 New Orleans to Chicago 232,900 195,610 July 10 Pueblo to New Orleans 105,000 105,000 121,010 

Nominal or average load on bolster approximately 104,000 lb 

Table A-4. Maximum Peak Values and Ranges–B-End Bolster 

Date Location 

Center Bowl 

Maximum 

(lb) 

Center Bowl 

Maximum 

Range 

(lb) 

Channel 9 

Side Bearing 

Maximum 

(lb) 

Channel 9 

Side Bearing 

Maximum 

Range 

(lb) 

Channel 10 

Side Bearin

Maximum 

(lb) 

July 29 New Orleans to Chicago 282,950 262,020 July 10 Pueblo to New Orleans 90,340 90,300 

December 2 Chicago to Roanoke 68,480 Nominal or average load on bolster approximately 108,000 lb 
30 

Table A-5. Load Range Summary–Longitudinal Coupler Force 

Number of Load Range Cycles 

Above 150,000 lb 

Number of Load Range 

Cycles Above 200,000 lb 

A-End Coupler 426 219 

B-End Coupler 654 381 

Table A-6. Load Range Summary–Vertical Coupler Force 

Number of Load Range Cycles 

Above 25,000 lb 

Number of Load Range 

Cycles Above 50,000 lb 

A-End Coupler 319 18 

B-End Coupler 3,323 767 

Table A-7. Load Range Summary–Bolster Center Bowl Load 

Number of Load Range Cycles Number of Load Range Cycles Number of Load Ra

Above 25,000 lb Above 50,000 lb Above 100,0

A-End Coupler 44,340 4,022 75 

B-End Coupler 52,945 5,170 154 
31 

Table A-8. Load Range Summary–Bolster Side Bearing Loads 

Number of Load Range Cycles Above Number of Load Range Cycles 

20,000 lb 40,000 lb 

A-End Bolster, Channel 6 Side Bearing 137 18 A-End Bolster, Channel 7 Side Bearing 458 136 

B-End Bolster, Channel 9 Side Bearing 121 26 A-End Bolster, Channel 6 Side Bearing 196 26 

Table A-9. Comparison of Acceleration Values in g’s 

Date Time Location TTCI Accelerometers Independent Witne

Maximum 

Vertical 

Minimum 

Vertical 

Maximum 

Longitudinal

Minimum 

Longitudinal 

Maximum 

Vertical 

Maximum 

Vertical 

M

Lo

Roanoke 

December 4 5:59 p.m. to New 

Orleans 

2.1 -2.4 2.1 -3.5 2.8 -2.5 

Roanoke 

December 6 9:58 a.m. to New 2.4 -2.7 2.1 -1.7 1.8 -2.0 

Orleans New 

December 8 12:36 p.m. Orleans to 6.5 -5.9 2.9 -3.8 10.2 -9.0 

Chicago Roanoke 

December 6 7:20 p.m. to New 

Orleans 

25.3 -20.5 3.9 -9.3 21 -21 
32 

TYPICAL TIME DOMAIN DATA 

Figure A-4. Longitudinal Coupler Force, B-End, 

10.79 Second Duration–July 31, 2004 

Figure A-5. Vertical Coupler Force, B-End, 

4.43 Second Duration–December 5, 2004 
33 

Figure A-6. Dynamic Bolster Center Bowl Load, A-End, 

7.9 Second Duration–December 7, 2004 

Figure A-7. Dynamic Side Bearing Loads, B-End Bolster, 

Roll Motion–November 28, 2004 
34 

Figure A-8. Longitudinal and Vertical Coupler Force versus Time, 

A-End–December 7, 2004 

Figure A-9. Longitudinal versus Vertical Coupler Force, 

A-End–December 7, 2004 
35 

Figure A-10. Range Mean Histogram, A-End Longitudinal 

Coupler Force–July 10, 2004 

Figure A-11. Range Mean Histogram, B-End Longitudinal 

Coupler Force–July 10, 2004 
36 

Figure A-12. Range Mean Histogram, A-End Vertical 

Coupler Force–July 10, 2004 

Figure A-13. Range Mean Histogram, B-End Vertical 

Coupler Force–July 10, 2004 
37 

Figure A-14. Range Mean Histogram, A-End Bolster 

Center Bowl Load–July 10, 2004 

Figure A-15. Range Mean Histogram, A-End Bolster 

Side Bearing Load, Channel 6 End–July 10, 2004 
38 

Figure A-16. Range Mean Histogram, A-End Bolster 

Side Bearing Load, Channel 7 End–July 10, 2004 

Figure A-17. Range Mean Histogram, A-End Longitudinal 

Coupler Force–July 30, 2004 
39 

Figure A-18. Range Mean Histogram, B-End Longitudinal 

Coupler Force–July 30, 2004 

Figure A-19. Range Mean Histogram, A-End Vertical 

Coupler Force–July 30, 2004 
40 

Figure A-20. Range Mean Histogram, B-End Vertical 

Coupler Force–July 30, 2004 

Figure A-21. Range Mean Histogram, A-End Bolster 

Center Bowl Load–July 30, 2004 
41 

Figure A-22. Range Mean Histogram, A-End Bolster Side 

Bearing Load, Channel 6 End–July 30, 2004 

Figure A-23. Range Mean Histogram, A-End Bolster Side 

Bearing Load, Channel 7 End–July 30, 2004 
42 

Figure A-24. Range Mean Histogram, A-End Longitudinal 

Coupler Force–November 28, 2004 

Figure A-25. Range Mean Histogram, B-End Longitudinal 

Coupler Force–November 28, 2004 
43 

Figure A-26. Range Mean Histogram, A-End Vertical 

Coupler Force–November 28, 2004 

Figure A-27. Range Mean Histogram, B-End Vertical 

Coupler Force–November 28, 2004 
44 

Figure A-28. Range Mean Histogram, A-End Bolster 

Center Bowl Load–November 28, 2004 

Figure A-29. Range Mean Histogram, A-End Bolster Side 

Bearing Load, Channel 6 End–November 28, 2004 
45 

Figure A-30. Range Mean Histogram, A-End Bolster Side 

Bearing Load, Channel 7 End–November 28, 2004 
46 
47 

Acronyms 

AAR Association of American Railroads 

DTA damage tolerance analysis 

FAST Facility for Accelerated Service Testing 

FRA Federal Railroad Administration 

GB gigabytes 

GPS global positioning system 

lb pound/pounds 

RSI Railway Supply Institute 

SSWG Stub Sill Working Group 

TAG technical advisory group 

TC Transport Canada 

TCOE-TF Tank Car Operating Environment Task Force 

TTC Transportation Technology Center (the site) 

TTCI Transportation Technology Center, Inc. (the company) 

UDAQ unattended data acquisition system