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1. AGENCY USE ONLY (LEAVE BLANK) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED 

December 2006 Final Report 

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS 

Development of Conventional Passenger Cab Car End Structure Designs for Full Scale 

Testing CB035/RR28

6. AUTHOR(S) 

Ronald Mayville (Mayville and Assoc.), Richard Stringfellow (TIAX), and

Eloy Martinez (Volpe) 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

TIAX LLC* REPORT NUMBER 

Acorn Park 

Cambridge, MA 02140-2390 DOT-VNTSC-FRA-07-01 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

U.S. Department of Transportation 

Federal Railroad Administration 

1120 Vermont Avenue NW – Mail Stop 20

Washington, DC 20590

10. SPONSORING/MONITORING 

 AGENCY REPORT NUMBER 

DOT/FRA/ORD-06/20 

11. SUPPLEMENTARY NOTES U. S. Department of Transportation 

* under contract to: John A. Volpe National Transportation Systems Center 

 55 Broadway

 Cambridge, MA 02142-1093 

12A. DISTRIBUTION/AVAILABILITY STATEMENT 

This document is available to the U.S. public through the National Technical Information

Service, Springfield VA 22161

This document is also available on the FRA web site at www.fra.dot.gov. 

13. ABSTRACT (MAXIMUM 200 WORDS) 

The Volpe Center is supporting the Federal Railroad Administration’s full-scale testing program to understand and improve rail 

vehicle crashworthiness. The objective of one of the sets of tests in this program is determining the behavior of cab car end

structures in simulated grade crossing collisions. The project described in this report supported these tests by developing ready-tofabricate designs for the ends of passenger cars to represent a State-of-the-Art (SOA) and a 1990s cab car design, both of which 

are primarily strength-based designs. The report includes a description of prior research on cab car crashworthiness, the 

requirements for the designs, the designs themselves and the analyses used to demonstrate that the designs meet the requirements. 

Also included is a comparison between strains measured from quasi-static load tests and from finite element analyses. The results 

of the project show that the SOA end frame provides substantially greater strength and energy absorption capability than the 1990s 

design with little penalty in weight. 

14. SUBJECT TERMS 15. NUMBER OF PAGES 

Transportation, safety, crashworthiness, passenger rail vehicles, cab car end structure 92 

16. PRICE CODE 

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

 OF REPORT OF THIS PAGE OF ABSTRACT 

Unclassified Unclassified Unclassified

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

Prescribed by ANSI Std. 239-18 

298-102 

Preface 

This report describes the development and evaluation of two cab car end frame designs that were 

generated to investigate the implications of new industry standards and Federal regulations on 

crashworthiness and operations. Prior cab car crashworthiness research and existing and planned 

cab car designs for North American operation were reviewed. The two designs were then 

generated. Both hand and finite element analysis, including analysis for large deformations, 

were conducted to demonstrate that the designs meet the requirements. The end frames were 

then fabricated, integrated into existing cars, and instrumented and loaded to validate the design 

analyses. Finally, the end frames were used in full-scale grade crossing collision tests as part of 

a separate task. 

This work was performed as part of the Equipment Safety Research Program sponsored by the 

Office of Research and Development of the Federal Railroad Administration. The authors would 

like to thank Dr. Tom Tsai, Program Manager, and Claire Orth, Division Chief, Equipment and 

Operating Practices Research Division, Office of Research and Development, Federal Railroad 

Administration, for their support. The authors would also like to acknowledge the contributions 

of David Tyrell, Project Manager of the Volpe Center, for contributions in design and analysis, 

Patricia Llana, TIAX, who developed the finite element models, and Ebenezer Railcar Services, 

who fabricated the end frames. In addition the authors would like to acknowledge the 

contributions to design work from Kent Johnson and Scott Landrum from Premiere Engineering 

Inc. 

iii 
METRIC/ENGLISH CONVERSION FACTORS 

ENGLISH TO METRIC METRIC TO ENGLISH

LENGTH (APPROXIMATE) LENGTH (APPROXIMATE) 

1 inch (in) = 2.5 centimeters (cm) 1 millimeter (mm) = 0.04 inch (in) 

1 foot (ft) = 30 centimeters (cm) 1 centimeter (cm) = 0.4 inch (in) 

1 yard (yd) = 0.9 meter (m) 1 meter (m) = 3.3 feet (ft) 

1 mile (mi) = 1.6 kilometers (km) 1 meter (m) = 1.1 yards (yd) 

1 kilometer (km) = 0.6 mile (mi) 

AREA (APPROXIMATE) AREA (APPROXIMATE)

1 square inch (sq in, in2) = 6.5 square centimeters 1 square centimeter (cm2) = 0.16 square inch (sq in, in2) 

(cm2

) 

1 square foot (sq ft, ft2) = 0.09 square meter (m2) 1 square meter (m2) = 1.2 square yards (sq yd, 

yd2

) 

1 square yard (sq yd, yd2) = 0.8 square meter (m2) 1 square kilometer (km2) = 0.4 square mile (sq mi, mi2) 

1 square mile (sq mi, mi2) = 2.6 square kilometers 10,000 square meters (m2) = 1 hectare (ha) = 2.5 acres 

(km2

) 

1 acre = 0.4 hectare (he) = 4,000 square meters (m2) 

MASS - WEIGHT (APPROXIMATE) MASS - WEIGHT (APPROXIMATE) 

1 ounce (oz) = 28 grams (gm) 1 gram (gm) = 0.036 ounce (oz) 

1 pound (lb) = 0.45 kilogram (kg) 1 kilogram (kg) = 2.2 pounds (lb) 

1 short ton = 2,000 = 0.9 tonne (t) 1 tonne (t) = 1,000 kilograms (kg) 

pounds (lb) = 1.1 short tons 

VOLUME (APPROXIMATE) VOLUME (APPROXIMATE) 

1 teaspoon (tsp) = 5 milliliters (ml) 1 milliliter (ml) = 0.03 fluid ounce (fl oz) 

1 tablespoon (tbsp) = 15 milliliters (ml) 1 liter (l) = 2.1 pints (pt) 

1 fluid ounce (fl oz) = 30 milliliters (ml) 1 liter (l) = 1.06 quarts (qt) 

1 cup (c) = 0.24 liter (l) 1 liter (l) = 0.26 gallon (gal) 

1 pint (pt) = 0.47 liter (l) 

 1 quart (qt) = 0.96 liter (l) 

1 gallon (gal) = 3.8 liters (l) 

1 cubic foot (cu ft, ft

3

) = 0.03 cubic meter (m3) 1 cubic meter (m3) = 36 cubic feet (cu ft, ft3) 

1 cubic yard (cu yd, yd3) = 0.76 cubic meter (m3) 1 cubic meter (m3) = 1.3 cubic yards (cu yd, yd3) 

TEMPERATURE (EXACT) TEMPERATURE (EXACT) 

[(x-32)(5/9)] °F = y °C [(9/5) y + 32] °C = x °F 

QUICK INCH - CENTIMETER LENGTH CONVERSION 

0 1 2 3 4 5

Inches 

Centimeters 0 1 2 3 4 5 6 7 8 9 10 11 12 13

QUICK FAHRENHEIT - CELSIUS TEMPERATURE CONVERSION 

°F -40° -22° -4° 14° 32° 50° 68° 86° 104° 122° 140° 158° 176° 194° 212° 

°C -40° -30° -20° -10° 0° 10° 20° 30° 40° 50° 60° 70° 80° 90° 100° 

For more exact and or other conversion factors, see NIST Miscellaneous Publication 286, Units of Weights and Measures. Price $2.50 SD Catalog No. C13 10286 Updated 6/17/98 

iv 
Table of Contents 

List of Figures............................................................................................................................... vii 

List of Tables ................................................................................................................................. ix 

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

1. Introduction.................................................................................................................................3 

2. Prior Research Summary ............................................................................................................7 

2.1. Locomotive Crashworthiness Research ............................................................................................ 7

2.2. Evaluation of Cab Car Crashworthiness Design Modifications........................................................ 7

2.3. Approaches to Preventing Override and Lateral Buckling in Passenger Trains ............................... 8

2.4. End Beam Study................................................................................................................................ 9

2.5. Evaluation of Protection Strategies for Cab Car Crashworthiness ................................................. 11

2.6. Summary ......................................................................................................................................... 12

3. Requirements ............................................................................................................................15 

3.1. Crashworthiness Requirements....................................................................................................... 15

3.2. Other Requirements ........................................................................................................................ 18

4. Design Descriptions..................................................................................................................21 

4.1. 1990s Design................................................................................................................................... 21

4.2. State-of-the-Art Design................................................................................................................... 25

5. Design Analysis ........................................................................................................................29 

6. Fabrication ................................................................................................................................37 

7. Static Testing Results: Comparison With Analysis.................................................................39 

8. Summary...................................................................................................................................45 

References......................................................................................................................................47 

Acronyms.......................................................................................................................................49 

Appendix A. Examples of Single Level Cab Cars........................................................................51 

Appendix B. Requirements for the Cab Car End Frames.............................................................53 

Appendix C. Sections from the Drawings Used to Fabricate the End Frames.............................61 

Appendix D. Example Calculation for Collision Post Strength ...................................................73 

Appendix E. Tables of Strains from Test Measurements and Finite Element Analysis...............75 

v 

List of Figures 

Figure 1. An Example of a Cab Car in which the Operator is Positioned Immediately Adjacent 

to the Vehicle End .........................................................................................................4 

Figure 2. Schematic of the Cab Car End Structure Required to Support a 300x103

 lbf Corner 

Figure 3. Full-Scale End Beam/Side Sill Corner Post Support Element Designed and Tested to 

Load without a Step Well ..............................................................................................9 

Demonstrate Substantial Energy Absorption Capability.............................................11 

Figure 4. Some of the Structural Requirements for the 1990s Design ........................................16 

Figure 5. Some of the Structural Requirements for the SOA Design..........................................17 

Figure 6. One of the Budd Pioneer Cars Prior to Modification for this Program. (The Stairwell 

has been Removed)......................................................................................................19 

Figure 7. Fabricated 1990s End Frame Design ...........................................................................21 

Figure 8. Cross Section for the 1990s Design End Beam (Through the Collision Post).............22 

Figure 9. Cross Section of the 1990s Collision Post (Projections of the Gussets within the End 

Beam are Also Shown)................................................................................................23 

Figure 10. Cross Section of the 1990s Corner Post ......................................................................24 

Figure 11. Cross Sections of the 1990s Design AT Plate at the Collision Post (left) and Corner 

Post (right)...................................................................................................................25 

Figure 12. Fabricated SOA End Frame Design ............................................................................26 

Figure 13. Cross Section of the SOA Collision Post (projections of the gussets within the end 

beam are also shown)..................................................................................................27 

Figure 14. Cross Section of the SOA Corner Post........................................................................28 

Figure 15. Cross Section of the SOA Side Sill (Taken Between the Vestibule and the End 

Beam) ..........................................................................................................................28 

Figure 16. Model Used to Assess Various Load Cases for the SOA End Frame Design.............31 

Figure 17. Calculated Load-Load Point Displacement Plot for a Longitudinal Load Applied on 

the Collision Post 30 in. (762 mm) above the Floor (Load is for One Post) ..............31 

Figure 18. Deformed Model Corresponding to a Load Point Displacement of 7.75 in. (197 mm) 

on the Collision Post ...................................................................................................32 

vii 
Figure 19. Equivalent Plastic Surface Strain Contours Corresponding to a Load Point 

Displacement of 7.75 in. (197 mm) on the Collision Post..........................................32 

Figure 20. Load-Load Point Displacement Plot for a Longitudinal Load Applied on the Corner 

Figure 21. Deformed Model Corresponding to a Load Point Displacement of 6 in. on the Corner 

Figure 22. Equivalent Plastic Surface Strain Contours Corresponding to a Load Point 

Figure 23. Mises Surface Stress Contour Plot for the 100x103 lbf (445 kN) Lateral Corner Post 

Figure 24. SOA End Frame in Fabrication; This is the End Beam Before the Top Plate was 

Figure 25. SOA End Frame in Fabrication; This is the AT plate Before the Top Plate was 

Figure 26. End Frame Quasi-static Loading Test Arrangement; Strain Gage Locations are 

Post 18 in. (457 mm) above the Floor.........................................................................33 

Post at 18 in. (457 mm) above the Floor.....................................................................34 

Displacement of 6 in. (152 mm) on the Corner Post...................................................34 

Load at 18 in. (457 mm)..............................................................................................35 

Welded on ...................................................................................................................38 

Welded on ...................................................................................................................38 

Shown by the Small Colored Points............................................................................40 

Figure 27. Static Loads Applied to the End Frames .....................................................................41 

Figure 28. Comparison of Test to Analysis Results for the SOA Collision Post Loading Case: 

Strains at the Middle (Vertically) of the Collision Post..............................................42 

Figure 29. Comparison of Test to Analysis Results for the SOA Collision Post Loading Case: 

Figure 30. Comparison of Test to Analysis Results for the SOA Corner Post Loading Case: 

Figure 31. Comparison of Test to Analysis Results for the 1990s Collision Post Loading Case: 

Figure 32. Comparison of Test to Analysis Results for the Lateral Corner Post Loading Case: 

Figure 33. Comparison of Test to Analysis Results for the Lateral Corner Post Loading Case: 

Strains at the Left-Hand (Collision Post) Side of the Lateral Shelf............................42 

Strains at the Top of the Corner Post ..........................................................................43 

Strains at the Bottom of the Collision Post .................................................................43 

Strains in the Shelf ......................................................................................................44 

Strains in the Shelf (Rear Surface)..............................................................................44 

viii 
List of Tables 

Table 1. Full-Scale Passenger Equipment Tests to Assess Improvements in Crashworthiness .....3 

Table 2. Estimated Weight Increases for Higher Corner Post Support Structure Strengths...........9 

Table 3. A Comparison of the Predicted Collision Speeds Required to Produce 1 ft. and 3 ft. of 

Vehicle Crush for the Baseline and Modified End Structures........................................12 

Table 4. Summary of Cab Car End Structure Crashworthiness Standards and Requirements.....16 

Table 5. Detailed Finite Element Analysis Load Cases Conducted for the SOA Design ............30 

Table 6. Average Mechanical Properties for the A710, Gr. A, Class 3 Steel Used to Fabricate the 

1990s and SOA Endframes.............................................................................................37 

ix 
x 
Executive Summary 

This report describes the results of a program to design passenger rail car end frames for testing 

the differences in crashworthiness performance for cab cars that meet early to mid 1990s 

structural standards and cab cars designed to the current American Public Transportation 

Association (APTA) and Federal Railroad Administration (FRA) structural requirements, known 

as State-of-the-Art (SOA) design. The program is part of a larger one being conducted to 

investigate how crashworthiness of rail vehicles in various configurations and collision scenarios 

can be improved. The end frames discussed here were used to evaluate the increase in cab car 

protection for a particular grade crossing collision scenario. The development of the designs 

relied on a review of industry practice over the last few decades and on prior research in the area 

of cab car crashworthiness. A detailed set of design requirements was developed that included 

the applicable structural requirements, the need to meet operability requirements and the need to 

adapt to existing test cars. Hand and beam element finite element analyses were used to develop 

the 1990s design, while detailed finite element analyses, including large deformation 

calculations, were carried out to develop the SOA design. The end frames were fabricated from 

A710 steel and shipped to the Transportation Test Center (TTC) in Pueblo, Colorado, where they 

were attached to existing Budd Pioneer cars. Quasi-static loading tests were conducted on the 

frames after instrumentation by strain gages. Finally, the end frames were used in full-scale 

grade crossing collision tests in a separate program. 

The results of this project demonstrate that the new APTA requirements can be met with designs 

that are very similar to those needed to satisfy the requirements used in the 1990s. For example, 

there is only a 250 lbm (113 kg) difference between the 1990s and SOA end frame designs. In 

addition, the analyses and the full-scale tests demonstrate that stronger end frames provide a 

significant improvement in crashworthiness provided care is taken to assure that the collision and 

corner posts are designed to deform in a controlled and predictable manner under significant 

crush distances. For the purposed of this program ‘severe deformation’ of a post is taken as one 

times the depth of the post. 

A number of important issues were raised in the course of this program. The SOA design relied 

on the use of the side sill to support the back of the end beam at the base of the corner post. This 

is possible because of the general acceptance by industry to eliminate the step well at the 

operator’s corner. If a step well were present so that such a structural detail could not be used, 

the weight penalty would be much greater. The ability to achieve a prescribed amount of 

deformation in the end frame posts has also been raised as an important issue. The SOA design 

was developed with the requirement that the post deform an amount equal to one times its depth 

without cracking. This requirement was originally part of an accepted standard released by 

APTA in 1999, but eventually it was changed to a recommended practice. The recommended 

practice addresses deformability in an indirect manner by requiring very strong connections 

between the posts and their connections. 

The very successful performance of the SOA design in the full-scale test relative to the 1990s 

end frame demonstrates the potential for crashworthiness improvement. 

1 
2 
1. Introduction 

The Volpe National Transportation Systems Center (Volpe Center) is supporting the FRA’s 

analysis and full-scale testing program to understand and improve rail vehicle crashworthiness. 

The objectives of these tests are to establish the crashworthiness of vehicles built to current 

standards and to assess the improvements provided by new requirements and new technologies. 

Several tests have already been conducted and more are planned, as shown in Table 1. These 

include crash tests in which a single car, and two coupled cars collide with a rigid surface, and a 

test in which a moving, cab car-led train collides with a standing locomotive-led train. The tests 

characterize vehicle trajectories, deformation modes, secondary impact environment and energy 

absorption. The tests for equipment essentially built to today’s standards are complete and the 

tests with crash energy management systems began at the end of 2003. Another set of completed 

tests focused on the behavior of cab car end structures in simulated grade crossing collisions. 

The project described in this report supported these tests by developing ready-to-fabricate 

designs for the ends of passenger cars to represent an SOA and a 1990s cab car design, both of 

which are primarily strength-based designs. 

Table 1. Full-Scale Passenger Equipment Tests to Assess Improvements in 

Crashworthiness 

Test Conditions Conventional 

Design Equipment 

Improved Crashworthiness 

Design Equipment 

Single car collision into a 

rigid, flat barrier 

November 16, 1999 December 3, 2003 

Two coupled car collision 

with a rigid, flat barrier 

April 4, 2000 February 26, 2004 

Cab car led train collision with 

a locomotive led train 

January 31, 2002 March 2006 

Single car collision with a 

steel coil 

June 4, 2002 June 7, 2002 

Cab cars are passenger-carrying rail vehicles located at the very end of the train. The operator is 

positioned at the end of the cab car where he or she has good visibility of the track. In the United 

States, the cab car is designed to also be used as a passenger car within the train. This requires 

that the cab car have the same layout as a pure passenger car. This results in the operator being 

located immediately adjacent to the flat end wall of the vehicle. Figure 1 shows an example of a 

cab car operated in the U.S. The end wall does include two collision posts, one on each side of a 

doorway and a post at each corner. Nevertheless, the proximity of the operator to the very end of 

the car puts him or her at greater risk in the event of a collision with an object or another train. 

Passenger car ends have been required to possess collision posts of substantial strength since the 

1950s. The need for such structures was highlighted by a serious collision in which override and 

penetration of the passenger compartment occurred [1]. Around the 1980s it became standard 

3 
practice – but not a Federal requirement – to also require strong corner posts at the end of 

passenger and cab cars. 

Figure 1. An Example of a Cab Car in which the Operator is Positioned Immediately 

Adjacent to the Vehicle End 

Since the mid 1990s there has been renewed research into determining how increasing the 

strength of passenger end frames would improve rail vehicle crashworthiness in a practical 

manner. This work has in part been motivated by some serious accidents in which there were 

fatalities because of the crush and intrusion into the ends of the cars. For example, a collision 

between a cab car-led train and a steel coil on a trailer truck in Portage, Indiana in 1998 resulted 

in penetration of the coil into the car and three fatalities [2]. (The full-scale grade crossing tests 

were modeled after this accident.) There was also a collision between a locomotive-led train and 

a cab car-led train at a switch in Secaucus, New Jersey in 1996 that crushed the corner of the cab 

car and also resulted in three fatalities [3]. The research that has been conducted includes design 

layout development, finite element analysis and component testing [4-6]. The results have 

demonstrated that a substantial improvement in crashworthiness is feasible. 

In the past few years, this research together with industry group discussions on the development 

of new standards and recommendations have led to the adoption of higher strength requirements 

for both the collision and corner posts for both passenger and cab cars. These new requirements 

are given in the APTA SS-C&S-034-99, Standard for the Design and Construction of Passenger 

Railroad Rolling Stock, and the Code of Federal Regulations, Title 49, Part 238 [7,8]. 

Since the requirements are relatively new, there is a desire to better quantify the improvement 

they provide in collisions. The full-scale grade crossing tests described earlier are one method 

that was pursued to demonstrate this. 

4 
The objective of the project described in this report was to develop two cab car end frame 

designs: the 1990s design and the SOA design. The intent of the 1990s design was to represent 

structural requirements in practice for cab car end frames in the early to mid 1990s, prior to the 

passage of the new 49 CFR Part 238 or the adoption of APTA SS-C&S-034-99. The SOA 

design is meant to represent the structural requirements for vehicles that are and will be designed 

to the recent APTA and Federal requirements. 

The approach taken in the project was to review existing and planned designs, define design 

requirements, develop and fabricate modification designs, quasi-statically test the two designs, 

and compare the test results between the conventional and modified designs. Information on 

existing and planned designs was obtained from industry sources, particularly from members of 

the APTA Passenger Rail Equipment Safety Standards Construction/Structural (PRESS-C&S) 

committee. The designs were developed after generating concepts for the various structural 

elements. Each element or system of elements was then analyzed using simple strength of 

material hand calculations or finite element analysis. Industry participants provided review of 

these designs. The detailed engineering was then carried out and a company specializing in rail 

vehicle structures fabricated the end frames. The finite element models were also used to 

generate values of strain corresponding to the quasi-static test loads, and these were compared to 

the test data. Information on the full-scale grade crossing collision tests may be found in 

references [9,10]. 

5 

2. Prior Research Summary 

Several studies related to the strengthening of cab car end structures have been conducted 

previously under the FRA/Volpe Center crashworthiness program. The projects demonstrated 

that increased strength provides a benefit in occupant protection in grade crossing and offset 

collisions. The work has also explored the feasibility of increasing strength practically for 

various approaches, including the use of the side sill to support the corner loads. This section 

provides a summary review of these studies, particularly as they apply to the issue of end frame 

strengthening. 

2.1. Locomotive Crashworthiness Research 

Cab car crashworthiness was first investigated in 1995 as part of a larger project on locomotive 

crashworthiness [11]. The objective was to determine the crashworthiness of cab cars in 

centered and offset collisions and to investigate the potential benefit of increasing component 

strength. In particular, collision dynamics analyses were conducted to simulate the impact 

between the underframe of a single locomotive and a cab car-led train for two cab car corner post 

strengths: one in which the ultimate strength at the underframe was 150x103 lbf (667 kN) ─ the 

structural practice at the time ─ and one in which the strength was 600x103 lbf (2,669 kN). The 

deformation response for the 150x103 lbf (667 kN) strength case was determined from 

approximate, nonlinear finite element analysis. This response was then scaled by a factor of four 

for the 600x103 lbf (2,669 kN) corner post strength case. There was no expectation at the time 

that a 600x103 lbf (2,669 kN) strength could be practically achieved; it was selected to determine 

the effect of a large increase in strength on crush. No work was conducted in that study on 

exactly how such a high strength could be achieved or on the implications on the support 

structure, weight and cost. 

The results of the analyses indicated that the amount of corner post crush could be reduced from 

over 6 ft. to less than 2 ft. at a closing speed of 15 mph (24 km/h) for impact with a locomotive. 

The effects of fracture were not treated in the analysis predictions, but the importance of a 

ductility measure was considered. 

2.2. Evaluation of Cab Car Crashworthiness Design Modifications 

Some additional work on corner strength was conducted subsequent to the locomotive 

crashworthiness study [11]. This work involved approximate calculations on the increase in 

section size that would be needed to achieve an end beam strength, for a load applied at the base 

of the corner post, of 300x103

 lbf (1334 kN). Side sill support was not included. The additional 

weight was estimated to be only 150 lbm (68 kg), but it is now recognized that the analysis did 

not properly account for the structure needed to resist the loads within, for example, the draft sill. 

Nevertheless, the collision analyses demonstrated the benefits on crashworthiness that increased 

corner strength could provide. 

7 
2.3. Approaches to Preventing Override and Lateral Buckling in Passenger Trains 

Some information applicable to the strength of corner structures in passenger cars may be found 

in a study completed in 1999 on methods to prevent override and lateral buckling. One of the 

approaches investigated in that study was a push back and locking coupler, which, together with 

a stronger corner structure, was intended to provide moment resistance against the yaw motion 

associated with lateral buckling. In particular, a structural concept was developed to achieve 

corner strengths of 300x103 and 600x103 lbf (1,334 and 2,669 kN), with and without step wells; 

these strengths refer to the ultimate strength for a longitudinal load applied at the end of the end 

beam, at which the base of the corner post would be located. The analysis utilized beam element 

finite elements and was considerable more detailed than the analysis conducted in [12]. 

Figure 2 shows the concept structure developed for the case in which the end beam must carry a 

load of 300x103 lbf (1,334 kN) without the benefit of a side sill load path. There are, of course, 

many other ways in which such a strength could be achieved. (Note: an existing Massachusetts 

Bay Transportation Authority (MBTA) car was used for the platform on which the analysis was 

based.) Table 2 lists the estimated increase in weight associated with two levels of increased 

corner strength for the cases in which the side sill can and cannot be used as a load path. These 

weight estimates agree closely with the estimates of the present study. 

8 
Source: [12] 

Figure 2. Schematic of the Cab Car End Structure Required to Support a 300x103 lbf 

Corner Load without a Step Well 

Table 2. Estimated Weight Increases for Higher Corner Post Support Structure Strengths 

WEIGHT INCREASE FOR CORNER STRENGTH* 

Configuration 300x103 lbf (1334 kN) 600x103 lbf (2669 kN) 

Stepwell 1,100 lbm (499 kg) 4,650 lbm (2109 kg) 

No stepwell 150 lbm (68 kg) 500 lbm (227 kg) 

Source: [12] 

*per vehicle end 

2.4. End Beam Study 

Around 1998, the authors conducted an experimental study to further investigate the feasibility 

of increasing the strength of a rail car corner structure under impact conditions [5]. The focus in 

that project was on the end beam, which ultimately must support any load placed at the base of 

the corner post. Two end beam designs were developed: one whose design ultimate strength 

9 
was 150x103

 lbf (667 kN) at its end (where the corner post would be) and one with a design 

ultimate strength of 400x103 lbf (1,779 kN). The strength in the latter case was achieved by 

utilizing a structural member that corresponds to the side sill having been brought to the rear face 

of the end beam. Extending the side sill eliminates the opportunity for a step well at the 

particular corner in question. However, in 1998, discussions had begun in industry about 

eliminating the step well at the operator’s corner just for this purpose. 

Two end beam structures were fabricated and then tested. The baseline (150x103 lbf, or 667 kN, 

strength) design was tested both quasi-statically and in a drop tower apparatus. The modified 

(400x103

 lbf, or 1,779 kN, strength) design was tested only in the drop tower apparatus. 

The results of these tests and of the accompanying finite element analyses were at first 

surprising. The modified end beam was found to absorb only twice as much energy as the 

baseline design in about 0.5 ft. (0.2 m) of crush, even though the ratio of the design strengths was 

four. As it turns out, the reason for this difference in ratios has to do with the difference in load 

path for the two designs. In the baseline case, the load is carried only by bending of the end 

beam. On the other hand, the extended side sill in the modified design carries most of the load in 

the initial portion of the deformation, but, due to a folding-type buckling that occurs, the side 

sill’s load carrying capacity drops off as the load in the end beam increases. Figure 3 shows the 

beginning of the folding deformation in the modified test article ‘side sill’ after an impact in the 

drop tower. 

The test results also showed that the baseline end beam fractured after about 0.5 ft. (0.2 m) of 

end displacement. Although not tested to fracture, the end beam in the modified design would 

also have fractured at this displacement, since its mode of deformation was not substantially 

different than in the baseline case. 

Another result from this study was that the measured ultimate strength of the end beam was 

substantially greater than the design value: the peak load in the quasi-static test, for a load 

applied at the very end of the beam, was 240x103 lbf (1,068 kN) compared to the design value of 

150x103 lbf (667 kN). This difference is directly attributable to material properties that were 

substantially greater than the minimum required values that were used in design. On the other 

hand, use of the actual material properties in the nonlinear finite element analysis, which, in this 

case, did include the effects of material fracture, provided accurate predictions of the end beam 

strength. 

Conventional structural steel, A572-50, was used to fabricate the designs and the weight increase 

for the modified design was approximately 80 lbm (36 kg), per corner. 

There are several implications of the study. First, it is feasible to increase the strength of a cab 

car supporting corner structure substantially without a significant weight penalty, particularly 

when the side sill can be used to carry load. Furthermore, this strength increase provides an 

increase in energy absorption, and therefore, crashworthiness. However, when the load is 

applied at the base of the post, and, therefore, to the end of the end beam, the increase in energy 

absorption is less than what would be predicted by the ratio of the strengths for the particular 

design approach in which the side sill is used to provide strength. Furthermore, the energy 

absorption is limited by the deformability of the structure; in the case of these end beam designs, 

10 
fracture occurred after 0.5 ft. (0.2 m) of corner displacement. Another important implication is 

that the use of nonlinear finite element analysis, which is becoming common in the rail vehicle 

industry, provides an opportunity to reduce weight while improving crashworthiness. 

Figure 3. Full-Scale End Beam/Side Sill Corner Post Support Element Designed and 

Tested to Demonstrate Substantial Energy Absorption Capability 

2.5. Evaluation of Protection Strategies for Cab Car Crashworthiness 

A study completed in 2000 specifically addressed the potential crashworthiness benefits of 

increasing corner strength for laterally offset, or corner, collisions [4]. The work was primarily a 

finite element study that accounted for large deformations in the collisions. The two relevant 

scenarios investigated were: a collision between a locomotive and the corner of a cab car (as 

occurred in an accident in Secaucus, NJ); and a collision between a cab car corner post and a 

steel coil (similar to what occurred in the Portage, IN accident). In the case of the simulated 

locomotive collision, the load is applied at the base of the corner post, while for the steel coil, the 

load is applied at about 36 in. (911 mm) above the underframe. The baseline strength for the 

corner structure was again 150x103

 lbf (667 kN), and increased corner strengths of 300x103 lbf, 

(1,334 kN) and 500x103 lbf (2,224 kN) were analyzed. Detailed structural designs were not 

developed for the modified structures. Rather, elements within the finite element model were 

either extended, for the side sill, or simply increased in thickness, for the end beam, until the 

desired strengths ─ as determined by the finite element analysis ─ were achieved. The effects of 

increasing the strength of other elements, such as the AT plate and the lateral shelf, were also 

investigated. The increase in structural weight associated with these modifications was not 

calculated. 

11 
Several different combinations of collision object, impact location, strength modification 

approach and collision speed were analyzed. An example set of results is shown in Table 3. The 

results in this table are given in terms of the collision speeds that produced 1 ft. and 3 ft. (0.3 m 

and 0.9 m) of predicted crush for a collision of a 40x103 lbm (18x103 kg) object with the very 

base of the corner post; 1 ft. (0.3 m) of crush is intended to correspond approximately with the 

crush beyond which the cab operator is seriously threatened, and 3 ft. (0.9 m) corresponds to the 

crush beyond which the passengers are expected to be threatened. 

Table 3. A Comparison of the Predicted Collision Speeds Required to Produce 1 ft. and 3 

ft. of Vehicle Crush for the Baseline and Modified End Structures. 

Case Corner Strength at 

Base (103 lbf (kN)) 

Collision Speed at 

1 ft. of Crush (mph 

(km/h)) 

Collision Speed at 

3 ft. of Crush (mph 

(km/h)) 

Baseline 150 (667) 11.5 (18.5) 18.7 (30.1) 

Extended side sill 

only 

300 (1334) 13.6 (21.9) 22.3 (35.9) 

Extended side sill 

and stronger end 

beam 

500 (2224) 15.4 (24.8) 26.1 (42.0) 

Source:[2] 

The results of Table 3 indicate that there is a significant although small improvement in 

crashworthiness by increasing the strength of the corner structure for this collision scenario. The 

analyses also indicated that fracture would occur after about 20 in. (508 mm) of end beam 

displacement in contrast to the 6 in. (152 mm) observed in the end beam study described above. 

This is likely attributable to differences in end beam design and the approximate manner in 

which fracture was predicted in the finite element analyses. 

Finally, the protection strategy study also examined the use of crash energy management, or 

crush zone, approaches in providing increased cab car protection. In this case, the entire end of 

the car absorbs energy and displaces backward during the collision. The operator is then either 

provided with an escape route or a refuge area. Such an approach more directly addresses the 

physical requirement that energy must be absorbed in all collisions. Rather than requiring the 

corner structure to absorb all of this energy, the entire end participates in the process. 

2.6. Summary 

The primary result of the previous studies just described is that cab car occupant protection 

against crush in offset collisions can be improved by increasing the strength of the end frame 

components. This benefit comes from the ability of the stronger corner structures to absorb more 

energy. 

Less clearly demonstrated was the feasibility of increasing the strength in a practical manner. 

When the side sill can be used as a load path to support the required load at the base of the corner 

post, there appears to be little weight penalty in the structure. Of course, in this case the stepwell 

12 
must be eliminated and this has an effect on operations. Nevertheless, such an approach has 

been accepted in industry, at least for the operator’s corner. If the side sill cannot be used as a 

load path to support the corner loads then the previous work indicates that there will be a 

significant weight penalty. 

In either case, some of the previous work suggests that the potential increase in crashworthiness 

protection is limited by the deformability of the structural elements. Even though the strength 

may be increased substantially, the effective amount of energy absorption may still be relatively 

low, thus providing only a small increase in tolerable collision speed. This suggests that the 

crash energy management approach, in which the entire end of the cab car absorbs energy, be 

examined in greater detail. It also suggests that developing end frame designs, which deform 

gracefully under ‘severe deformations’ prior to failure of the support structure is warranted. 

13 
14 
3. Requirements 

A requirements document was generated as part of the design process to provide guidance for 

generating concepts and quantitative measures for evaluating the design. The requirements for 

the two designs were developed from group discussions with industry and review of existing car 

structures. Important input included: 

• Federal requirements; 

• industry standards; 

• specifications for existing and planned rail vehicles; and 

• discussions with industry personnel active in rail vehicle design. 

Input from members of APTA’s PRESS-C&S Committee was very useful in this regard. The 

detailed requirements for the two designs, which include crashworthiness, operational, testing, 

fabrication, and physical requirements, are included in Appendix B. This section provides a 

summary of the key requirements. 

Several cab cars have been designed and built over the last 10-15 years. A partial list of singlelevel passenger rail cars is given in Appendix A. For some of these cars, the design team had 

access to the specifications and drawings. These were reviewed to glean features common to the 

various designs. 

3.1. Crashworthiness Requirements 

Table 4 summarizes the crashworthiness requirements used in this project for the two the cab car 

end frame designs. Figures 4 and 5 provide some of the information schematically. 

15 
Table 4. Summary of Cab Car End Structure Crashworthiness Standards and 

Requirements 

Standard/Requirement 

Component 1990s Design SOA Design 

Collision Post 

(must be present at 

the 1/3 points along 

the width of the 

vehicle) 

• 300x103 lbf (1,334 kN) at the floor 

without exceeding the ultimate shear 

strength 

• 300x103 lbf (1,334 kN) at 18 in. (457 

mm) above the floor without 

exceeding the ultimate strength 

• Both requirements apply for loads 

applied ±15° inward from the 

longitudinal 

• If reinforcement is used to achieve the 

strength it must extend fully to 18 in. 

(457 mm) and then taper to 30 in. (762 

mm) above the underframe 

• 500x103 lbf (2,224 kN) at the floor 

without exceeding the ultimate shear 

strength 

• 200x103

 lbf (890 kN) at 30 in. (762 mm) 

without exceeding the ultimate strength 

• 60x103

 lbf (267 kN) applied anywhere 

without yield 

• All requirements apply for loads applied 

±15° inward from the longitudinal 

• Strengths must be achieved without 

failing connections 

• The post must be able to deform 

substantially without failing the 

connections 

Corner Post 

(must be present at 

the extreme corners 

of the vehicle) 

• 150x103 lbf (667 kN) at the floor 

without exceeding the ultimate shear 

strength 

• 30x103

 lbf (134 kN) at 18 in. (457 

mm) above the floor without 

exceeding the material yield strength 

• Both requirements apply for loads 

applied anywhere between 

longitudinal to transverse inward 

• 300x103 lbf (1,344 kN) at the floor 

without exceeding the ultimate shear 

strength 

• 100x103

 lbf (445 kN) at 18 in. (460 mm) 

above the floor without exceeding the 

yield strength 

• 45x103

 lbf (200 kN) applied anywhere 

along the post without yield 

• All requirements apply for loads applied 

anywhere between longitudinal inward 

to transverse inward 

Lateral Member 

(must be present 

between the corner 

and collision posts 

just below the cab 

window) 

• 15x103 lbf (66.7 kN) applied in the 

longitudinal direction anywhere 

between the corner and collision post 

without yield 

• 15x103 lbf (66.7 kN) applied in the 

longitudinal direction anywhere between 

the corner and collision post without 

yield 

• Include a bulkhead in the opening below 

the shelf. 

Figure 4. Some of the Structural Requirements for the 1990s Design 

16 
Figure 5. Some of the Structural Requirements for the SOA Design 

The intent behind the increases in strength defined in the SOA design is, in large part, to raise the 

amount of energy that can be absorbed in a collision. At one point, the APTA standard included 

the following paragraph: 

‘... post and its supporting structure shall be designed so that when it is overloaded 

... failure shall begin as bending or buckling in the post. The connections of the post 

to the supporting structure, and the supporting car body structure, shall support the 

post up to its ultimate capacity. The ultimate shear and tensile strength of the 

connecting fasteners or welds shall be sufficient to resist the forces causing the 

deformation, so that shear and tensile failure of the fasteners or welds shall not 

occur, even with severe deformation of the ... post and its connecting and 

supporting structural elements.’ 

The APTA standard did not specify how much severe deformation the structural members must 

sustain. Engineers in the industry suggested that deformation equal to the depth of the structural 

member is considered ‘severe.’ A deformation requirement was not explicitly included in the 

APTA standard. The subject remains a topic of debate due to a change in the standard based 

upon requests from rail car manufacturers. The standard has been changed to a recommended 

practice. This occurred because the manufacturers desired an explicit definition of ‘severe 

deformation.’ In addition to the definition, the manufacturers requested clearer guidance in 

terms of how to demonstrate compliance to transportation authorities that specify testing of 

‘severe deformation.’ 

Another area for which there was and continues to be discussion relates to the elimination of the 

stepwell at the end of the car to enable the use of the side sill to support the required 300x103

 lbf 

(1334 kN) corner post load. The research to date, including the prior research summarized above 

and the results of the present study, demonstrate that use of the side sill for direct support of the 

load permits a design with little weight penalty. Yet there are evidently situations in which a 

step well is still required. To accommodate this case, the APTA standard permits the use of a 

lower longitudinal strength requirement at the non-operator side of the car, provided the adjacent 

17 
body corner post (usually located on the inboard side of the doorway) is designed to meet the 

300x103 lbf (1,334 kN) longitudinal strength requirement. It remains a topic of debate whether 

the operator’s side can be practically designed with a step well and meet the current strength 

requirements. 

Still another area of discussion was whether the collision and corner posts should be required to 

penetrate and be joined with the upper and lower surfaces of the end beam. Older standards did 

not require this for the corner post but the current standard requires it explicitly. It is an 

important requirement because it ensures a substantially stronger and more deformable 

connection to the end frame as demonstrated by the full-scale grade crossing tests that were 

eventually conducted. 

There are some requirements that are now in the APTA standard that were not accepted at the 

time the project being described in this report was conducted. These came about as a 

compromise for repealing the then accepted ‘severe deformation’ requirement. These are 

strength requirements for the connections between the collision and corner posts and the AT 

plate. The shear strength for the joint between the collision post and the AT plate must be 

70x103 lbf (311 kN). In addition, the connection must carry a tensile load (downward along the 

post) of 30x103 lbf (133 kN) for the collision post and 22.5x103 lbf (100 kN) for the corner post. 

These requirements are another indirect way of ensuring that the post deforms before the 

connection fails. Although not checked, it is likely that the SOA design satisfies these 

requirements. 

3.2. Other Requirements 

In addition to the crashworthiness requirements, it was also important to ensure that the designs 

were practical with regard to other operational and physical requirements. These requirements 

include accommodation for conventional coupling components and restricting dimensions to fit 

into standard vehicle envelopes. 

The designs also had to be adaptable to two similarly built test cars (one for each design) located 

in Pueblo, Colorado at TTC. These Budd Pioneer vehicles were used for the two previous fullscale collision tests but still each had one end in a condition usable for this program as revealed 

by examination of the cars and the corresponding drawings. The vehicles, built in the 1950s, 

possess stairwells on each side of a draft sill that meets the 800x103

 lbf (3,559 kN) buff load 

requirement. There is a buffer beam, or end beam, at the very end that contains the bellmouth 

and to the sides of which the collision posts are attached. Only a light plate structure protruded 

laterally from the end beam and there were no significant corner posts. Figure 6 shows a 

photograph of the structure prior to modification. The preliminary assessment conducted in this 

study indicated that the collision posts, end beam and corner structure would need to be replaced 

for both the 1990s and SOA design test cars. 

18 
Figure 6. One of the Budd Pioneer Cars Prior to Modification for this Program. (The 

Stairwell has been Removed) 

19 

4. Design Descriptions 

The sections that follow provide summary descriptions of the 1990s and SOA designs developed 

in this program. There are a number of common features to the two designs. These include the 

geometry of the end beam and the use of A710 Class 3 steel for all components. The connection 

detail between the end beam and the draft sill of the existing Budd car is also the same for both 

designs. These will be described in greater detail in the sections that follow. Sections from the 

drawings corresponding to some of the individual components are included in this section and in 

Appendix C. 

4.1. 1990s Design 

A photograph of the fabricated 1990s end frame provides an overview of the design and its 

attachment to the existing test car, Figure 7. 

Collision Post 

Roof Connection 

Buffer Beam 

AT Plate 

Shelf 

Corner Post 

Figure 7. Fabricated 1990s End Frame Design 

21 
The end beam consists of a closed rectangular cross section, 7.31 x 19.0 in. (186 x 483 mm), 

fabricated from 0.375-inch (9.5-mm) thick plate as shown in Figure 8. It contains internal 

gussets, some of which line up with the webs of the draft sill on the existing car. The collision 

posts penetrate both the upper and lower flanges of the end beam, while the corner posts 

penetrate only the upper flange, consistent with some of the 1990s era designs we reviewed. The 

end frame includes a new bellmouth as part of the assembly. (Additional sections from the 

drawings used to fabricate the end frames are included in Appendix C.) 

Figure 8. Cross Section for the 1990s Design End Beam (Through the Collision Post) 

The collision post has a rectangular cross section, 7.75 x 6.5 in. (197 x 165 mm), fabricated from 

0.375-inch (9.5-mm) plate, as shown in Figure 9. The post is reinforced by two lugs, each 0.25 

in. (6.4 mm) thick and extending to 34 in. (864 mm) above the underframe on the front and back 

of each post. 

22 
Figure 9. Cross Section of the 1990s Collision Post (Projections of the Gussets within the 

End Beam are Also Shown) 

The corner posts have a square cross section, 4.5 in. (114 mm) on a side, fabricated from 0.25-

inch (6.4-mm) plate, as shown in Figure 10. The corner posts are reinforced on two adjacent 

sides by 0.25-inch thick (6.4 mm) lugs that extend 27.25 in. (692 mm) above the underframe. 

23 
Figure 10. Cross Section of the 1990s Corner Post 

A lateral shelf member spans between the collision and corner post on each side. It consists of a 

channel, 5.0 x 1.75 in. (127 x 44.5 mm) formed from 0.25-inch (6.4-mm) plate. The top of the 

shelf is 30 in. (762 mm) above the underframe. 

The collision and corner posts are supported at the top by an AT plate that also has a closed, 

rectangular cross section. Its dimensions are 12.0 x 3.75 in. (305 x 95 mm) and it is fabricated 

from 0.25-inch (6.4-mm) plate (Figure 11). The collision and corner posts penetrate only the 

lower flange of the AT plate. 

24 
Figure 11. Cross Sections of the 1990s Design AT Plate at the Collision Post (left) and 

Corner Post (right) 

The end frame is attached to the existing car at three locations: the draft sill and the two 

longitudinal roof members. There is no connection at the side sill in the 1990s design as there is 

in the SOA design. The connection at the draft sill is made at both webs and the top flange. 

There are also two, transverse reinforcing gussets between the end beam and the end of the draft 

sill. 

The connection of the longitudinal roof members to the existing car structure was designed but 

then modified to fit the existing vehicle in its present condition. Each roof member extending 

from the rear of the anti-telescoping plate is essentially a channel section fabricated from an 

angle and a bar. The open part of the channel is attached to the existing (outer) roof sheet. The 

end of this built-up member bears against a flat plate welded onto the vestibule wall. Another 

angle and a transverse gusset reinforce the end connection. 

4.2. State-of-the-Art Design 

Figure 12, the fabricated SOA end frame, provides an overview of the design and its attachment 

to the existing test car. The primary features of the SOA design that differ from the 1990s design 

are as follows: 

• The corner posts extend through both the top and bottom flanges of the end beam 

• The collision and corner posts penetrate both flanges of the AT plate 

• There is a side sill element that extends up to the end beam 

• A bulkhead exists in the opening defined by the collision post, shelf, corner post, and 

underframe. 

25 
Collision Post 

Buffer Beam 

AT Plate 

Shelf 

Corner Post 

Side Sill 

Roof Connection 

Bulkhead 

Figure 12. Fabricated SOA End Frame Design 

The end beam has the same dimensions as for the 1990s design. In the case of the SOA design 

the collision posts and the corner posts penetrate both the upper and lower flanges of the end 

beam. 

The collision post again has a rectangular cross section, 7.75 x 6.5 in. (197 x 165 mm), fabricated 

from 0.375-inch (9.5-mm) plate, but the reinforcing lugs have a thickness of 0.375 in. (9.5 mm), 

and extend to 46 in. (1,168 mm) above the underframe on each side of each post (Figure 13). 

The corner posts have a square cross section, but for the SOA design they are 6.0 in. (152 mm) 

on a side, fabricated from 0.31-inch (7.9-mm) plate (Figure 14). The corner posts are reinforced 

on all four sides by 0.31-inch (7.9-mm) thick lugs that extend 27.25 in. (692 mm) above the 

underframe. The lugs are not required for shear reinforcement; instead they are present for 

‘severe deformation’ bending requirements. 

A lateral, shelf member is the same in this design as in the 1990s design. However, the SOA 

design includes a 0.25-inch (6.4-mm) thick bulkhead plate welded to the collision post, shelf, 

corner post and underframe; a part of this can be seen in Figure 13. 

26 
The AT plate has the same dimensions as in the 1990s design. In the SOA design, the collision 

and corner posts penetrate both the lower and upper flanges of the AT plate. 

The SOA end frame is attached to the existing car at five locations: the draft sill, the two roof 

rails, and the two side sills. The connections to the draft sill and roof rails are essentially 

identical to the 1990s design. Each side sill is a closed rectangular section, 4.94 x 5.81 in. (125.5 

x 147.6 mm), fabricated from two 0.25-inch (6.4-mm) thick angles, as shown in Figure 15. The 

connection to the back of the end beam includes a 0.75-inch (19-mm) thick pad to distribute the 

bearing load. The connection of the side sill is made to the rest of the car by: a) welding the end 

of the inside angle to a plate on the face of the cross tie; and b) by extending the outer angle to 

the body bolster and welding the edges to the side plate and side sill. 

The SOA end frame weight is 250 lbm (113 kg) more than the 1990s design. 

Figure 13. Cross Section of the SOA Collision Post (projections of the gussets within the 

end beam are also shown) 

27 
Figure 14. Cross Section of the SOA Corner Post 

Figure 15. Cross Section of the SOA Side Sill (Taken Between the Vestibule and the End 

Beam) 

28 
5. Design Analysis 

The preliminary design of the various structural members was initially carried out by conducting 

hand and beam element finite element analysis for both the 1990s and the SOA designs. No 

other analysis was carried out for the 1990s design, consistent with the design techniques 

generally used in the 1990s design era. However, a detailed finite element model was generated 

for post-test analysis of the 1990s design. On the other hand, finite element analysis, including 

the simulation of detailed shapes of each structural member, was conducted for the SOA design 

after the draft engineering drawings had been generated. The SOA design was then modified, as 

needed, to satisfy the various requirements and the detailed finite element analysis repeated. 

This section describes the analysis conducted to demonstrate that the final SOA design meets the 

new strength requirements. 

For some structural members and load cases, even for the SOA design, only hand calculations 

were used to demonstrate that a particular requirement was satisfied. These components and 

load cases included: 

• Collision post shear strength at the base 

• Collision post strength for the cases in which the load is applied up to 15 degrees to the 

longitudinal axis 

• Corner post shear strength at the base 

• Shelf strength under longitudinal loading anywhere along its length. 

Appendix D gives an example of the hand calculation approach used to calculate the ultimate 

strength of the collision post when loaded above the underframe. 

Table 5 lists the load cases for which detailed finite element analysis was used to demonstrate 

compliance of the SOA design with the requirements. 

29 
Table 5. Detailed Finite Element Analysis Load Cases Conducted for the SOA Design 

Component Load Case 

Collision Post Longitudinal load at 30 in. (762 mm) above the underframe; ultimate strength must 

be at least 200,000 lbf (890 kN); deformation of at least one times the depth of the 

post 

60,000 lbf (267 kN) at a height of 75 percent of the distance between the 

underframe and the AT plate; longitudinal direction; no yielding 

60,000 lbf (267 kN) at a height of 75 percent of the distance between the 

underframe and the AT plate; transverse direction; no yielding 

Corner Post 100,000 lbf (445 kN) at 18 in. (457 mm) above the underframe in the longitudinal 

direction; no yielding 

100,000 lbf (445 kN) at 18 in. (457 mm) above the underframe in the lateral 

direction; no yielding 

45,000 lbf (200 kN) at the AT plate; longitudinal direction; no yielding 

45,000 lbf (200 kN) at the AT plate; lateral direction; no yielding 

Longitudinal load at 18 in. (457 mm) above the underframe; deformation of at least 

one times the depth of the post 

Only a few of the collision and corner post results are described here as examples of the finite 

element calculations. Figure 16 shows part of the model used in the analysis. Approximately 20 

ft. (6.1 m) of the vehicle length was simulated in these calculations. The back (inboard) end of 

this model was fixed against all degrees of freedom in the analyses. The load was applied as a 

line load for all of the linear elastic cases. For the nonlinear cases, which include determination 

of ultimate strength and deformation capacity, the load was applied to the post through an 

‘indenter’ that had a 3-inch (76-mm) radius at the point of contact, was 6 in. (152 mm) high and 

spanned the entire width of the post. This shape was chosen because it facilitates the contact 

modeling; there is, to the authors’ knowledge, currently no standard or recommended practice for 

the geometry of such a loading device. 

Figure 17 shows the load-load point displacement plot for the case in which a load is applied to 

the collision post in the longitudinal direction at 30 in. (762 mm) above the underframe. Note 

that the maximum predicted strength is about 250x103 lbf (1,120 kN), well in excess of the 

required 200x103

 lbf (890 kN) requirement. Figure 18 shows a deformed geometry plot from the 

finite element analysis. The collision post has been deformed 7.75 in. (197 mm), a value equal 

to the depth of the post. Figure 19 shows a plot of the equivalent plastic strain as a measure of 

the likelihood of fracture. Note that the strains at the lower connection, which is the most highly 

strained connection in this case, are less than 25 percent. Typical elongation values for the A710 

material exceed 30 percent. This indicates that significant cracking is unlikely to occur for a 

deformation equal to one times the depth of the post. 

30 
200 

150 

Depth of 

Collision Post 

100 

0 

0 2 4 6 8 10 12 1

Load Point Displacement (inches) 

Force (103 lbf) 

50 

Figure 16. Model Used to Assess Various Load Cases for the SOA End Frame Design 

250 

4 

Figure 17. Calculated Load-Load Point Displacement Plot for a Longitudinal Load 

Applied on the Collision Post 30 in. (762 mm) above the Floor (Load is for One Post) 

31 
Figure 18. Deformed Model Corresponding to a Load Point Displacement of 7.75 in. (197 

mm) on the Collision Post 

PEEQ = 0.225-0.250 

Figure 19. Equivalent Plastic Surface Strain Contours Corresponding to a Load Point 

Displacement of 7.75 in. (197 mm) on the Collision Post 

32 
250 

200 

150 

100 

50 

0 

0 2 4 6 8 10 12

Load Point Displacement (inches) 

Depth of 

Collision Post 

Force (103 lbf) 

Figure 20 shows the load-load point displacement plot for the case in which a load is applied to 

the corner post in the longitudinal direction at 18 in. (457 mm) above the underframe. In this 

case the maximum predicted strength is approximately 230x103 lbf (1,023 kN). A strength 

comparable to that obtained for the collision post, represented in Figure 17, is explained by the 

fact that the corner post is loaded at about one-half the height as the collision post and the 

strength requirement for a load above the underframe is based on a yield criterion for the corner 

post rather than the ultimate strength criterion for the collision post. There is no requirement for 

the ultimate strength of the corner post for a load applied at 18 in. (457 mm). However, there is 

a requirement for deformation. Figure 21 shows a plot of the deformed geometry, and Figure 22 

shows a plot of the equivalent plastic strain on the post surface corresponding to a load point 

displacement of 6 in. (152 mm), the depth of the corner post. The bulkhead has been removed 

from the figure for clarity. Here, there is a small area over which the plastic strain exceeds the 

nominal 30 percent elongation of the A710 material. This indicates that some cracking could 

occur for a deformation equal to one times the depth of the post. However, it is unlikely that the 

integrity of the corner post – end/buffer beam connection is significantly compromised. For 

ultimate load conditions, it is expected that some cracking of material may occur. 

14 

Figure 20. Load-Load Point Displacement Plot for a Longitudinal Load Applied on the 

Corner Post 18 in. (457 mm) above the Floor 

33 
Figure 21. Deformed Model Corresponding to a Load Point Displacement of 6 in. on the 

Corner Post at 18 in. (457 mm) above the Floor

0.30<PEEQ<0.45 

Figure 22. Equivalent Plastic Surface Strain Contours Corresponding to a Load Point 

Displacement of 6 in. (152 mm) on the Corner Post 

34 
Figure 23 shows the stress contour plot for the load case in which 100x103

 lbf (445 kN) is 

applied to the corner post in the transverse direction 18 in. (457 mm) above the underframe. 

Only some of the structural components are shown in the half-model in the figure: the end beam, 

the collision and corner posts, the shelf, the bulkhead, the AT plate, the side sill and the roof 

member. The draft sill, in which stresses are well below yield, is removed for clarity. The Mises 

(effective) stress is plotted for the surface of the structural components. The results show that 

there are no stresses greater than 75x103 psi (517 MPa) the minimum required yield strength of 

the A710 material used, except at the point of load application. Very small localized areas of 

plasticity at the load point locations can occur without affecting the global performance of the 

system and are therefore acceptable. 

Figure 23. Mises Surface Stress Contour Plot for the 100x103

 lbf (445 kN) Lateral Corner 

Post Load at 18 in. (457 mm) 

35 
36 
6. Fabrication 

Ebenezer Railcar Services, West Seneca, New York, fabricated the end frames and then shipped 

them to the TTC in Pueblo, Colorado, for integration into the existing cars. The general 

sequence of fabrication was as follows: 

1. Plate pieces were ordered from the material vendor 

2. Pieces requiring it were then beveled and formed into the required shape 

3. The pieces were then welded together 

4. Inspection was carried out throughout the fabrication process. 

The primary material of construction, A710, was selected because it is now commonly used in 

the construction of rail vehicles for North American operation. The material was obtained from 

a few different heats, each with slightly different mechanical properties. Table 6 lists typical 

values for the primary material based on the different heats and thicknesses. 

Table 6. Average Mechanical Properties for the A710, Gr. A, Class 3 Steel Used to 

Fabricate the 1990s and SOA Endframes 

Property Average Value 

Yield Strength 87x103 psi (600 MPa) 

Tensile Strength 93x103 psi (640 MPa) 

Elongation (in 2 in. or 51 mm) 30 percent 

The minimum required strengths for this material are: 75x103 psi (517 MPa) for the yield 

strength; and 85x103 psi (586 MPa) for the tensile strength. The minimum elongation (in 2 in. or 

51 mm) is 20 percent. The values for the material used to fabricate the end frames are 

significantly greater than what is probably used in the rail vehicle industry (except for 

elongation). However, a source of material was not found with properties that were closer to the 

minimum required values in the quantities and for the schedule needed. The minimum 

properties were used in the design calculations. 

Welding was carried out using the MIG process following the requirements of AWS D1.1. 

Figures 24 and 25 show photographs of one of the end frames during fabrication. These figures 

show part of the internal structure of the end beam and the AT plate. The completed end frames 

were shown in Figures 7 and 12 in Section 4 on Design Descriptions. 

As part of the fabrication process, parts were inspected prior to all operations. Material 

certifications were also obtained to ensure that minimum properties were met. Measurements 

were also made of the end frames after fabrication. As stated earlier, the integration of the end 

frames onto the existing rail vehicles was carried out by TTC staff. However, the authors of this 

report comprehensively inspected the end frames after integration. 

37 
Figure 24. SOA End Frame in Fabrication; This is the End Beam Before the Top Plate was 

Welded on 

Figure 25. SOA End Frame in Fabrication; This is the AT plate Before the Top Plate was 

Welded on 

38 
7. Static Testing Results: Comparison With Analysis 

Both the 1990s and SOA end frames were extensively instrumented with strain gages and 

subjected to a set of static loads at TTC. This section provides a brief description of the static 

test procedure and reports the agreement between the finite element analyses and test results for 

the two end frame designs and three load cases. 

Approximately 90 strain gages were applied to each end frame and its supporting structure for 

the tests. The locations of many of the gages are shown schematically in Figure 26 and included: 

• Both the front and rear surfaces on the corner post that was to be loaded were strain 

gaged at three locations along its length. 

• Both the front and rear surfaces on the collision post that was to be loaded were strain 

gaged at three locations along its length. 

• The front and rear faces of the AT plate were strain gaged at three locations along its 

width on the side that was to be loaded. 

• The front and rear surfaces of the lateral shelf at three locations along its width on the 

side that was to be loaded. 

• The front and rear surfaces of the end beam at two locations along its width on the side 

that was to be loaded. 

• Three locations along the length of the draft sill on both sides. 

• Three locations along the length of the roof (cant) rail and on the inside and outside 

surfaces between the vestibule and the end frame. 

Three of the test loads applied are listed below and shown schematically in Figure 27. Each was 

applied to the right side of the end frame for an observer looking at the end of the car from the 

outside. 

• A longitudinal load applied 30 in. (762 mm) above the floor on the front of the collision 

post in the inward direction. This load was equal to 100x103

 lbf (445 kN) for both the 

1990s and the SOA end frames. 

• A longitudinal load applied 18 in. (457 mm) above the floor on the front of the corner 

post in the inward direction. This load was 30x103 lbf (133 kN) for the 1990s end frame, 

and 100x103

 lbf (445 kN) for the SOA end frame. 

• A lateral load applied 18 in. (457 mm) above the floor on the side of the corner post in 

the inward direction. Again, this load was 30x103

 lbf (133 kN) for the 1990s end frame, 

and 100x103

 lbf (445 kN) for the SOA end frame. 

The load was applied through a loading ram and load cell in series. Figure 26 shows an example 

for the collision post loading. The load was applied quasi-statically and the car was reacted at 

the opposite end through the coupler, for the case of longitudinal loads, and by a symmetric 

structural support for the case of the lateral load. The loads were applied over an area on a 

square bearing plate with an edge length equal to the width of the post. It is important to apply 

39 
the loads over a minimum area to prevent excessive localized yielding or crimping of the posts 

webs. 

Figure 26. End Frame Quasi-static Loading Test Arrangement; Strain Gage Locations are 

Shown by the Small Colored Points 

40 
Figure 27. Static Loads Applied to the End Frames 

In the analysis, the load was applied to the post through an ‘indenter’ that had a 3-inch (76-mm) 

radius at the point of contact, was 6 in. (152 mm) high and spanned the entire width of the post. 

Strains were interpolated from the analysis to correspond to the reported locations of the center 

of the gages. 

Figures 28-33 show examples of strain comparisons between test and finite element analysis for 

a set of load cases and locations. The individual measurement and analysis results are provided 

in Appendix E. The analysis results agree well with the test measurements, particularly when the 

strain magnitudes are relatively large. 

Review of the data in Appendix E shows that there is some disagreement in results for the draft 

sill and roof rail locations. In part, these strains are relatively low and poorer agreement is 

expected. In addition, the details of the car structure to which the end frame was attached were 

not characterized in detail and so there are likely differences between the actual test geometry 

and the geometry simulated in the model. 

41 
100,000 lbf Longitudinal Load on the Collision Post 30 Inches Above Floor

Collision Post Strains: Middle of Post

SOA End Frame

-1500 

-1000 

-500 

0 

500 

1000 

1500 

2000 

Strain (με) 

Experimental Strain 

Analysis Strain 

Post Middle: Left Front Post Middle: Left Rear Post Middle: Right Front Post Middle: Right Rear 

Location 

100,000 lbf Longitudinal Load on the Collision Post 30 Inches Above Floor

Lateral Shelf Strains: Left Side

SOA End Frame

1200 

1000

800

600

Shelf Left: Bottom Front Shelf Left: Top Front Shelf Left: Bottom Rear Shelf Left: Top Rear 

Location 

Experimental Strain 

Analysis Strain 

Strain (με) 

400 

200 

0 

-200 

-400 

-600 

Figure 28. Comparison of Test to Analysis Results for the SOA Collision Post Loading 

Case: Strains at the Middle (Vertically) of the Collision Post 

Figure 29. Comparison of Test to Analysis Results for the SOA Collision Post Loading 

Case: Strains at the Left-Hand (Collision Post) Side of the Lateral Shelf 

42 
100,000 lbf Longitudinal Load on the Corner Post 18 Inches Above the Floor

Corner Post Strains: Top of Post

SOA End Frame

-500 

-400 

-300 

-200 

-100 

0 

100 

200 

300 

400 

Strain (με) 

Experimental Strain 

Analysis Strain 

Post Top: Left Front Post Top: Left Rear Post Top: Right Front Post Top: Right Rear 

Location 

Figure 30. Comparison of Test to Analysis Results for the SOA Corner Post Loading Case: 

Strains at the Top of the Corner Post 

100,000 lbf Longitudinal Load on the Collision Post 30 Inches Above the Floor

Collision Post Strains: Bottom of Post

1990s Design

-1000 

-800 

-600 

-400 

-200 

0 

200 

400 

600 

800 

1000 

Strain (με) 

Experimental Strain 

Analysis Strain 

Post Bottom: Left Post Bottom: Left Rear Post Bottom: Right Post Bottom: Right 

Front Front Rear 

Location 

Figure 31. Comparison of Test to Analysis Results for the 1990s Collision Post Loading 

Case: Strains at the Bottom of the Collision Post 

43 
30,000 lbf Longitudinal Load on the Corner Post 18 Inches Above the Floor

Corner Post Strains: Middle of Post

1990s Design

Post Middle: Left Front Post Middle: Left Rear Post Middle: Right Post Middle: Right Rear 

Front 

Location 

-1500 

-1000 

-500 

0 

500 

1000 

1500 

Strain (με) 

Experimental Strain 

Analysis Strain 

-150 

-100 

-50 

0 

50 

100 

150 

Strain (με) 

Experimental Strain 

Analysis Strain 

AT Plate Right: Bottom AT Plate Right: Bottom AT Plate Right: Top AT Plate Right: Top 

Front Rear Front Rear 

Location 

30,000 lbf Lateral Load on the Corner Post 18 Inches Above the Floor

AT Plate Strains: Right Side

1990s Design

Figure 32. Comparison of Test to Analysis Results for the Lateral Corner Post Loading 

Case: Strains in the Shelf 

Figure 33. Comparison of Test to Analysis Results for the Lateral Corner Post Loading 

Case: Strains in the Shelf (Rear Surface) 

44 
8. Summary 

This report describes the results of a program to design end frames for testing the differences in 

crashworthiness performance for cab cars that meet early to mid 1990s structural standards and 

cab cars designed to the current APTA and FRA structural requirements (SOA design). The 

program is part of a larger one being conducted to investigate how crashworthiness of rail 

vehicles in various configurations and collision scenarios can be improved. The end frames 

discussed here were used to evaluate the increase in cab car protection for a particular grade 

crossing collision scenario. The development of the designs relied on a review of industry 

practice over the last few decades and on prior research in the area of cab car crashworthiness. A 

detailed set of design requirements was developed that included the applicable structural 

requirements, the need to meet operability requirements and the need to adapt to existing test 

cars. Hand and beam element finite element analyses were used to develop the 1990s design, 

while detailed finite element analyses, including large deformation calculations, were carried out 

to develop the SOA design. The end frames were fabricated from A710 steel and shipped to the 

Transportation Test Center in Pueblo, Colorado, where they were attached to existing Budd 

Pioneer cars. Quasi-static loading tests were conducted on the frames after instrumentation by 

strain gages. Finally, the end frames were used in full-scale grade crossing collision tests in a 

separate program. 

The results of this project demonstrate that the new APTA requirements can be met with designs 

that are very similar to those needed to satisfy the requirements used in the 1990s. For example, 

there is only a 250 lbm (113 kg) weight difference between the 1990s and SOA end frame 

designs. In addition, the analyses and the full-scale tests demonstrate that the stronger end 

frames provide a significant improvement in crashworthiness. 

A number of important issues were raised in the course of this program. The SOA design relied 

on the use of the side sill to support the back of the end beam at the base of the corner post. This 

is possible because of the general acceptance by industry to eliminate the step well at the 

operator’s corner. If a step well were present so that such a structural detail could not be used, 

the weight penalty would be much greater [11]. 

The ability to achieve a prescribed amount of deformation in the end frame posts has also been 

raised as an important issue. The SOA design was developed with the requirement that the post 

deform an amount equal to one times its depth for a load applied at 30 in. (762 mm) above the 

underframe (for the collision post) and 18 in. (457 mm) above the underframe (for the corner 

post) without cracking. This requirement was originally under discussion within APTA but 

eventually was not adopted. Instead, deformability is achieved in an indirect manner by 

requiring very strong connections between the posts and the end beam and the AT plate. In other 

words, the design can still be developed by considering only strength-based criteria. The concept 

of addressing energy absorption directly remains a topic of discussion. 

The very successful performance of the SOA design in the full-scale test relative to the 1990s 

end frame demonstrates the potential for crashworthiness improvement [9,10]. 

45 
46 
References 

1. National Transportation Safety Board, Railroad Accident Report: Collision of Illinois 

Central Gulf Railroad Commuter Trains, Chicago, Illinois, October 30, 1972. NTSB-RAR73-5. Washington, DC. 1973. 

2. National Transportation Safety Board, Railroad Accident Report: Collision of Northern 

Indiana Commuter Transportation District Train 102 with a Tractor-Trailer Portage, 

Indiana June 18, 1998. NTSB-RAR-99-03. Washington, DC. 1999. 

3. National Transportation Safety Board, Railroad Accident Report: Railroad Accident Report 

Near Head-on Collision and Derailment of Two New Jersey Transit Commuter Trains Near 

Seacaucus, New Jersey February 9, 1996. NTSB-RAR-97-01. Washington, DC. 1997. 

4. Stringfellow, R., Mayville, R., Rancatore, R., “Evaluation of Protection Strategies for Cab 

Car Crashworthiness,” ADL Report Reference 30299-05 (January 2000) 38 pages. 

5. Mayville, R.A., Hammond, R.P. and Johnson, K.N., “Static and Dynamic Crush Testing and 

Analysis of a Rail Vehicle Corner Structural Element,” in AMD-Vol. 237/BED-Vol. 45, 

Crashworthiness, Occupant Protection and Biomechanics in Transportation Systems, (1999) 

51-67. 

6. Tyrell, D.C., Severson, K.J., Mayville, R.A., Stringfellow, R.G., Berry, S. and Perlman, A., 

“Evaluation of Cab Car Crashworthiness Design Modifications,” in Proceedings of the 1997 

IEEE/ASME Joint Railroad Conference, March 18-20, 1997, Boston, MA (1997) 49-58. 

7. APTA SS-C&S-034-99, Standard for the Design and Construction of Passenger Railroad 

Rolling Stock, The American Public Transportation Association, Washington, DC. 

8. Code of Federal Regulations, Title 49, Part 238, various sections (last revised October 1, 

2000.). 

9. Martinez, E., Tyrell, D. and Zolock, J., “Rail-Car Impact Tests with Steel Coil: Car Crush,” 

in Proceedings of ASME/IEEE Joint Railroad Conference, April 22-24, 2003, Chicago, IL 

(2003) 10 pages. 

10. Jacobsen, K., Tyrell, D. and Perlman, B., “Rail Car Impact Tests with Steel Coil: Collision 

Dynamics,” in Proceedings of ASME/IEEE Joint Railroad Conference, April 22-24, 2003, 

Chicago, IL (2003) 10 pages. 

11. Mayville, R.A., Rancatore, R.J., Tegler, L., “Investigation and Simulation of Lateral 

Buckling in Trains,” Proceedings of the 1999 ASME/IEEE Joint Railroad Conference, 

Institute of Electrical and Electronics Engineers, Catalog Number 99CH36340, 1999. 

47 

Acronyms 

AAR American Association of Railroads 

APTA American Public Transportation Association 

AT Anti-Telescoping 

CFR Code of Federal Regulations 

FRA Federal Railroad Administration 

MBTA Massachusetts Bay Transportation Authority 

SOA State-of-the-Art 

SS-C&S Safety Standards-Construction/Structural (APTA) 

TTC Transportation Technology Center 

49 

Appendix A. Examples of Single Level Cab Cars 

Table A-1. Examples of Single Level Cab Cars 

Owner, 

Service 

Area 

Manufacturer 

Car Series 

Delivery 

Date 

Quantity: 

Cabs (C) 

No cab (N) 

Comments 

MARC 

BaltimoreWashington 

Nippon 

Sharyo 

1991/2 6 C 

28 N 

Cars operate at up to 110mph on Northeast Corridor 

with cab leading 

MBTA 

Boston 

Bombardier 1989/90 53 C 

54 N 

Ex-Pullman aluminum body car design. End doors 

with stairwell 

NICTD 

Chicago 

Sumitomo 1992 7 C 

10 N 

Electric MU cars. Cab cars have two cabs. End 

doors with stairwell 

NICTD 

Chicago 

Nippon Sharyo 2000-01 10C Electric MU cars. All cars have cabs End doors 

with stairwell 

Connecticut 

DOT 

New Haven 

Bombardier 1991 10 C Ex Pullman aluminum design, 2 cabs, end doors 

with stairwell 

MNCR 

New York 

Bombardier 1991-9 58 C 

95N 

Ex Pullman aluminum design. Most have end doors 

with stairwell plus a floor-height center door. 

MNCR 

New York 

Morrison 

Knudsen 

M6 

1995-6 60 C Electric MU cars with 2 sets of center doors and no 

stairwells for high platform operation 

NJT 

Northern 

New Jersey 

Bomb 

Comet III/IV 

1990-97 31 C 

119 N 

Ex-Pullman aluminum design. End doors with 

stairwell 

NJT 

Northern 

New Jersey 

Alstom 

Comet V 

2001-3 200 Total 

130 Firm, 

incl 50 C 

New design, probably with stairwells at non-cab 

ends. Required to be compliant with new 

FRA/APTA requirements 

SEPTA 

Philadelphia 

Bombardier 1999-

2000 

10 N Ex-Pullman aluminum design. End doors with 

stairwell. 

VRE 

Washington 

Morrison 

Knudsen 

1992 10 C 

28 N 

Have end doors with stairwells 

VRE 

Washington 

Kawasaki 1999 4 C 

9 N 

End doors with stairwell 

Amtrak Morrison 

Knudsen 

view-liners 

1993-4 51 N All sleepers for eastern routes. Door with stairwell 

at one end of car only. No cab cars 

LIRR/ 

MNCR 

New York 

Bombardier 

M7 

2001 on Up to 808 

326 firm 

for LIRR 

New design of electric MU car for high-level 

platforms. No stairwells. Originally ordered May 

1999, before new FRA/APTA regulations 

51 
52 
Appendix B. Requirements for the Cab Car End Frames 

B-1. Introduction 

B-1.1. Purpose 

The purpose of this specification is to define the requirements for the rail passenger cab car 

end structures to be fabricated onto an existing rail vehicle. 

B-1.2. Definitions 

B-1.2.1. Budd Pioneer Car 

The vehicles to which the designs of this project must be adapted. These vehicles were used 

in the first two full-scale collision tests at TTCI in Pueblo, Colorado. The vehicles conform 

to the design defined by the drawings in Appendix A. 

B-1.2.2. Permanent deformation 

There is technically no permanent deformation if a stress analysis shows that the Mises stress 

does not exceed the minimum specified yield strength. 

B-2. Reference Documents/Drawings 

B-2.1. Budd Pioneer Drawings 

See attached list, Appendix A. 

B-2.2. Standards 

B-2.2.1. AWS D1.1 

B-2.2.2. APTA SS-C&S-034-99, Standard for the Design and Construction of 

Passenger Railroad Rolling Stock, The American Public Transportation Association, 

Washington, D.C. 

B-2.2.3. Code of Federal Regulations, Title 49, Part 238, Various Sections (Last Revised 

October 1, 2003.) 

B-2.2.4. AAR-S-034, Specifications for the Construction of New Passenger Equipment 

Cars, The Association of American Railroads, Last Revised, 1969. 

53 
B-3. General Description 

The cab car end structures, whose specifications are outlined in this document, are for use in 

full-scale tests to be conducted in late 2001. These tests will be used to investigate the 

collision performance of cab cars in simulated grade crossing collisions. One design will 

emulate a structure typical of those cab cars designed in the 1990s timeframe; the other design 

will emulate cab car end structures that satisfy the most recent, ‘State-of-the-Art’ (SOA) 

designs as defined, for example by the APTA SS-C&S-034-99 standard. The cab cars 

equipped with these end structure designs will be tested either alone or in a consist representing 

a commuter train. The cab car will collide with some type of object intended to simulate an 

object in a grade crossing. The most likely such object, as of this writing, is a steel coil whose 

center of mass is offset laterally from the centerline of the vehicle at the instant of collision. 

The cars must also satisfy certain operational requirements in addition to the strength 

characteristics so that they could be used (mechanically) in actual service if incorporated into a 

modern rail coach car. 

The requirements listed here are derived from two sources: (1) actual car requirements from 

operating companies; and (2) industry and federal requirements. The former is, in part, 

represented by the specifications for the Bombardier MBTA single level cars that have been in 

operation in the 1990s. The latter requirements are partly contained in APTA SS-C&S-034-99, 

Standard for the Design and Construction of Passenger Railroad Rolling Stock and its 

predecessor, AAR S-034, and the Code of Federal Regulations, Title 49, Part 238. 

B-4. Specific Requirements 

The requirements are divided into three major sections: 

• Requirements specific to the 1990s design (Section 4.1) 

• Requirements specific to the State-of-the-Art (SOA) design (Section 4.2) 

• Requirements common to both designs (Section 4.3) 

B-4.1. 1990s Design Requirements 

B-4.1.1. Coupler Carrier 

The coupler carrier shall be capable of resisting a downward force applied to the coupler 

shank of 100x103

 lbf (445 kN), for any position of the coupler, without permanent 

deformation. 

B-4.1.2. Coupler 

The coupler and its supporting structure shall be capable of resisting an upward force of 

100x103 lbf (445 kN) without permanent deformation. 

54 
B-4.1.3. End Strength 

The strength of the vehicle end shall be at least 800x103 lbf (3,560 kN) without permanent 

deformation. This load shall be applied to the rear draft stops ahead of the bolster on the 

centerline of draft. 

B-4.1.4. Collision Posts 

B-4.1.4.1. Description 

There shall be two full height collision posts extending from the underframe to the cant rail 

or roofline. They shall be located at the approximate 1/3 points across the width of the 

vehicle and shall, in their entirety, be forward of the seating position of any crew person. 

B-4.1.4.2. Strength 

The collision post shall resist each one of the following horizontal inward loads 

individually applied at any angle within 15 degrees of the longitudinal axis: 

a) Minimum 300x103 lbf (1,330 kN) applied at a point even with the top of the 

underframe, without exceeding the ultimate shear strength of the post. 

b) Minimum 300x103 lbf (1,330 kN) applied at a point 18 in. (457 mm) above the top of 

the underframe, without exceeding the ultimate strength. 

Any reinforcement required to provide the specified 300x103 lbf (1,330 kN) shear strength 

at the top of the underframe, shall extend with its full section from the bottom of the end 

sill to a distance of 18 in. (457 mm). The reinforcement must then taper to a point 

approximately 30 in. (762 mm) above the top of the underframe. In addition, the 

connection of the post to the anti-telescoping plate/roof structure shall have sufficient 

ultimate strength to sustain loads produced by bending the collision post to its ultimate 

strength. Each collision post and any shear reinforcement, if used, shall be welded to the 

top and bottom plates of the end sill with the equivalent of AWS pre-qualified welded 

joints. 

B-4.1.5. Corner Posts 

B-4.1.5.1. Description 

The vehicle end shall have two structural corner posts, one located at each extreme corner 

of the car body structure. The corner posts shall extend from the bottom of the underframe 

structure to the bottom of the roof structure. 

B-4.1.5.2. Strength 

Each corner post and intervening connections shall resist each of the following horizontal 

loads individually applied toward the inside of the vehicle in any direction from 

longitudinal to transverse: 

a) Minimum 150x103

 lbf (667 kN) applied at a point even with the top of the underframe, 

without exceeding the ultimate shear strength of the post. 

55 
b) Minimum 30x103

 lbf (133 kN) applied at a point 18 in. (457 mm) above the top of the 

underframe, without permanent deformation. 

In addition, the connection of the post to the anti-telescoping plate/roof structure shall have 

sufficient ultimate strength to sustain loads produced by bending the corner post to its 

ultimate strength. 

B-4.1.6. Horizontal Framing Members 

B-4.1.6.1. Description 

There shall be a horizontal structural member between the collision post and the corner 

post at a height equivalent to the bottom of the windshield. 

B-4.1.6.2. Strength 

The horizontal member shall be capable of carrying a longitudinally oriented load of 

15x103 lbf (66.7 kN) anywhere along its length without causing permanent deformation. 

B-4.1.7. Stepwell 

The vehicle end shall include space for a stepwell. However, an actual stepwell need not 

be included. 

B-4.2. State-of-the-Art Design Requirements 

B-4.2.1. Coupler Carrier 

The coupler carrier shall be capable of resisting a downward force applied to the coupler 

shank of 100x103 lbf (445 kN) without permanent deformation. 

B-4.2.2. Coupler 

The coupler and its supporting structure shall be capable of resisting an upward force of 

100x103

 lbf (445 kN) without permanent deformation. 

B-4.2.3. End Strength 

The strength of the vehicle end shall be at least 800x103 lbf (3,560 kN) without permanent 

deformation. This load shall be applied longitudinally over an area not exceeding 6-in. (152 

mm) high and a width not exceeding the distance between outboard webs of the collision 

posts, centered vertically and horizontally on the underframe end sill or end beam 

construction. 

B-4.2.4. Collision Posts 

B-4.2.4.1. Description 

There shall be two full height collision posts extending from the underframe to the cant rail 

or roofline. They shall be located at the approximate 1/3 points across the width of the 

vehicle and shall, in their entirety, be forward of the seating position of any crew person. 

B-4.2.4.2. Strength 

56 
The collision post shall resist each one of the following horizontal inward loads 

individually applied at any angle within 15 degrees of the longitudinal axis: 

a) Minimum 500x103 lbf (2,224 kN) applied at a point even with the top of the 

underframe, without exceeding the ultimate shear strength of the post. 

b) Minimum 200x103 lbf (890 kN) applied at a point 30 in. (762 mm) above the top of 

the underframe, without exceeding the ultimate strength. 

c) Minimum 60x103 (267 kN) applied at any height along the post above the top of the 

underframe, without permanent deformation. 

The area properties of the collision posts, including any reinforcement required to provide 

the specified 500x103 lbf (2,224 kN) shear strength at the top of the underframe, shall 

extend from the bottom of the end sill to at least 30 in. (762 mm) above the top of the 

underframe. Each collision post and any shear reinforcement, if used, shall be welded to 

the top and bottom plates of the end sill with the equivalent of AWS pre-qualified welded 

joints. 

The collision post and its supporting structure shall be designed so that if overloaded at a 

point 30 in. (762 mm) above the underframe, failure shall begin as bending or buckling in 

the post. The connections of the post to the supporting structure, and the supporting car 

body structure, shall support the post at its ultimate capacity. The ultimate shear and 

tensile strength of the connecting fasteners or welds shall be sufficient to resist the forces 

causing the deformation, so that shear and tensile failure of the fasteners or welds shall not 

occur, even with ‘severe deformation’ of the collision post and its connecting and 

supporting structural elements. For purposes of design, severe deformation shall mean the 

depth of the post of inward deformation at 30 in. (762 mm) above the underframe. 

B-4.2.5. Corner Posts 

B-4.2.5.1. Description 

The end structure shall have two structural corner posts, one located at each extreme corner 

of the car body structure. The corner posts shall extend from the bottom of the underframe 

structure to the bottom of the roof structure. 

B-4.2.5.2. Strength 

Each corner post and intervening connections shall resist each of the following horizontal 

loads individually applied toward the inside of the vehicle in any direction from 

longitudinal to transverse: 

a) Minimum 300x103

 lbf (1,330 kN) applied at a point even with the top of the 

underframe, without exceeding the ultimate shear strength of the post. 

b) Minimum 100x103

 lbf (445 kN) applied at a point 18 in. (457 mm) above the top of 

the underframe, without permanent deformation. 

c) Minimum 45x103 lbf (200 kN) applied anywhere between the top of the post at its 

connection to the roof structure, and the top of the underframe, without permanent 

deformation. 

57 
The area properties of the corner posts, including any reinforcement required to provide the 

specified 300x103 pound (1,330 kN) shear strength at the top of the underframe, shall 

extend from the bottom of the end sill to at least 30 in. (762 mm) above the top of the 

underframe. Each corner post and any shear reinforcement, if used, shall be welded to the 

top and bottom plates of the end sill with the equivalent of AWS pre-qualified welded 

joints. 

The corner post and its supporting structure shall be designed so that if overloaded at a 

point 30 in. (762 mm) above the underframe, failure shall begin as bending or buckling in 

the post. The connections of the post to the supporting structure, and the supporting car 

body structure, shall support the post at its ultimate capacity. The ultimate shear and 

tensile strength of the connecting fasteners or welds shall be sufficient to resist the forces 

causing the deformation, so that shear and tensile failure of the fasteners or welds shall not 

occur, even with ‘severe deformation’ of the collision post and its connecting and 

supporting structural elements. For purposes of design, severe deformation shall mean the 

depth of the post of longitudinal, inward deformation at 30 in. (762 mm) above the 

underframe. 

B-4.2.6. Horizontal Framing Members 

B-4.2.6.1. Description 

There shall be a horizontal structural member between the collision post and the corner 

post at a height equivalent to the bottom of the windshield. 

B-4.2.6.2. Strength 

The horizontal member shall be capable of carrying a longitudinally oriented load of 

15x103 lbf (66.7 kN) anywhere along its length without causing permanent deformation. 

B-4.2.7. Stepwell 

The vehicle end shall not include space for a stepwell. 

B-4.3. Operational Requirements (Both Designs) 

B-4.3.1. Coupler System 

B-4.3.1.1. Coupler 

The coupler shall be a Type H tightlock coupler. There is no specific requirement on shank 

length except that it must be compatible with the other requirements of this specification. 

B-4.3.1.2. Coupler Carrier 

A coupler carrier must be provide that includes a spring loaded device to ensure that the 

coupler remains level during normal use. 

B-4.3.1.3. Draft Gear 

The coupling system shall include a draft gear capable of absorbing low speed impacts. 

58 
B-4.3.1.3.1. General 

The coupling system shall include a draft gear capable of absorbing low speed impacts. 

B-4.3.2. Uncoupling 

The vehicle end shall be equipped with an AAR Style No.6 uncoupling mechanism. 

B-4.4. Test Requirements 

B-4.4.1. General 

The vehicle ends designed and built to this specification will be used for full-scale testing. 

Therefore, it is important that the design facilitate measurements and observations to be made 

during the tests. The types of tests envisioned include: 

a) a single vehicle colliding with an object representing a grade crossing obstacle; 

b) a multiple vehicle consist colliding with the rigid surface; and 

c) a multiple vehicle consist colliding with a grade crossing obstacle. 

The tests will be conducted at TTC in Pueblo, Colorado. 

B-4.4.2. Visibility 

The vehicle end shall be designed in such a way that it will be possible to view the collision 

and corner posts during crush deformation in the test. For example, parts of the roof and 

sides must remain open to facilitate viewing by cameras mounted on the ground or on the 

vehicle. 

B-4.5. Fabrication Requirements 

B-4.5.1. General 

The design should utilize materials and fabrication methods that a normal metal fabrication 

company could use. 

B-4.5.2. Materials and Construction Methods 

B-4.5.2.1. Materials 

The materials of construction for the primary structure shall be either high strength low 

alloy (also known as low-alloy, high tensile) or austenitic stainless steels commonly used in 

the fabrication of modern railway vehicles for operation in North America. The energy 

absorbing elements shall be constructed from either the steels mentioned above and/or 

aluminum honeycomb. 

B-4.5.2.2. Construction Methods 

All primary structural members shall be welded in accordance with AWS D1.1. 

59 
B-4.5.2.2.1. Overall vehicle integration. 

The end structure shall be designed so that it can be integrated into the existing Budd 

Pioneer coach cars. The goal of the design shall be to minimize the amount of effort 

required for building the end structures into the existing cars.

B-4.6. Physical Requirements 

B-4.6.1. Envelope 

The end structures are to be attached to the end of one of the existing Budd Pioneer cars. Its 

outer boundaries should not exceed those of the as-built Budd Pioneer cars with the 

possible exception of the length beyond the bolster center point. 

B-4.6.2. Curving 

The components of the vehicle end shall not interfere for operation with nominally 

identical cars operating on curves as tight as a 250-foot (76.2 m) radius. 

B-4.6.3. Space for Normal Equipment 

Although much of the usual equipment found on passenger rail cars will not be included in 

this design, the design shall provide space for this equipment. Openings, piping and other 

equipment normally associated with this equipment need not be included. The equipment 

not already specified includes: 

• Hand brake 

• HEP (head end power) 

• 27-point communication line 

• Trainline box 

• Electronic brake box 

• Diaphragm 

60 
Appendix C. Sections from the Drawings Used to Fabricate the End Frames 

61 
62 
63 

Plan View of the Left Side of the Buffer Beam with Collision and Corner Posts in 

1990s Design

63 
64 

Side View Section Through the Collision Post and Buffer Beam; 1990s Des

64 
65 

Front Elevation of the State-of-the-Art End Frame

65 
66 

Plan View of the Left Side of the Buffer Beam with Collision and Corner Posts in Secti

State-of-the-Art Design

66 
67 

Section through the Buffer Beam and Collision Post at the Draft Sil

State-of-the-Art Design

67 
68 

Section through the Corner Post and Buffer Beam;

State-of-the-Art Design

68 
69 

Section through the Collision Post/AT Plate;

State-of-the-Art Design

69 
70 

Section through the Lateral Shelf and Bulkhead;

State-of-the-Art Design

70 
71 

Section of the Side Sill between the Buffer Beam and Bolster;

State-of-the-Art Design

71 
72 
Appendix D. Example Calculation for Collision Post Strength 

This section provides an example of one of the hand calculation procedures used in the design of 

the end frames. It is for the case in which the collision post must possess an ultimate strength for 

a longitudinal load applied at and above the underframe. The example given here is for the SOA 

design for which the collision post must possess an ultimate strength of 500x103

 lbf (2,224 kN) 

for a longitudinal load applied at the underframe, and 200x103

 lbf (890 kN) for a longitudinal 

load applied 30 in. (762 mm) above the underframe. 

The 500,000 lbf shear load determines the area of the webs of the post: 

Fu Fu 500,000 2 A w ≥ = = = 9.58in

τ u 0.58σ u 0.58(90,000)

where Aw is the area of the webs 

Fu is the ultimate load 

τu is the ultimate strength in shear of the post and lug material 

σu is the ultimate tensile strength of the post and lug material. 

The collision post cross section is shown in Figure D-1. The area of the webs in this case is: 

2 Aw = 2[(0.375)(7.75) + (0.375)(5.125)] = 9.66in , 

which is greater than the required area. 

The ultimate strength for a load applied at 30 in. (762 mm) above the underframe is, by the 

requirements, to be determined by a plastic collapse bending mechanism. For this particular 

geometry and loading, the first plastic hinge in the post forms at the underframe. Plastic collapse 

then occurs when a hinge forms at the load point; the attachment to the AT plate is assumed to 

behave as simply supported for the entire loading. 

The ultimate strength in this case can be determined by the equilibrium method of plastic limit 

load analysis (c.f. [D1]) The beam is assumed to be in equilibrium at the point that a mechanism 

is formed for which the bending moment at the hinges is equal to the plastic moment. (In the 

collision post case the hinge at the AT plate is taken as a true hinge.) Then the plastic moment 

required to balance the applied load is given by: 

l1l M 2

p = Pu l + l2 

where, l1 = the distance from the applied load to the plastic hinge at the support 

73 
l2 = the distance from the applied load to the true hinge 

l = l1 + l2

Pu = the applied load. 

In the present case then, the required plastic moment is: 

M p = (30)(45.56) (200,000) = 2.26x106 in − lbf . 75.56 + 45.56 

The plastic moment for the collision post section with lugs, which extend to 45 in. (1140 mm) 

above the underframe, is 2.28x106

 in-lbf (257x103 N-m). 

Figure D-1. The SOA Collision Post Cross Section 

Reference 

1. Steel Structures; Design and Behavior, 3rd Edition (HarpersCollins)1990. 

74 
Appendix E. Tables of Strains from Test Measurements and Finite 

Element Analysis 

(See Section 7 of the main text for a description of the strain gage locations.) 

75 
76 
Table E-1. 1990s Design: 30,000 lbf (9,140 N) Longitudinal Load on Corner Post, 

18 In. Above Floor 

Component Location 

Forward Surface Rear Surface 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Bottom Left SG-COR-BFL 455 265 SG-COR-BRL -308 -389 

Bottom Right SG-COR-BFR -227 -281 SG-CORBRR 262 257 

Corner Post 

(Vertical) 

Middle Left SG-COR-MFL -933 -987 SG-CORMRL 914 965 

Middle Right SG-CORMFR -1040 -961 SG-CORMRR 1042 954 

Top Left SG-COR-TFL 551 302 SG-COR-TRL -636 -313 

Top Right SG-COR-TFR -66 -71 SG-CORTRR -268 -518 

Bottom Left SG-COL-BFL -203 -97 SG-COL-BRL 160 78 

Bottom Right SG-COL-BFR -214 -171 SG-COL-BRR 221 169 

Collision Post 

(Vertical) 

Middle Left SG-COL-MFL -232 -184 SG-COL-MRL 234 183 

Middle Right SG-COL-MFR -226 -176 SG-COLMRR 227 160 

Top Left SG-COL-TFL -6 -1 SG-COL-TRL 11 -2 

Top Right SG-COL-TFR -15 -26 SG-COL-TRR 17 23 

Left Top SG-ATP-LFT 0 (failed) -72 SG-ATP-LRT 177 123 

Left Bottom SG-ATP-LFB -166 -107 SG-ATP-LRB 147 95 

AT Plate 

(Lateral) 

Middle Top SG-ATP-MFT -65 -37 SG-ATP-MRT 48 43 

Middle 

Bottom 

SG-ATP-MFB -61 -39 SG-ATP-MRB 82 51 

Right Top SG-ATP-RFT 78 36 SG-ATP-RRT -168 -109 

Right Bottom SG-ATP-RFB -17 9 SG-ATP-RRB 154 -21 

Left Top SG-LM-LFT 973 -279 SG-LM-LRT -1013 333 

Left Bottom SG-LM-LFB 667 -325 SG-LM-LRB -1025 334 

Lateral 

Member/Shelf 

(Lateral) 

Middle Top SG-LM-MFT 192 184 SG-LM-MRT -225 -245 

Middle 

Bottom 

SG-LM-MFB 152 140 SG-LM-MRB -210 -247 

Right Top SG-LM-RFT -613 -399 SG-LM-RRT 632 422 

Right Bottom SG-LM-RFB -444 -394 SG-LM-RRB 571 487 

Center Top SG-BB-CFT 261 248 SG-BB-CBT -229 -217 

End beam 

(Lateral) 

Center 

Bottom 

SG-BB-CFB 261 256 SG-BB-CBB -251 -249 

End Top SG-BB-EFT -4 20 SG-BB-EBT 4 1 

End Bottom SG-BB-EFB 4 5 SG-BB-EBB -4 -3 

Outer Surface Inner Surface 

Component Location 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Top Forward SG-DS-TRF -495 -223 SG-DS-TLF 443 227 

Bottom Fwd. SG-DS-BRF -12 197 SG-DS-BLF 166 -126 

Draft Sill 

(Longitudinal) 

Top Middle SG-DS-TRM -354 -130 SG-DS-TLM 340 171 

Bottom 

Middle 

SG-DS-BRM -112 100 SG-DS-BLM 249 -15 

Top Rear SG-DS-TRR SG-DS-TLR 

Bottom Rear SG-DS-BRR SG-DS-BLR 

Top Forward SG-CR-TRF SG-CR-TLF -160 -87 

Bottom Fwd. SG-CR-BRF SG-CR-BLF -309 -317 

Cant Rail 

(Longitudinal) 

Top Middle SG-CR-TRM SG-CR-TLM -170 -33 

Bottom 

Middle 

SG-CR-BRM SG-CR-BLM -164 -59 

Top Rear SG-CR-TRR SG-CR-TLR 

Bottom Rear SG-CR-BRR SG-CR-BLR 

77 
Table E-2. 1990s Design: 30,000 lbf (9,140 N) Lateral Load on Corner Post, 18 In. 

(460 mm) Above Floor 

Component Location 

Forward Surface Aft Surface 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Bottom Left SG-COR-BFL 125 13 SG-COR-BRL -23 42 

Bottom Right SG-COR-BFR -42 -32 SG-CORBRR -12 -43 

Corner Post 

(Vertical) 

Middle Left SG-COR-MFL -42 -30 SG-CORMRL -29 -45 

Middle Right SG-CORMFR 4 27 SG-CORMRR 23 -35 

Top Left SG-COR-TFL -42 5 SG-COR-TRL 4 5 

Top Right SG-COR-TFR 6 20 SG-CORTRR 96 -85 

Bottom Left SG-COL-BFL -31 -160 SG-COL-BRL -162 -194 

Bottom Right SG-COL-BFR 162 220 SG-COL-BRR 93 224 

Collision Post 

(Vertical) 

Middle Left SG-COL-MFL 129 118 SG-COL-MRL 91 117 

Middle Right SG-COL-MFR -81 -112 SG-COLMRR -145 -132 

Top Left SG-COL-TFL 12 10 SG-COL-TRL 6 -7 

Top Right SG-COL-TFR -14 -3 SG-COL-TRR 27 -5 

Left Top SG-ATP-LFT 0 (failed) -76 SG-ATP-LRT -118 -69 

Left Bottom SG-ATP-LFB 89 28 SG-ATP-LRB 91 43 

AT Plate 

(Lateral) 

Middle Top SG-ATP-MFT -19 -28 SG-ATP-MRT -25 -7 

Middle Bottom SG-ATP-MFB 23 -16 SG-ATP-MRB 15 6 

Right Top SG-ATP-RFT -26 -23 SG-ATP-RRT 55 100 

Right Bottom SG-ATP-RFB 2 -15 SG-ATP-RRB -30 -91 

Left Top SG-LM-LFT -278 90 SG-LM-LRT -318 107 

Lateral 

Member/Shelf 

(Lateral) 

Left Bottom SG-LM-LFB -145 77 SG-LM-LRB -259 109 

Middle Top SG-LM-MFT -350 -337 SG-LM-MRT -375 -291 

Middle Bottom SG-LM-MFB -438 -372 SG-LM-MRB -438 -328 

Right Top SG-LM-RFT -499 -447 SG-LM-RRT -419 -317 

Right Bottom SG-LM-RFB -659 -522 SG-LM-RRB -579 -339 

Center Top SG-BB-CFT -10 -13 SG-BB-CBT -34 -10 

End beam 

(Lateral) 

Center Bottom SG-BB-CFB -29 -38 SG-BB-CBB -50 -22 

End Top SG-BB-EFT -2 -3 SG-BB-EBT 0 -1 

End Bottom SG-BB-EFB 6 4 SG-BB-EBB 6 4 

Outer Surface Inner Surface 

Component Location 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Top Forward SG-DS-TRF -10 -7 SG-DS-TLF -4 -7 

Bottom Fwd. SG-DS-BRF 12 -2 SG-DS-BLF -10 3 

Draft Sill 

(Longitudinal) 

Top Middle SG-DS-TRM 66 -13 SG-DS-TLM -73 12 

Bottom Middle SG-DS-BRM -8 -4 SG-DS-BLM 14 0 

Top Rear SG-DS-TRR SG-DS-TLR 

Bottom Rear SG-DS-BRR SG-DS-BLR 

Top Forward SG-CR-TRF SG-CR-TLF 69 61 

Bottom Fwd. SG-CR-BRF SG-CR-BLF 103 45 

Cant Rail 

(Longitudinal) 

Top Middle SG-CR-TRM SG-CR-TLM 39 32 

Bottom Middle SG-CR-BRM SG-CR-BLM 46 14 

Top Rear SG-CR-TRR SG-CR-TLR 

Bottom Rear SG-CR-BRR SG-CR-BLR 

78 
Table E-3. 1990s Design: 100,000 lbf (30,500 N) Longitudinal Load on Collision 

Post, 30 In. (760 mm) Above Floor 

Component Location 

Forward Surface Aft Surface 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Bottom Left SG-COR-BFL -567 -264 SG-COR-BRL 374 275 

Bottom Right SG-COR-BFR -13 10 SG-CORBRR -13 -3 

Corner Post 

(Vertical) 

Middle Left SG-COR-MFL -446 -355 SG-CORMRL 345 282 

Middle Right SG-CORMFR -354 -296 SG-CORMRR 345 312 

Top Left SG-COR-TFL 139 30 SG-COR-TRL -195 -33 

Top Right SG-COR-TFR -10 14 SG-CORTRR -189 -65 

Bottom Left SG-COL-BFL 462 626 SG-COL-BRL -533 -735 

Bottom Right SG-COL-BFR 578 879 SG-COL-BRR -537 -812 

Collision Post 

(Vertical) 

Middle Left SG-COL-MFL -1432 -1564 SG-COL-MRL 1838 1572 

Middle Right SG-COL-MFR -1573 -1638 SG-COLMRR 1865 1674 

Top Left SG-COL-TFL -50 -64 SG-COL-TRL -55 44 

Top Right SG-COL-TFR -41 -60 SG-COL-TRR -46 27 

Left Top SG-ATP-LFT 0 (failed) -728 SG-ATP-LRT 1147 867 

Left Bottom SG-ATP-LFB -921 -802 SG-ATP-LRB 825 651 

AT Plate 

(Lateral) 

Middle Top SG-ATP-MFT -490 -369 SG-ATP-MRT 499 424 

Middle Bottom SG-ATP-MFB -533 -421 SG-ATP-MRB 509 371 

Right Top SG-ATP-RFT -32 -42 SG-ATP-RRT -40 -2 

Right Bottom SG-ATP-RFB -162 -40 SG-ATP-RRB 255 -146 

Left Top SG-LM-LFT -829 172 SG-LM-LRT 909 -187 

Lateral 

Member/Shelf 

(Lateral) 

Left Bottom SG-LM-LFB -819 168 SG-LM-LRB 800 -204 

Middle Top SG-LM-MFT -194 -115 SG-LM-MRT 211 153 

Middle Bottom SG-LM-MFB -139 -78 SG-LM-MRB 206 163 

Right Top SG-LM-RFT 474 274 SG-LM-RRT -450 -263 

Right Bottom SG-LM-RFB 596 342 SG-LM-RRB -451 -309 

Center Top SG-BB-CFT 59 49 SG-BB-CBT 55 18 

End beam 

(Lateral) 

Center Bottom SG-BB-CFB -95 -52 SG-BB-CBB 48 55 

End Top SG-BB-EFT 0 0 SG-BB-EBT 2 -2 

End Bottom SG-BB-EFB 2 26 SG-BB-EBB 6 3 

Outer Surface-53 Inner Surface 

Component Location 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Top Forward SG-DS-TRF -634 -53 SG-DS-TLF 414 527 

Bottom Fwd. SG-DS-BRF 271 232 SG-DS-BLF 373 -115 

Draft Sill 

(Longitudinal) 

Top Middle SG-DS-TRM -489 -91 SG-DS-TLM 282 272 

Bottom Middle SG-DS-BRM 230 266 SG-DS-BLM 529 111 

Top Rear SG-DS-TRR SG-DS-TLR 

Bottom Rear SG-DS-BRR SG-DS-BLR 

Top Forward SG-CR-TRF SG-CR-TLF -636 -435 

Bottom Fwd. SG-CR-BRF SG-CR-BLF -840 -756 

Cant Rail 

(Longitudinal) 

Top Middle SG-CR-TRM SG-CR-TLM -507 -245 

Bottom Middle SG-CR-BRM SG-CR-BLM -444 -230 

Top Rear SG-CR-TRR SG-CR-TLR 

Bottom Rear SG-CR-BRR SG-CR-BLR 

79 
Table E-4. SOA Design: 100,000 lbf (30,500 N) Longitudinal Load on Corner Post, 

18 In. (460 mm) Above Floor 

Component Location 

Forward Surface Rear Surface 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Bottom Left SG-COR-BFL 2 765 SG-COR-BRL -698 -905 

Bottom Right SG-COR-BFR 484 729 SG-CORBRR -461 -645 

Corner Post 

(Vertical) 

Middle Left SG-COR-MFL -1124 -1224 SG-CORMRL 1135 1260 

Middle Right SG-CORMFR -1175 -1235 SG-CORMRR 1177 1091 

Top Left SG-COR-TFL 333 300 SG-COR-TRL -376 -343 

Top Right SG-COR-TFR 216 212 SG-CORTRR -376 -299 

Bottom Left SG-COL-BFL -192 -95 SG-COL-BRL 142 98 

Bottom Right SG-COL-BFR -275 -166 SG-COL-BRR 321 217 

Collision Post 

(Vertical) 

Middle Left SG-COL-MFL -317 -251 SG-COL-MRL 317 282 

Middle Right SG-COL-MFR -287 -266 SG-COLMRR 300 232 

Top Left SG-COL-TFL -23 -69 SG-COL-TRL 79 57 

Top Right SG-COL-TFR -173 -101 SG-COL-TRR 119 109 

Left Top SG-ATP-LFT -12 -107 SG-ATP-LRT 148 161 

Left Bottom SG-ATP-LFB -158 -157 SG-ATP-LRB 85 171 

AT Plate 

(Lateral) 

Middle Top SG-ATP-MFT -15 -86 SG-ATP-MRT 48 133 

Middle Bottom SG-ATP-MFB -40 -104 SG-ATP-MRB 34 122 

Right Top SG-ATP-RFT -27 -49 SG-ATP-RRT -57 100 

Right Bottom SG-ATP-RFB 82 -25 SG-ATP-RRB 21 64 

Left Top SG-LM-LFT 392 437 SG-LM-LRT -956 -982 

Lateral 

Member/Shelf 

(Lateral) 

Left Bottom SG-LM-LFB 356 400 SG-LM-LRB -1036 -1054 

Middle Top SG-LM-MFT 177 159 SG-LM-MRT -105 -124 

Middle Bottom SG-LM-MFB 152 148 SG-LM-MRB -101 -121 

Right Top SG-LM-RFT -95 -127 SG-LM-RRT 823 860 

Right Bottom SG-LM-RFB -206 -233 SG-LM-RRB 933 933 

Center Top SG-BB-CFT 155 113 SG-BB-CBT -120 -91 

End beam 

(Lateral) 

Center Bottom SG-BB-CFB 160 146 SG-BB-CBB -164 -129 

End Top SG-BB-EFT -15 -3 SG-BB-EBT 195 -442 

End Bottom SG-BB-EFB -10 5 SG-BB-EBB 25 12 

Outer Surface Inner Surface 

Component Location 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Top Forward SG-DS-TRF -98 223 SG-DS-TLF 117 373 

Bottom Fwd. SG-DS-BRF 292 228 SG-DS-BLF 238 211 

Draft Sill 

(Longitudinal) 

Top Middle SG-DS-TRM -46 150 SG-DS-TLM 81 142 

Bottom Middle SG-DS-BRM 290 272 SG-DS-BLM 292 129 

Top Rear SG-DS-TRR 58 SG-DS-TLR 40 

Bottom Rear SG-DS-BRR 102 SG-DS-BLR 92 

Top Forward SG-CR-TRF 85 SG-CR-TLF -79 -55 

Bottom Fwd. SG-CR-BRF 54 SG-CR-BLF -606 -562 

Cant Rail 

(Longitudinal) 

Top Middle SG-CR-TRM -10 SG-CR-TLM -234 

Bottom Middle SG-CR-BRM -37 SG-CR-BLM -260 

Top Rear SG-CR-TRR -148 SG-CR-TLR -110 

Bottom Rear SG-CR-BRR 10 SG-CR-BLR -27 

80 
Table E-5. SOA Design: 100,000 lbf (30,500 N) Lateral Load on Corner Post, 18 

In. (460 mm) Above Floor 

Component Location 

Forward Surface Aft Surface 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Bottom Left SG-COR-BFL 13 47 SG-COR-BRL -299 -297 

Bottom Right SG-COR-BFR -27 -65 SG-CORBRR 200 279 

Corner Post 

(Vertical) 

Middle Left SG-COR-MFL 131 201 SG-CORMRL 11 97 

Middle Right SG-CORMFR -238 -343 SG-CORMRR -118 -145 

Top Left SG-COR-TFL -160 -195 SG-COR-TRL -166 -273 

Top Right SG-COR-TFR 129 176 SG-CORTRR 139 131 

Bottom Left SG-COL-BFL 6 -2 SG-COL-BRL -90 -67 

Bottom Right SG-COL-BFR 137 90 SG-COL-BRR 88 49 

Collision Post 

(Vertical) 

Middle Left SG-COL-MFL 265 135 SG-COL-MRL 265 88 

Middle Right SG-COL-MFR -154 -60 SG-COLMRR -275 -120 

Top Left SG-COL-TFL -144 -57 SG-COL-TRL -135 -58 

Top Right SG-COL-TFR 167 84 SG-COL-TRR 158 89 

Left Top SG-ATP-LFT -307 -129 SG-ATP-LRT -409 -171 

Left Bottom SG-ATP-LFB 204 97 SG-ATP-LRB 226 102 

AT Plate 

(Lateral) 

Middle Top SG-ATP-MFT -40 -25 SG-ATP-MRT -55 -29 

Middle Bottom SG-ATP-MFB 13 -15 SG-ATP-MRB -10 -13 

Right Top SG-ATP-RFT 190 48 SG-ATP-RRT 349 148 

Right Bottom SG-ATP-RFB -164 -87 SG-ATP-RRB -349 -164 

Left Top SG-LM-LFT -322 -264 SG-LM-LRT -286 -345 

Lateral 

Member/Shelf 

(Lateral) 

Left Bottom SG-LM-LFB -299 -245 SG-LM-LRB -145 -211 

Middle Top SG-LM-MFT -190 -139 SG-LM-MRT -507 -484 

Middle Bottom SG-LM-MFB -175 -141 SG-LM-MRB -541 -515 

Right Top SG-LM-RFT -173 24 SG-LM-RRT -743 -701 

Right Bottom SG-LM-RFB -154 17 SG-LM-RRB -1147 -887 

Center Top SG-BB-CFT -205 -169 SG-BB-CBT -234 -167 

End beam 

(Lateral) 

Center Bottom SG-BB-CFB 56 17 SG-BB-CBB 6 -30 

End Top SG-BB-EFT -66 -6 SG-BB-EBT -73 60 

End Bottom SG-BB-EFB 54 6 SG-BB-EBB 48 -47 

Outer Surface Inner Surface 

Component Location 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Top Forward SG-DS-TRF -67 -19 SG-DS-TLF 37 -17 

Bottom Fwd. SG-DS-BRF 12 5 SG-DS-BLF 12 -5 

Draft Sill 

(Longitudinal) 

Top Middle SG-DS-TRM -13 -2 SG-DS-TLM 0 -9 

Bottom Middle SG-DS-BRM -23 -16 SG-DS-BLM 42 -15 

Top Rear SG-DS-TRR 33 SG-DS-TLR -21 

Bottom Rear SG-DS-BRR 17 SG-DS-BLR -31 

Top Forward SG-CR-TRF -12 SG-CR-TLF 46 38 

Bottom Fwd. SG-CR-BRF -19 SG-CR-BLF 42 -35 

Cant Rail 

(Longitudinal) 

Top Middle SG-CR-TRM -2 SG-CR-TLM 19 28 

Bottom Middle SG-CR-BRM -2 SG-CR-BLM 23 20 

Top Rear SG-CR-TRR 0 SG-CR-TLR 4 

Bottom Rear SG-CR-BRR 13 SG-CR-BLR 8 

81 
Table E-6. SOA Design: 100,000 lbf (30,500 N) Longitudinal Load on Collision Post, 

30 In. (760 mm) Above Floor 

Component Location 

Forward Surface Aft Surface 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Bottom Left SG-COR-BFL 0 -173 SG-COR-BRL 281 273 

Bottom Right SG-COR-BFR -197 -148 SG-CORBRR 173 88 

Corner Post 

(Vertical) 

Middle Left SG-COR-MFL -430 -396 SG-CORMRL 331 262 

Middle Right SG-CORMFR -326 -297 SG-CORMRR 410 379 

Top Left SG-COR-TFL -46 -55 SG-COR-TRL 35 102 

Top Right SG-COR-TFR -71 -89 SG-CORTRR -39 0 

Bottom Left SG-COL-BFL 812 856 SG-COL-BRL -806 -861 

Bottom Right SG-COL-BFR 769 877 SG-COL-BRR -817 -893 

Collision Post 

(Vertical) 

Middle Left SG-COL-MFL -1342 -1237 SG-COL-MRL 1510 1308 

Middle Right SG-COL-MFR -1350 -1285 SG-COLMRR 1521 1361 

Top Left SG-COL-TFL 88 21 SG-COL-TRL -46 -22 

Top Right SG-COL-TFR 6 15 SG-COL-TRR -54 -13 

Left Top SG-ATP-LFT -680 -687 SG-ATP-LRT 733 717 

Left Bottom SG-ATP-LFB -694 -675 SG-ATP-LRB 648 670 

AT Plate 

(Lateral) 

Middle Top SG-ATP-MFT -333 -370 SG-ATP-MRT 331 388 

Middle Bottom SG-ATP-MFB -326 -369 SG-ATP-MRB 331 388 

Right Top SG-ATP-RFT -31 -49 SG-ATP-RRT -60 55 

Right Bottom SG-ATP-RFB 36 -38 SG-ATP-RRB 40 81 

Left Top SG-LM-LFT -453 -247 SG-LM-LRT 949 826 

Lateral 

Member/Shelf 

(Lateral) 

Left Bottom SG-LM-LFB -396 -238 SG-LM-LRB 952 840 

Middle Top SG-LM-MFT -78 -24 SG-LM-MRT 211 82 

Middle Bottom SG-LM-MFB -72 -27 SG-LM-MRB 213 92 

Right Top SG-LM-RFT 223 163 SG-LM-RRT -541 -580 

Right Bottom SG-LM-RFB 196 162 SG-LM-RRB -670 -703 

Center Top SG-BB-CFT -162 -185 SG-BB-CBT 151 158 

End beam 

(Lateral) 

Center Bottom SG-BB-CFB -211 -182 SG-BB-CBB 243 264 

End Top SG-BB-EFT -37 -4 SG-BB-EBT 75 -182 

End Bottom SG-BB-EFB -35 -6 SG-BB-EBB 10 -32 

Outer Surface Inner Surface 

Component Location 

Gage 

Measured 

Strain (με) 

Model 

Strain (με) Gage 

Measured 

Strain (με) 

Model 

(Orientation) Strain (με)

Top Forward SG-DS-TRF -162 194 SG-DS-TLF 8 546 

Bottom Fwd. SG-DS-BRF 385 110 SG-DS-BLF 279 263 

Draft Sill 

(Longitudinal) 

Top Middle SG-DS-TRM -113 73 SG-DS-TLM -2 105 

Bottom Middle SG-DS-BRM 402 224 SG-DS-BLM 337 124 

Top Rear SG-DS-TRR -6 SG-DS-TLR -4 

Bottom Rear SG-DS-BRR 77 SG-DS-BLR 79 

Top Forward SG-CR-TRF 131 -318 SG-CR-TLF -494 -388 

Bottom Fwd. SG-CR-BRF 210 -552 SG-CR-BLF -831 -617 

Cant Rail 

(Longitudinal) 

Top Middle SG-CR-TRM 2 -219 SG-CR-TLM -421 -229 

Bottom Middle SG-CR-BRM 75 -214 SG-CR-BLM -404 -218 

Top Rear SG-CR-TRR -133 SG-CR-TLR -175 

Bottom Rear SG-CR-BRR 10 SG-CR-BLR -101 

82