U.S. Department

of Transportation Repair of Budd Pioneer Coach Car

Federal Railroad Crush Zones

Administration

Rail Passenger Equipment

Impact Tests

Office of Research

and Development

Washington, DC 20590

DOT/FRA/ORD 07/18 Final Report

May 2007

This document is available to the

public through the National Technical

Information Service, Springfield, VA 22161.

This document is also available on the FRA

Web site at www.fra.gov.
Notice 

This document is disseminated under the sponsorship 

of the Department of Transportation in the interest of 

information exchange. The United States Government 

assumes no liability for its contents or use thereof. 

Notice 

The United States Government does not endorse 

products or manufacturers. Trade or manufacturers’ 

names appear herein solely because they are 

considered essential to the objective of this report. 
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1. AGENCY USE ONLY (LEAVE BLANK) 2. REPORT DATE 

May 2007 

3. REPORT TYPE AND DATES COVERED 

Final Report 

May 2007 

4. TITLE AND SUBTITLE 

Repair of Budd Pioneer Coach Car Crush Zones 

5. FUNDING NUMBERS 

6. AUTHOR(S) RR28/DB035 

Ronald A. Mayville, Mayville and Associates; Robert J. Rancatore, TIAX LLC; Richard G. 

Stringfellow, TIAX LLC; Gabriel Amar, Taylor, Renault, Amar & Associates 

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

TIAX LLC* 

Acorn Park 

Cambridge, MA 02140-2390 

8. PERFORMING ORGANIZATION REPORT 

NUMBER 

DOT-VNTSC-FRA-07-02 

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-07/18 

11. SUPPLEMENTARY NOTES 

*Under Contract to: 

U.S. Department of Transportation 

Volpe National Transportation Systems Center 

55 Broadway 

Cambridge, MA 02142 

12A. DISTRIBUTION/AVAILABILITY STATEMENT 

This document is available to the 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. 

12B. DISTRIBUTION CODE 

13. ABSTRACT (MAXIMUM 200 WORDS) 

The research team conducted a project to repair cars for use in a full-scale train-to-train collision test with crash energy management 

systems. The two cars had been damaged in previous dynamic tests. Several components required replacement, and some required 

design modification. This report describes the damage to the cars from the tests, and the various actions needed to repair and modify 

the components. Some collision dynamics and finite element analyses were conducted in support of the modifications. The project 

included fabrication and assistance in implementing the repairs. 

14. SUBJECT TERMS 

Transportation, safety, crashworthiness, passenger rail vehicles, crash energy management 

(CEM) 

15. NUMBER OF PAGES 

52 

16. PRICE CODE 

17. SECURITY CLASSIFICATION 

OF REPORT 

 Unclassified 

18. SECURITY 

CLASSIFICATION

 OF THIS PAGE 

 Unclassified 

19. SECURITY 

CLASSIFICATION

 OF ABSTRACT 

 Unclassified 

20. LIMITATION OF ABSTRACT 
METRIC/ENGLISH CONVERSION FACTORS 

ENGLISH TO METRIC METRIC TO ENGLISH 

LENGTH (APPROXIMATE) 

1 inch (in) = 2.5 centimeters (cm) 

1 foot (ft) = 30 centimeters (cm) 

1 yard (yd) = 0.9 meter (m) 

1 mile (mi) = 1.6 kilometers (km) 

LENGTH (APPROXIMATE) 

1 millimeter (mm) = 0.04 inch (in) 

1 centimeter (cm) = 0.4 inch (in) 

1 meter (m) = 3.3 feet (ft) 

1 meter (m) = 1.1 yards (yd) 

1 kilometer (km) = 0.6 mile (mi) 

AREA (APPROXIMATE) 

1 square inch (sq in, in2

) = 6.5 square centimeters (cm2) 

1 square foot (sq ft, ft2

) = 0.09 square meter (m2) 

1 square yard (sq yd, yd2

) = 0.8 square meter (m2) 

1 square mile (sq mi, mi2

) = 2.6 square kilometers (km2) 

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

) 

AREA (APPROXIMATE) 

1 square centimeter (cm2

) = 0.16 square inch (sq in, in2) 

1 square meter (m2

) = 1.2 square yards (sq yd, yd2) 

1 square kilometer (km2

) = 0.4 square mile (sq mi, mi2) 

10,000 square meters (m2

) = 1 hectare (ha) = 2.5 acres 

MASS - WEIGHT (APPROXIMATE) 

1 ounce (oz) = 28 grams (gm) 

1 pound (lb) = 0.45 kilogram (kg) 

1 short ton = 2,000 pounds 

(lb) 

= 0.9 tonneP (t) 

MASS - WEIGHT (APPROXIMATE) 

1 gram (gm) = 0.036 ounce (oz) 

1 kilogram (kg) = 2.2 pounds (lb) 

1 tonne (t) = 

= 

1,000 kilograms (kg) 

1.1 short tons 

VOLUME (APPROXIMATE) 

1 teaspoon (tsp) = 5 milliliters (ml) 

1 tablespoon (tbsp) = 15 milliliters (ml) 

1 fluid ounce (fl oz) = 30 milliliters (ml) 

1 cup (c) = 0.24 liter (l) 

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, ft3

) = 0.03 cubic meter (m3) 

1 cubic yard (cu yd, yd3

) = 0.76 cubic meter (m3) 

VOLUME (APPROXIMATE) 

1 milliliter (ml) = 0.03 fluid ounce (fl oz) 

1 liter (l) = 2.1 pints (pt) 

1 liter (l) = 1.06 quarts (qt) 

1 liter (l) = 0.26 gallon (gal) 

1 cubic meter (m3

) = 36 cubic feet (cu ft, ft3) 

1 cubic meter (m3

) = 1.3 cubic yards (cu yd, yd3) 

TEMPERATURE (EXACT) 

[(x-32)(5/9)] °F = y °C 

TEMPERATURE (EXACT) 

[(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 6/17/9 

ii 
Preface 

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 (FRA). 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, FRA, for their 

support. The authors would also like to acknowledge the contributions of Eloy Martinez, Senior 

Engineer (now at FRA), and David Tyrell, Project Manager, both of the Volpe Center, for their 

guidance and insight; Patricia Llana, TIAX, which developed the finite element models; and 

Ebenezer Railcar Services, which fabricated the repair components. The authors would like to 

acknowledge Gunars Spons, of FRA, who coordinated efforts with the Transportation Technology 

Center, Inc. (TTCI). The authors would also like to acknowledge Tom Roderick, Joe Hanratty, 

and Bruce Perrin, Senior Technicians, TTCI. Without their input, the process would have taken 

longer. They were key to problem solving for some of the repairs. 

iii 

Table of Contents 

List of Figures................................................................................................................................... vi 

List of Tables .................................................................................................................................. viii 

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

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

2. Budd Pioneer Coach Car Crush Zone End Design ....................................................................... 5 

3. Condition of the Tested Crush Zones ........................................................................................... 7 

3.1 Coupler Hardware................................................................................................................. 10 

3.2 Buff Lug Hardware ............................................................................................................... 10 

3.3 Sliding Sill and Related Components ................................................................................... 11 

3.4 End Frame............................................................................................................................. 13 

3.5 Fixed Sill............................................................................................................................... 14 

3.6 Primary Energy Absorbers.................................................................................................... 15 

3.7 Sliding Sill/Fixed Sill Connection ........................................................................................ 16 

3.8 Roof Absorber Components ................................................................................................. 17 

4. Repair Descriptions..................................................................................................................... 19 

4.1 Preparation and Repair Sequence ......................................................................................... 19
 

4.2 Coupler Hardware................................................................................................................. 20 

4.3 Buff Lug Hardware............................................................................................................... 20 

4.4 Sliding Sill and Related Components—Retention Mechanism............................................ 20 

4.5 Anticlimber ........................................................................................................................... 21 

4.6 End Frame............................................................................................................................. 22 

4.7 Fixed Sill............................................................................................................................... 24 

4.8 Primary Energy Absorbers.................................................................................................... 24 

4.9 Sliding Sill/Fixed Sill Connection—Retention Mechanism................................................. 25 

4.10 Roof Absorber Components ............................................................................................... 30
 

5. Component Fabrication and Shipping ........................................................................................ 33 

6. Repair Examination .................................................................................................................... 35 

7. Summary and Conclusions ......................................................................................................... 37 

8. References................................................................................................................................... 39 

Acronyms and Abbreviations .......................................................................................................... 41 

v 
List of Figures 

Figure 1. Cab Car Crush in the Train-to-Train Test .......................................................................3 

Figure 2. Crush Zone End 244B Before Testing ............................................................................6 

Figure 3. Schematic of the Budd Pioneer Coach Car Crush Zone..................................................6 

Figure 4. Push-Back Coupler Honeycomb Absorber with Its Support Element After the 

Full-Scale Test...............................................................................................................10 

Figure 5. Bolt Hole in the Sliding Sill of One of the Crush Zones After the Test........................11 

Figure 6. Bell Mouth on End 248A After the One-Car CEM Test...............................................12 

Figure 7. Cover Plate on the Bottom of the Sliding Sill Immediately Below the Buff Lug.........12 

Figure 8. Back Surface of the End Beam After the CEM Test in the Area at Which the 

Primary Energy Absorber Contacts...............................................................................13 

Figure 9. Crack at the Connection Between the Sliding Roof Absorber Tube and the Back 

of the AT Beam for End 248A After the One-Car CEM Test ......................................14 

Figure 10. Fixed Sill for Car 248B Before Repair........................................................................15 

Figure 11. Condition of the Primary Energy Absorbers After the One-Car CEM Test; 

End 248A.....................................................................................................................16
 

Figure 12. Primary Energy Absorber from Car End 248B After the Two-Car Test ....................16 

Figure 13. Roof Absorber Elements from End 248A That Experienced Substantial Crush.........17 

Figure 14. Aluminum Honeycomb Roof Absorber Elements from End 244B After the 

Two-Car CEM Test .....................................................................................................18 

Figure 15. Access Hole Cut in the Floor Plate in the Vicinity of the Sliding Sill/Fixed Sill 

Connection...................................................................................................................19
 

Figure 16. Bell-Mouth Face Plate Repair .....................................................................................21
 

Figure 17. Anticlimber with Chamfered Edge Welded to the End Beam ....................................22 

Figure 18. Modified Inboard Surface of the End Beam in the Vicinity of the Primary Energy 

Absorbers and the New Retention Device...................................................................23 

Figure 19. Finite Element Results Comparing the Calculated Deformation of the End Beam
 

Due to the Loads from the Primary Energy Absorber During Crush (Cross Section 

Ahead of Primary Energy Absorbers): (a) Original Configuration and (b) Repaired 

Configuration...............................................................................................................23 

Figure 20. Newly Added Center Spacer on the AT Beam to Reduce Its Bowing When 

Coupled Ends Collide..................................................................................................24 

Figure 21. Plate Welded at the Inboard End of the Primary Energy Absorber to the Front 

Reaction Group............................................................................................................25 

Figure 22. Image of Part of the Sliding Sill Retention Device .....................................................26 

vi 
Figure 23. Results of Collision Dynamics Model for the Effect of Retention Device Stiffness 

on Calculated Maximum Load on the Device .............................................................27 

Figure 24. Calculated Load-Deformation Response for the Sliding Sill Retention Device .........28 

Figure 25. Calculated Deformation of the Retention Device: (a) Undeformed; (b) 0.6 in 

(15 mm); (c) 2.0 in (51 mm); (d) 3.3 in (84 mm) ........................................................29 

Figure 26. Inboard End of the Fixed Roof Absorber Tube After Removal of the End Plate to 

Extract Absorber Elements..........................................................................................30 

Figure 27. Rivet Pattern for the Repaired Roof Absorber Shear Joint (Top Surface)..................31 

Figure 28. Rivet Pattern for the Repaired Roof Absorber Shear Joint (Bottom Surface) ............31 

Figure 29. Repaired End of the Fixed Roof Absorber Tube and the Repaired Carline................32 

vii 
List of Tables 

Table 1. Test Positions of the Budd Pioneer Coach Car Crush Zones ...........................................7 

Table 2. Components Requiring Repair..........................................................................................8 

Table 3. Shear Bolt Test Results...................................................................................................34 

Table 4. Comparison of the Certification Tensile Properties of the A572-50 Used for the 

Primary Energy Absorbers..............................................................................................34 

viii 
Executive Summary 

The Volpe National Transportation Systems Center (Volpe Center) and the Federal Railroad 

Administration (FRA) conduct active research to improve rail vehicle crashworthiness. The 

Volpe Center and FRA conducted a baseline 30 mph (48 km/h) train-to-train crash test with 

conventional (strength-based) equipment in which the cab car was leading. The cab car 

experienced about 22 ft (6.7 m) of crush with substantial loss of occupied volume. Studies by 

the Volpe Center indicate that implementation of crash energy management (CEM) will greatly 

mitigate the amount of crush in such a collision, isolating deformation to unoccupied areas and 

preventing override and lateral buckling. The research team conducted one- and two-car tests on 

cars retrofitted with CEM crush zones on December 3, 2003, and February 26, 2004, 

respectively. 

The next phase of the program was to conduct a full-scale train-to-train test similar to the 

baseline test but with equipment in the moving train retrofitted with crush zones at each vehicle 

end (except for the locomotive). This program required a total of 10 crush zone ends: two cab 

car ends–one at the lead end of the moving train and one coupled to the trailing locomotive–and 

eight coach car ends. A separate program designed and built the two crush zone ends for the cab 

cars. Of the eight coach car crush zones, four were attached to Budd M1 cars, and the other four 

were repaired and modified versions of the crush zones tested in the one- and two-car CEM tests. 

A separate program adapted the existing coach car crush zone to the Budd M1 cars. The 

program described in this report focuses on the repair and modification of the tested Budd 

Pioneer crush zones that were used in the full-scale train-to-train test. The program includes 

examination and assessment of the condition of the tested cars, development of repairs and 

modifications to address some of the lessons learned in the previous tests, fabrication of 

components needed to achieve the repairs and modifications, and support in the actual repairs at 

the Transportation Technology Center (TTC). 

The crush zones performed as intended in the one- and two-car full-scale CEM crash tests. 

Damage was isolated to the components designed to be sacrificial and replaceable. The shear 

bolts of the push-back coupler fractured as intended, and the honeycomb absorber was crushed to 

the design value. (After the test, the buff lug had to be sacrificed in order to remove the 

honeycomb absorbers.) The bell-mouth plate and the coupler carrier were also damaged as the 

coupler pushed back, again as intended. An unexpected result was the deformation of the cover 

plate below the push-back coupler buff lug. The rear face of the end beam deformed in the area 

where the primary energy absorbers contacted it. In addition, the corner posts and the 

antitelescoping (AT) beam experienced a small amount of bowing due to impact between the top 

corner spacers and the impact wall. These modes of deformation required only minor repair. 

Both the sliding sill and the fixed sill shear bolt holes were slightly elongated; the hole 

elongation was more significant in the fixed sill. All sliding sill-to-fixed sill shear bolts fractured 

as intended during the trigger of the sliding sill. Each primary energy absorber was crushed to 

some extent so that none of them could be reused. The shear rivets of each roof absorber 

fractured, and some of the roof absorber cartridges crushed. Several uncrushed cartridges, 

however, could be reused. The two-car CEM test also revealed that the sliding components 

could be pulled out of the car as the cars rebounded from the impact. 

1
 
Many of the components required replacement using the original design and materials. These 

included the buff lug, the push-back coupler honeycomb absorber, the coupler carrier, the shear 

bolts and shear rivets, and the roof absorber cartridges. Some components required modification. 

The bell-mouth plate was restored to original condition by welding together pieces rather than 

using a single piece. A new, larger cover plate installed below the buff lug in the sliding sill 

prevented buff lug rotation during push back. Adding a plate to the back of the end beam 

reinforced the rear of the buffer beam. The AT beam and the corner posts were not straightened, 

but adjusting the spacers on the outboard surface of the AT beam compensated for the 

displacement associated with the slight bowing. A spacer was also added at the center of the AT 

beam to better distribute the impact load. The slightly elongated holes in the sliding and fixed 

sills were reused for the shear bolts. The primary energy absorbers had essentially the same 

design as before, but they were shortened by 1.5 in (38 mm) to account for the reinforcing plate 

on the back of the end beam and a plate at the inboard end of the absorber that was used to 

facilitate installation in the repaired cars. Modifications were made to the sliding tube of the roof 

absorber to prevent cracking at the welded connection to the AT beam. The shear rivet pattern 

was changed to permit access for the riveting tool now that the roof absorber system was 

assembled in the cars. A retention device was designed to prevent the sliding components from 

being pulled away from the car on rebound. This device attaches the ends of the primary energy 

absorbers to the end beam but transfers load only in draft. 

The program included the fabrication of the components needed for the repairs and assistance in 

carrying out the repairs at TTC. As part of the program, tests were conducted to determine the 

shear strength of the push-back coupler and sliding sill-to-fixed sill shear bolts. The research 

team conducted analysis on the design modifications made in the repair of the Budd Pioneer cars 

to verify that the crush zone would perform as intended. 

2
 
1. Introduction 

FRA and the Volpe Center are engaged in active research to improve rail vehicle 

crashworthiness. A key element of this program is the study of CEM, or crush zone, systems for 

passenger vehicles and the manner in which such technology provides practical benefit in 

American operations. The passenger rail equipment impact test program has completed fullscale tests on equipment designed to current, strength-based standards. These tests established a 

baseline against which improvements provided by CEM systems can be measured. 

The baseline train-to-train test consisted of a train moving at about 30 mph (48 km/h), with the 

cab car leading, colliding with a standing train in which the locomotive was the lead (impacted) 

vehicle. The cab car leading train included the cab car, followed by the equivalent of four coach 

cars and, at its aft end, a passenger locomotive. The cab car experienced about 22 ft (6.7 m) of 

crush in the test. Figure 1 shows the visible damage to the cab car after the test. Implementation 

of CEM will greatly mitigate the amount of crush in such a collision, isolating deformation to 

unoccupied areas and preventing override and lateral buckling. 

Figure 1. Cab Car Crush in the Train-to-Train Test 

The first part of the crush zone test program included design, fabrication, and testing of coach car 

crush zones for one- and two-car full-scale tests. These crush zones were designed for 

integration onto existing Budd Pioneer cars. The crush zones functioned as intended and 

experienced only minor damage. 

The next phase of the program, completed on March 23, 2006, was to conduct a full-scale trainto-train test essentially identical to the baseline test but with equipment in the moving train that 

has a crush zone at each vehicle end (except for the locomotive.). Thus, a total of 10 crush zone 

ends were needed: two cab car ends–one at the lead end of the moving train and one coupled to 

the trailing locomotive–and eight coach car ends. A subsequent program designed and built the 

two crush zone ends for the cab cars. Of the eight coach car crush zones, four were attached to 

Budd M1 cars, and the other four were repaired and modified versions of the crush zones tested 

3
 
in the one- and two-car CEM tests. A separate program adapted the existing coach car crush 

zone to the Budd M1 cars. 

The program described in this report focuses on the repair and modification of the tested Budd 

Pioneer crush zones so that they can be used in the next full-scale test. The program included 

examination and assessment of the condition of the tested cars, development of repairs and 

modifications to address some of the lessons learned in the test, fabrication of components 

needed to achieve the repairs and modifications, and support in the actual repairs at TTC. 

4
 
2. Budd Pioneer Coach Car Crush Zone End Design 

Figure 2 shows a photograph of one of the crush zone ends before testing. Separate documents 

[1-3] describe the design and fabrication of these crush zones. Figure 3 shows a model of a 

coach end structure with callouts to key components. The crush zones include the following key 

components (see also Figure 3): 

•	 A push-back coupler with energy absorber. The coupler is supported longitudinally by 

the yoke and draft gear elements, the latter of which are in turn supported by a buff lug. 

The buff lug is bolted to the sliding sill through eight shear bolts, four on each side. 

When the impact force on the coupler reaches a load of about 600,000 lbf (2,668 kN), the 

bolts shear and the buff lug moves back, crushing an aluminum honeycomb block. This 

block is in turn supported by a spacer bolted to the rear of the sliding sill. The push-back 

coupler absorbs approximately 330,000 ft-lb (0.45 MJ) of energy and has 0.67 ft 

(0.20 m) of stroke. 

•	 The sliding sill mechanism. The sliding sill provides a guide for the end crush of the car 

and a vertical and lateral load path for offset loads. It consists of a box beam sliding 

within guide channels. It is attached to the fixed sill through 12 shear bolts, six on each 

side. After the push-back coupler and its absorber are activated, the ends of coupled cars 

come into contact through the end beams (with ribbed anticlimbers), as well as spacer 

blocks on the AT plate. The load at the end frame rises, and the sliding sill shear bolts 

fracture when the impact load reaches a value of about 1,200,000 lbf (5,338 kN). 

•	 Primary energy absorbers. Two primary energy absorbers are on the car, one on each 

side of the centerline of the car. Each absorber consists of two crushable tubes that, at 

their inboard ends, are welded to and supported by car structure that is not intended to 

deform. The load on the outboard ends of the primary energy absorbers is applied by the 

back of the end beam. An initial gap exists between the outboard end of the absorber and 

the back of the end beam before activation of the crush zone (so that the absorbers do not 

carry operational loads). The energy absorbers absorb approximately 1,920,000 ft-lb 

(2.6 MJ) of energy and have 2 ft (0.6 m) of stroke. 

•	 Roof absorbers. Two roof absorber assemblies are on the car, one on each side. They 

consist of a plunger element attached to the back surface of the AT beam. This plunger is 

riveted to a tube of larger size that contains aluminum honeycomb cartridges. When the 

load at the roof absorber reaches a value of about 90,000 lbf (400 kN), the rivets shear 

and the plunger pushes back against the honeycomb pieces. The roof absorbers absorb 

approximately 220,000 ft-lb (0.3 MJ) of energy and have 2 ft (6 m) of stroke. 

•	 Integrated end frame. The integrated end frame is designed to remain sufficiently stiff in 

transmitting the impact load to the energy absorbers, ensuring the proper functioning of 

the crush zone elements. The integrated end frame can appropriately trigger and allow 

crushing of the energy absorbers when the couplers and the anticlimber share the impact 

load or when the lead path is only through the coupler or the anticlimber. 

5
 
Figure 2. Crush Zone End 244B Before Testing 

= 

= 

Sliding sill: 

Acts as a fuse and a 

guide; carries offset 

loads 

Push-Back Coupler Module 

Eabs = 0.4 MJ 

Primary Energy 

Absorber 

Eabs = 1.35 MJ (each) 

Roof Absorber 

Eabs = 0.15 MJ (each) 

Figure 3. Schematic of the Budd Pioneer Coach Car Crush Zone 

6
 
3. Condition of the Tested Crush Zones 

Table 1 lists the four crush zones that the researchers tested in the one- and two-car full-scale 

CEM tests. (See references 4 and 5 for more information on these tests.) The table includes the 

positions of each crush zone for these two tests. 

Table 1. Test Positions of the Budd Pioneer Coach Car Crush Zones 

Crush Zone End Test Position 

248A One-car Lead end 

248B Two-car Car 2, lead end 

244A Two-car Car 1, lead end 

244B Two-car Car 1, trailing end 

The research team used Car 248 for the one-car CEM test. The A-end impacted the rigid barrier 

at 34.1 mph (54.9 km/h). The crush zone was nearly exhausted with a total crush, not including 

coupler push back, of approximately 27 in (690 mm); the maximum possible crush of the crush 

zone is 30 in (760 mm). 

The crush zone was also exhausted for end 244A, which was at the impact interface in the twocar test. The other two ends, 248B and 244B, which were at the coupled interface of the two-car 

test, experienced a relatively small amount of crush. 

Table 2 lists the components that were damaged in the test and the required repair. The table 

discusses each component. 

7
 
Table 2. Components Requiring Repair

Subsystem Component Key Observations

Push-back 

coupler

Couplers

• The two couplers used on ends 244B and 248B were in good shape and could be r• The other two couplers used on ends 244A and 248A had part of the head cut off fo

could not be used for the next tests. 

Yokes and pins • The yokes used in the original crush zones were in good shape. 

Draft gear elements • The elements used in the original crush zones were in poor condition; all needed to 

Buff lug • The buff lugs on all four crush zones could not be reused. 

Buff lug shear bolts • All fractured. Push-back coupler,

honeycomb absorber

• The absorbers were crushed to some extent in all cases. For the B-ends, the abso

completely crushed; for the A-ends, the absorbers were crushed about 20 percent; replaced. 

Cover plate for the 

push-back coupler

• The cover plates were deformed; design needed to be changed. 

End beam

End beam rear surface

• The rear of the end beam on which the primary energy absorbers bear during crush 

the car end by about 0.25 in (6.4 mm) at its center. 

• The frames (intended to contain the absorbers laterally and vertically) had to be rem• The border around the dished area was relatively flat. 

Bell-mouth face plate

• The face plate was cut at the point at which it intersected with the angle side plates 

prepare for the repair. 

• The remnant was in good condition. 

Coupler carrier • The coupler carrier components were damaged beyond repair. 

Anticlimber

• The two anticlimbers were in good condition. • The plates were welded onto the end beam on two crush zone ends that required n

End frame AT beam

• The corner posts and the AT beam were bent back about 0.25 in (6.4 mm) on the c

impacted the crash barrier; spacer blocks had to be adjusted to account for the defo

Sliding

sill/fixed sill 

Holes in sliding sill for 

buff lug shear bolts

• The holes did not appear to be elongated in the longitudinal direction: the original (

was 0.813 in (20.7 mm); the measured dimension in the longitudinal direction did no0.815 in (20.7mm). 

Sliding sill-to-fixed sill

shear bolt holes

• The holes were elongated in the longitudinal direction: the original (nominal) diame

mm); the measured dimension in the longitudinal direction was as much as 1.10 in 

Fixed sill shear bolt 

holes 

• The sliding sill slid into the fixed sill with little resistance. • The holes were elongated in the longitudinal direction: the original (nominal) diame

mm); the measured dimension in the longitudinal direction was as much as 1.09 in 

• It did not appear to be possible to drill new holes without also removing the front rea

components welded to it; the drill was too large. 

• It was technically possible to enlarge the holes with a smaller tool, but it would have 

holes were left as is. 

8
 
Table 2. Components Requiring Repair (cont.)

Subsystem Component Key Observations

Primary

energy

absorbers

Primary energy 

absorbers

• The absorbers were crushed to some extent in all cases; for the B-ends, the absor

completely crushed; for the A-ends, the absorbers were crushed about 20 percent.

Front reaction group

• The surface of the center plate was in good condition after removal of the damaged 

absorbers. A i f h fl l b h l d id 

Roof absorber, sliding 

tube

• The sliding tubes were in very good condition. • The tubes slid easily into the fixed tubes. • The end that is against the AT beam needed modification because of cracks in the 

Roof

absorbers 

Roof absorber, fixed 

tube

• The end plate was removed to the absorber elements. • The fixed tubes were in very good condition. • A slight bulge was in one tube between intermittent welds where honeycomb mate• The existing rivet holes were only slightly elongated. • The area of shear rivet holes could not all be reached with the rivet tool.

Roof absorber, 

honeycomb elements

• Most of the honeycomb elements were crushed too much for reuse. • About 20 cartridges could be reused.

Roof absorber, adjacent 

carline 

• The carline immediately inboard of the inside end of the fixed tube required cutting 

honeycomb absorbers. 

9
 
3.1 Coupler Hardware 

The two couplers used on ends 244B and 248B experienced no damage and could be reused. 

The heads of the couplers on ends 244A and 248A had been cut off for the tests against the flat 

wall and therefore were not suitable for any of the ends in the CEM train-to-train test. The 

yokes, pins, and some of the draft gear pads also had no perceptible damage and could be reused. 

During the one-car test, the cover plates for the draft gear and push-back coupler components 

deformed. To avoid this deformation for the two-car test, an additional welded tie plate joined 

the buff lug cover plate and the lengthened draft gear cover plate. 

3.2 Buff Lug Hardware 

The buff lug hardware includes the buff lug, the shear bolts, the honeycomb absorber, and the 

honeycomb absorber support. The buff lug is a box structure that supports the draft gear before 

and after the push-back coupler is activated. The bolts that connect it to the sliding sill fractured 

(by shear), as intended, in all four car ends. The push-back coupler aluminum honeycomb 

absorber, which fits within the buff lug, crushed for each car end and could not be reused. In 

each case, the honeycomb jammed within the buff lug so that the lug had to be cut to remove the 

absorber for inspection. Therefore, all of the buff lugs also required replacement. The 

honeycomb absorber support was not damaged for any car end during the tests and could be 

reused. Figure 4 shows a photograph of one of the supports with the push-back coupler 

honeycomb absorber. 

Figure 4. Push-Back Coupler Honeycomb Absorber with Its Support Element After the 

Full-Scale Test 

10
 
3.3 Sliding Sill and Related Components 

Deformation of the sliding sill occurred only at the bolt holes that connect the sliding sill to the 

fixed sill; the holes for connecting the buff lug to the sliding sill were not perceptibly deformed. 

The holes that did deform were elongated in the longitudinal direction by less than 0.010 in (0.25 

mm) in every case. (The holes in the fixed sill showed greater deformation; see below.) Figure 

5 shows an example of the holes after the test. The sliding surface was generally in very good 

condition, but burrs were in proximity to the deformed holes, requiring limited grinding. 

The bell mouth on each crush zone was severely deformed, as intended. Figure 6 shows an 

example. The damaged components included the face plate and the coupler carrier hardware 

(two channels and three springs). The sides of the bell mouth experienced no significant 

damage. 

Figure 5. Bolt Hole in the Sliding Sill of One of the Crush Zones After the Test 

11
 
Figure 6. Bell Mouth on End 248A After the One-Car CEM Test 

The cover plate below the bottom buff lug and push-back coupler absorber deformed, as shown 

in Figure 7. A combination of load eccentricity on the buff lug from the draft gear and 

asymmetrical deformation of the honeycomb absorber led to large loads on this plate. To avoid 

this deformation, the cover plate required a modified design. 

Figure 7. Cover Plate on the Bottom of the Sliding Sill Immediately Below the Buff Lug 

12
 
3.4 End Frame 

The end frame includes the collision and corner posts, the end beam, the AT beam, and the shelf. 

Three areas experienced some damage as a result of the tests. 

The rear (inboard) face of the end beam deformed as a result of the high load from the primary 

energy absorbers. Figure 8 shows a photograph of this area for one of the cars. The deformation 

is not very clear from the photograph, but after the frame members were removed, use of a 

straight edge indicated that the face had deformed inward by approximately 0.125 in 

(3 mm) at its center. The inside of the end beam, which includes reinforcing gussets, was not 

opened for inspection. 

Figure 8. Back Surface of the End Beam After the CEM Test in the Area at Which the 

Primary Energy Absorber Contacts
 

The AT beam of ends 244A and 248A, which collided with the wall, experienced a perceptible 

bowing such that the center of the beam protruded outward further than the ends. The reason for 

this deformation is the loading on the AT beam spacers, positioned on the outboard surface 

adjacent to the corner posts, as they struck the test wall. The research team also observed a 

corresponding slight bowing in the corner posts. The magnitude of the AT beam bowing, as 

measured by the difference in longitudinal position between the center and either end, was 

approximately 0.25 in (6.4 mm). The researchers had to remove the AT beam spacers on ends 

244A and 248A because their dimensions are not appropriate for the case in which they are 

included at a coupled interface, as they will be in the CEM train-to-train test. 

Figure 9 shows evidence of cracking between the sliding tube of the roof absorber and the back 

of the AT beam for car end 248A. A fillet weld connects the sliding tube to the AT beam. 

13
 
Figure 9. Crack at the Connection Between the Sliding Roof Absorber Tube and the Back 

of the AT Beam for End 248A After the One-Car CEM Test 

The fixed tube of the roof absorber experienced no damage during the test with the exception of 

a slight bulge in a few locations. One or more of the honeycomb absorbers jammed within the 

tube, causing this bulge. The shear rivet holes were slightly elongated as a result of the shear 

load from the test. These holes, however, could not be reused because the riveting tool is too 

large to fit into the space adjacent to the holes. (The rivets were originally installed before the 

entire roof absorber was put into the car.) Finally, the end plate (on the inboard side of the fixed 

tube) was removed to permit extraction of the honeycomb elements. 

3.5 Fixed Sill 

As shown in Figure 10, the fixed sill was in good condition after the test. The points of largest 

deformation were the holes that contained the shear bolts for the connection to the sliding sill. 

These holes elongated in the longitudinal direction of the car by approximately 0.030 in (0.76 

mm), although variability occurred from hole to hole. As with the sliding sill, areas at the edges 

of the holes with burrs also required some grinding. After grinding, the sliding sill slid easily 

into the fixed sill for all four ends. 

14
 
Figure 10. Fixed Sill for Car 248B Before Repair 

3.6 Primary Energy Absorbers 

Figure 11 shows that the primary energy absorbers at the impacted end crush zones were almost 

completely crushed. The primary energy absorbers at the coupled ends of the two-car test also 

experienced permanent crush but of much lesser magnitude. Figure 12 shows the smallest 

amount of crush, which occurred in the absorbers on the trailing car at the coupled interface. 

Thus, all eight of the primary energy absorbers required replacement. The front reaction group, 

to which the inboard end of the primary energy absorber is welded, experienced no obvious 

damage for any end. 

15
 
Figure 11. Condition of the Primary Energy Absorbers After the One-Car CEM 

Test; End 248A 

Figure 12. Primary Energy Absorber from Car End 248B After the Two-Car Test 

3.7 Sliding Sill/Fixed Sill Connection 

A required modification found after the CEM tests was the connection between the sliding sill 

and the fixed sill. The research team observed that the sliding structure, which includes the 

16
 
sliding sill, the end frame, and the sliding roof absorber tubes, began to pull out of the car end as 

the cars rebounded from the wall in the two-car CEM test. No explicit mechanism in the test car 

crush zone ends prevented this tension load from developing after the sliding sill-to-fixed sill 

shear bolts are broken. In a car for actual service, the side and roof structure at the end would 

play this role. Thus, it was necessary in the repair of the cars to include some type of retention 

device. 

3.8 Roof Absorber Components 

The shear rivets of all roof absorbers sheared as a result of the test; depending on the location of 

the end, the aluminum honeycomb absorber cartridges substantially crushed. In addition, 

researchers observed cracking at the connection between the sliding roof absorber tube and the 

back of the AT beam (see Figure 9). 

Figures 13 and 14 show photographs of some honeycomb roof absorbers. The absorbers in 

Figure 13 are from end 248A. The absorbers in Figure 14 are from end 244B; a few of these 

experienced a minor amount of crush. The research team saved and reused approximately 20 

crush elements in the repair process. 

Figure 13. Roof Absorber Elements from End 248A That Experienced Substantial Crush 

17
 
Figure 14. Aluminum Honeycomb Roof Absorber Elements from End 244B After the 

Two-Car CEM Test 

18
 
4. Repair Descriptions 

This section describes the repairs and modifications made to the Budd Pioneer crush zones. The 

process for making these repairs and modifications included the development of initial concept 

layouts followed by discussions with the team, particularly the Volpe Center. The research team 

generated detailed drawings. In some cases, supporting finite element analyses were conducted. 

Researchers then used the drawings to procure repair components, and the components were 

shipped to TTC for implementation. 

4.1 Preparation and Repair Sequence 

The repair included preparation of the cars for new components and modifications. The sliding 

components were first removed from the car as a single unit and placed in a special location for 

examination and repair; Figure 6 shows one such end. Several components were then cut from 

the car, including the primary energy absorbers, the bell-mouth face plate, and the coupler 

carrier. The surfaces to which these components had been welded were then ground flat. Floor 

plate sections were cut for access in the vicinity of the inboard ends of the primary energy 

absorbers and in the area in which the sliding sill connects to the fixed sill. Figure 15 shows the 

access hole. 

Figure 15. Access Hole Cut in the Floor Plate in the Vicinity of the Sliding 

Sill/Fixed Sill Connection 

The general sequence of preparation and repair follows: 

1. Repair loose roof absorber sliding tube ends. 

2. Repair AT beam components and insert roof absorber sliding tubes into fixed tubes. 

19
 
3.	 Cut away floor and related components for primary energy absorber replacement. 

4.	 Partially insert sliding end (end frame/sliding sill) into fixed sill, and insert sliding sill 

inner components (push-back coupler components). 

5.	 Replace primary energy absorbers. 

6.	 Connect roof absorber tubes to end frame. 

7.	 Repair buffer beam back face. 

8. Complete installation of underframe components. 

9. Repair roof absorber fixed tube. 

10. Install AT beam spacers. 

4.2 Coupler Hardware 

As stated earlier, the team ordered two new couplers, identical to those used on ends 248B and 

244B, for installation on the A-ends. Some additional draft gear pads were also ordered. Some 

of these pads had a thickness that was too large and were consequently used inside the yoke (in 

draft). The pads that were formerly in the yoke were then used in buff (behind the yoke) after 

modification by adding welded steel bars to their bottom and sides for proper centering within 

the sliding sill pocket. 

4.3 Buff Lug Hardware 

Similarly, researchers ordered new aluminum honeycomb absorbers and new buff lugs, both with 

exactly the same design used for the original crush zones. The existing holes in the sliding sill 

served as the template for drilling the holes in the new buff lugs after they were positioned 

within the sliding sill. 

The team also ordered and installed a new carrier plate, covering the area from the back of the 

sliding sill to the edge of the yoke pin support plate. 

4.4 Sliding Sill and Related Components—Retention Mechanism 

The bell mouth represents the most substantial repair for this set of components. The damaged 

coupler carrier components and the bottom portion of the face plate were cut away, leaving two 

straight, vertical edges of the face plate. The replacement components for the coupler carrier had 

the same design as before, and the face plate was restored by welding two pieces onto the 

remaining portion using a single bevel groove weld. Figure 16 shows the repair. This provided 

a bell mouth with the same strength as for the original crush zone. 

The holes in the sliding sill did not need modification or repair except for some grinding and 

polishing to provide smooth sliding surfaces. 

20
 
Figure 16. Bell-Mouth Face Plate Repair 

4.5 Anticlimber 

Two of the ends, 248A and 244A, had flat plates in the place at which the ribbed anticlimber is 

normally situated. These flat plates were removed, and the remaining weld material was ground 

off of the end beam face. A slight depression (corresponding to the size of the original flat plate) 

remained in the end beam, and the edges of the new ribbed anticlimbers, which had the same 

geometry and material as used in the original 248B and 244B crush zones, were chamfered to 

ensure that good contact would occur between the rear of the anticlimber and the slightly 

depressed face of the end beam. Figure 17 shows the anticlimber welded in place. 

21
 
Figure 17. Anticlimber with Chamfered Edge Welded to the End Beam 

4.6 End Frame 

The primary repair on the end frame was the stiffening of the end beam’s rear face at the 

locations at which the primary energy absorbers contact. The collar on the back of the end beam 

into which the primary energy absorbers protrude was first removed on each side. The end beam 

surface was then built up with weld metal and ground as flat as possible. A 0.75 in (19 mm), 

A572-50 plate (or A36 in some cases), whose area was larger than the area originally bounded 

by the collar, was then welded onto the rear of the end beam; the rear thickness of the A710 

(minimum yield strength, 75 ksi [517 MPa]) end beam is 0.375 in (9.5 mm). The decreased 

length of the primary energy absorber accounted for this added plate (see below). Figure 18 

shows a photograph of this region, together with the new retention device and the primary energy 

absorber. 

22
 
Figure 18. Modified Inboard Surface of the End Beam in the Vicinity of the Primary 

Energy Absorbers and the New Retention Device 

Researchers conducted a finite element analysis to demonstrate the ability of this repair to 

prevent distortion of the end beam. Figure 19 shows images of the calculated deformation (in 

section) of the end beams for the original and repaired configurations. 

(a) (b) 

Figure 19. Finite Element Results Comparing the Calculated Deformation of the End 

Beam Due to the Loads from the Primary Energy Absorber During Crush (Cross 

Section Ahead of Primary Energy Absorbers): (a) Original Configuration and 

(b) Repaired Configuration 

23
 
The spacers on the outboard face of the AT beam were removed, and the AT beam face was 

ground smooth. New spacers were provided with a (vertical) height about 1 in greater than that 

of the original spacers. Researchers believed that this larger dimension would increase the 

certainty of car-to-car contact at the roof for the less controlled train-to-train test. An additional 

center spacer was also added to ensure that, on coupler push back, contact at the roof would 

occur in three locations instead of two, thus reducing the chances of bowing the AT beam and 

the corner and collision posts. Figure 20 shows a spacer welded to the AT beam. The spacers 

had a greater (longitudinal) length than in the original car 244 crush zones so that they could be 

machined during installation to ensure that proper contact would occur when the couplers push 

back. The final dimensions of the spacers also helped to compensate for the slight bowing of the 

corner posts and AT beam described earlier. 

Figure 20. Newly Added Center Spacer on the AT Beam to Reduce Its Bowing When 

Coupled Ends Collide 

The corner posts were adequately straight and did not require modifications or repairs. 

4.7 Fixed Sill 

Possible approaches to restore the shear bolt holes in the fixed sills to their original size included 

drilling holes in new locations or filling the previous holes with weld metal. None of these, 

however, could be carried out without substantial effort. In the end, the research team decided to 

leave the holes unmodified. The literature suggests that this will have little or no effect on the 

ultimate shear strength of the overall fixed sill-to-sliding sill joint (c.f. [6]). The sliding surfaces 

of the fixed sill were ground to provide a smooth surface. 

4.8 Primary Energy Absorbers 

The basic geometry–cross section, dividers, and trigger holes–and the type of material for the 

primary energy absorbers were the same as for the original crush zones. The decreased length of 

the absorbers accounted for the addition of the reinforcement on the end beam’s inboard face and 

24
 
for the addition of a plate at the absorber’s inboard end to facilitate reattachment to the absorber 

support structure. (Section 3.4 discusses the plate on the end beam.) A 0.75-in (19-mm) thick, 

A572-50 plate was also welded to the inboard end of the primary energy absorber (Figure 21). 

This plate was in turn welded to the face plate of the front reaction group. Researchers thought 

that this welding approach would provide a more feasible alternative than if the absorber tubes 

were welded directly to the front reaction group. In the original crush zones, that weld had been 

made in the shop before installation onto the car. Thus, the reduction in length of the crushable 

part of the primary energy absorber for the repaired cars was 1.5 in (38 mm). These repaired 

cars were near the end of the consist in the full-scale test, where the predicted crush was 

substantially less than 30 in (76 mm) of crush. 

Figure 21. Plate Welded at the Inboard End of the Primary Energy Absorber to the Front 

Reaction Group 

4.9 Sliding Sill/Fixed Sill Connection—Retention Mechanism 

Researchers designed a retention mechanism to ensure that the sliding components of the crush 

zone do not pull out if any of the cars rebound during the full-scale test. 

Figure 22 shows an image of the device’s part attached to the primary energy absorber. The 

device consists of a hook and slot. The hook is a bent part that is welded to the inside surfaces of 

the primary energy absorber and to two straps that are in turn welded to the top and bottom of the 

absorber. The slots are part of the new frame on the end beam’s rear surface that is used to 

restrict the primary energy absorber from lateral or vertical motion during crush. The top and 

bottom pieces of this frame each include a slot. 

25
 
Figure 22. Image of Part of the Sliding Sill Retention Device 

The dimensions of these new parts and their points of attachment were selected to ensure that no 

contact occurs between hook and slot during normal operation or during (inward) crush of the 

crush zone. The parts come into contact only if the end beam moves outward relative to the rest 

of the vehicle. 

Researchers conducted both collision dynamics and finite element analyses to select and 

demonstrate that the strength of the retention device is adequate. The collision dynamics model 

simulates the upcoming train-to-train test with CEM equipment. The model of each vehicle end 

with a crush zone was modified to allow the end of the car to slide outward. A spring element 

represented the retention device. (The original model includes coupler elastic response.) 

Calculations for a 30 mph (48 km/h) collision included different values of the retention spring 

stiffness. Figure 23 shows the calculated maximum force on the retention device as a function of 

device stiffness for the various coupled interfaces in the train. The force, and therefore the 

required strength, decrease as the stiffness decreases. This occurs because, with a lower 

stiffness, the retention force is applied over a longer time. Lower stiffness requires a greater 

device displacement. 

Figure 24 shows the calculated load-displacement response of the retention device that was 

installed on the cars, and Figure 25 shows the calculated deformation. These results are from a 

finite element analysis in which the back of the primary energy absorber was held and a rigid 

plate representing the end beam was displaced away from it at a speed of 30 mph (48 km/h). 

26
 
Sliding Sill Retention Force at Each Coupled End 

K=Retention Spring Stiffness 

Cab 

Car CC3 

CC2 

CC1 

CC0 

0 

20000 

40000 

60000 

80000 

100000 

Sill Retention Force (lbf) 

Crush Zone End 

K=1.2x10^6 lb/ft K=2.5x10^6 lb/ft 

Figure 23. Results of Collision Dynamics Model for the Effect of Retention Device 

Stiffness on Calculated Maximum Load on the Device 

27
 
Retainer Idealized Load-Crush Curve 

0 

25 

50 

75 

100 

125 

150 

175 

200 

0 1 2 3 4 5 6 

Displacement (inches) 

Load (1000 lbf) 

Figure 24. Calculated Load-Deformation Response for the Sliding Sill Retention Device 

28
 
(a) (b) 

(c) (d) 

Figure 25. Calculated Deformation of the Retention Device: (a) Undeformed; (b) 0.6 in 

(15 mm); (c) 2.0 in (51 mm); (d) 3.3 in (84 mm) 

29
 
4.10 Roof Absorber Components 

Each sliding roof absorber tube was removed from the AT beam and chamfered to accommodate 

a full penetration weld (in contrast to the fillet weld used previously). Researchers recognized 

that in some cases the bowing of the AT beam would result in a gap at some locations around the 

periphery of the sliding roof absorber tube end, but the welder would account for this gap. 

The rear plate of the roof absorber fixed tube required removal in order to extract the aluminum 

honeycomb cartridges. Figure 26 shows that the absorber tube deformed after the end plate was 

removed. In some instances, a section of the carline was also removed to allow extraction of the 

honeycomb cartridges. About one-half of the uncrushed honeycomb absorber cartridges were 

reused. The research team ordered the remaining required absorbers with the same specifications 

used for the original crush zone ends. Additional weld metal strengthened the regions at which a 

bulge had occurred in the fixed tube; the bulge remained untouched. 

Figure 26. Inboard End of the Fixed Roof Absorber Tube After Removal of the End Plate 

to Extract Absorber Elements 

Figures 27 and 28 show the locations of the new rivet holes for the connection between the fixed 

and sliding roof absorber tubes. The pattern is not as symmetrical as it is for the original 

configuration, but the rivet-to-rivet spacing is essentially unchanged, and the expectation is that 

the total shear strength of the joint will be close to that of the original. Researchers used the 

same type of rivets as for the original fabrication. 

30
 
Figure 27. Rivet Pattern for the Repaired Roof Absorber Shear Joint (Top Surface) 

Figure 28. Rivet Pattern for the Repaired Roof Absorber Shear Joint (Bottom Surface) 

The inboard end plate on the fixed tube was cut and welded within the end of the tube, about 

0.75 in (19 mm) from the end. This ensured that a good weld could be made around the entire 

perimeter of the end plate since part of the outside of the tube was not accessible in the installed 

position. (Recall that the absorber had originally been fabricated, with its end plate, before 

31
 
installation into the original crush zone.) Where removed, the carline section was Huck-bolted to 

the existing carline. Figure 29 shows the repaired roof absorber end and carline. 

Figure 29. Repaired End of the Fixed Roof Absorber Tube and the Repaired Carline 

32
 
5. Component Fabrication and Shipping 

Ebenezer Railcar Service, West Seneca, NY, fabricated most of the components that were 

needed to conduct the Budd Pioneer crush zone repairs. Ebenezer fabricated the original crush 

zone components. Ebenezer used a quality control document specific to the components for 

these repairs and followed Association of American Railroads M-1003 [7] quality control 

requirements. All welding was conducted according to American Welding Society D15.1 

criteria [8]. The quality control ream collected or checked the following information: 

•	 Material certifications, particularly the shear bolts and the material for the primary energy 

absorbers as described below 

•	 Dimensions of the incoming materials; most of the components were cut to shape before 

delivery to Ebenezer 

•	 Dimensions of bent components 

•	 Dimensions of finished assemblies 

•	 Photographs of assemblies during and after fabrication 

The certificates for the shear bolts ensured that they satisfied the requirements for A490 bolts 

and had measured properties similar to what had been used before. Some shear strength tests 

conducted on the bolts show their material properties. In particular, two tests, conducted 

according to American Society for Testing and Materials F606-D2 for the 0.75-in (19-mm) 

diameter (push-back coupler buff lug) bolts and the 1.0-in (25.4-mm) diameter (sliding sill-tofixed sill) bolts, showed that the average shear strengths were 51,200 lbf (229 kN) and 78,300 lbf 

(350 kN), respectively. These values are within the range assumed in design. Table 3 gives the 

individual test results for these bolts, as well as the test results from the original crush zone 

program. 

33
 
Table 3. Shear Bolt Test Results 

Bolt Diameter 

(in)/(mm) 

Bolt 

Grade 

Shear 

Strength 

(lbf)/(kN) 

Shear Strength 

(lbf/in2

)/(MPa) 

From current program 

0.75 / 19 A490 44,200 / 197 100,000 / 690 

0.75 / 19 A490 58,300 / 260 132,000 / 910 

1.00 / 25.4 A490 79,100 / 353 101,000 / 696 

1.00 / 25.4 A490 77,500 / 350 98,700 / 680 

From previous program 

0.875 / 22 A490 62,400 / 279 104,000 / 717 

0.875 / 22 A490 64,400 / 288 107,000 / 738 

0.875 / 22 A490 64,700 / 289 108,000 / 745 

1.00 / 25.4 Gr.8 87,200 / 389 111,000 / 765 

1.00 / 25.4 Gr.8 89,200 / 398 114,000 / 786 

1.00 / 25.4 Gr.8 89,100 / 398 113,000 / 779 

Table 4 shows the comparison of the certified mechanical properties for the A572-50 steel used 

for the replacement primary energy absorbers with the certified properties of the original 

absorbers. The differences are less than 10 percent and acceptable. 

Table 4. Comparison of the Certification Tensile Properties of the A572-50 Used for the 

Primary Energy Absorbers 

Property Original Material (1) Repair Material (2) 

Yield strength (ksi)/(MPa) 63 / 434 60 / 414 

Tensile strength (ksi)/(MPa) 77 / 531 84 / 579 

Elongation in 2 in (percent) 34 28 

The fabricated components and piece parts needed for the repair arrived by flatbed truck to TTC, 

where the repairs were made. 

34
 
6. Repair Examination 

Participation in the repair procedure included discussions, primarily by telephone, to 

troubleshoot problem areas and visits to TTC to examine the cars during and after repair. This 

section provides some notes on areas that required modification or whose characterization it was 

thought could be useful in the eventual interpretation of the full-scale tests. In general, the repair 

procedure went smoothly, and few deviations from the original repair design were made. 

Key items include: 

1.	 Researchers put the honeycomb blocks for the push-back coupler together from leftover 

6,500 psi (44.8 MPa) material from the previous crush zone project. This helped to 

overcome a delay caused by late delivery of new honeycomb blocks. 

2.	 The new buff lugs did not fit into the sliding sill without interference, particularly with 

the cover plate, and needed to be ground to ensure that proper sliding would occur. 

3.	 Distortion in the cars and slight imperfections in the fabrication of the primary energy 

absorbers sometimes caused the outboard (impacted) end of the absorber to be out of 

position. Various modifications were made depending on the car end and side. These 

included slight machining of the end of the absorber and machining of the plates of each 

end to which the absorber either attaches or impacts. 

35
 

7. Summary and Conclusions 

This report describes the process followed to repair four Budd Pioneer crush zones. These two 

cars had been used in previous crash tests, and a need existed to repair them for use in an 

upcoming CEM train-to-train test. 

The crush zones performed as intended in the one- and two-car full-scale CEM crash tests. 

Damage was almost entirely isolated to the components designed to be sacrificial and 

replaceable. The shear bolts of the push-back coupler fractured as intended, and the honeycomb 

absorber crushed to the design value. The buff lug had to be sacrificed in order to remove the 

honeycomb absorbers. The bell-mouth plate and the coupler carrier were also damaged as the 

coupler pushed back, again as intended. An unexpected result was the deformation of the cover 

plate below the push-back coupler buff lug. The rear face of the end beam deformed in the area 

at which the primary energy absorbers contact. In addition, the corner posts and the AT beam 

experienced a small amount of bowing due to impact between the top corner spacers and the 

impact wall. These unanticipated modes of deformation required only minor repair. The only 

deformation to the sliding sill was at the shear bolt holes, which were slightly elongated; the hole 

elongation was more significant in the fixed sill. All sliding sill-to-fixed sill shear bolts fractured 

as intended. Each primary energy absorber crushed to some extent so that none of them could be 

reused. The shear rivets of each roof absorber fractured; depending on the location of the car end 

in the full-scale test, the roof absorber cartridges crushed. Several of the cartridges, however, 

could be reused. The two-car CEM test also revealed that the sliding components could be 

pulled out of the car as the cars rebound from the impact. 

Many of the components required replacement using the original design and materials. These 

included the buff lug, the push-back coupler honeycomb absorber, the coupler carrier, the shear 

bolts and shear rivets, and the roof absorber cartridges. Some components required modification. 

The bell-mouth plate was restored to original condition by welding together pieces rather than 

from a single piece. A new, larger cover plate was installed below the buff lug in the sliding sill 

to prevent buff lug rotation during push back. The rear of the buffer beam was reinforced by 

adding a plate to the back of the end beam. The AT beam and the corner posts were not 

straightened, but the displacement associated with the slight bowing was compensated for by 

adjusting the spacers on the outboard surface of the AT beam. A spacer was also added at the 

center of the AT beam to better distribute the impact load. The slightly elongated holes in the 

sliding and fixed sills were reused for the shear bolts because evidence in the literature indicates 

that little change would occur in the overall joint strength. The primary energy absorbers had 

essentially the same design as before, but they were shortened by 1.5 in (38 mm) to account for 

the reinforcing plate on the back of the end beam and a plate at the absorber’s inboard end that 

was used to facilitate installation in the repaired cars. Modifications were made to the sliding 

tube of the roof absorber to prevent cracking at the welded connection to the AT beam. The 

shear rivet pattern was changed to permit access for the riveting tool now that the absorber 

assemblies are in the cars. A retention device was designed to prevent the sliding components 

from being pulled away from the car on rebound. This device attaches the ends of the primary 

energy absorbers to the end beam but transfers load only in draft. 

37
 
The project included fabrication of the components needed for the repairs and assistance in 

carrying out the repairs at TTC. As part of the project, component tests helped determine the 

shear strength of the push-back coupler and the sliding sill/fixed sill shear bolts. 

38
 
8. References 

1.	 Mayville, R.A., Stringfellow, R.G., Rancatore, R., and Johnson, K., “Development of a 

Passenger Rail Vehicle Crush Zone.” Proceedings of the 1999 IEEE/ASME Joint Railroad 

Conference, April 13-15, 1999, Dallas, TX. 

2.	 Mayville, R., Johnson, K.N., Stringfellow, R.G., and Tyrell, D.C., “The Development of a 

Rail Passenger Coach Car Crush Zone.” Proceedings of 2003 ASME/RTD and IEEE Joint 

Rail Conference, April 22-24, 2003, Chicago, IL; Paper JRC2003-1653. 

3.	 Martinez, E., Tyrell, D., and Perlman, A.B., “Development of Crash Energy Management 

Design for Existing Passenger Rail Vehicles.” 2004 ASME International Mechanical 

Engineering Congress and Research and Development RD&D Expo, Anaheim, CA, 

November 15-19, 2004; Paper IMECE2004-61601. 

4.	 Tyrell, D., “Passenger Rail Train-to-Train Impact Test Volume I: Overview and Selected 

Results.” U.S. Department of Transportation, DOT/FRA/ORD-03/17.I, July 2003. 

5.	 Jacobsen, K., Tyrell, D., and Perlman, A.B., “Impact Tests of Crash Energy Management 

Passenger Rail Cars: Analysis and Structural Measurements.” 2004 ASME International 

Mechanical Engineering Congress and Research and Development RD&D Expo, Anaheim, 

CA, November 15-19, 2004; Paper IMECE2004-61252. 

6.	 Allan, R.N., and Fisher, J.W., “Bolted Joints with Oversize and Slotted Holes.” Journal of 

the Structural Division, ASCE, Vol. 94, ST9 (September 1968). 

7.	 Association of American Railroads. Manual of Standards and Recommended Practices, 

Section J, Specification for Quality Assurance. M-1003 (August 2000). 

8.	 American Welding Society. Railroad Welding Specification–Cars and Locomotives. Miami, 

FL, AWS D15.1 (2000). 

9.	 ASTM F606, Standard Test Methods for Determining the Mechanical Properties of 

Externally and Internally Threaded Fasteners, Washers, and Rivets. ASTM International, 

West Conshohocken, PA. 

39
 

Acronyms and Abbreviations 

AT antitelescoping 

CEM crash energy management 

FRA Federal Railroad Administration 

ksi kips per square inch 

TTC Transportation Technology Center 

Volpe Center Volpe National Transportation Systems Center 

41