In train collisions, multi-level rail passenger vehicles can deform in modes that are different from the behavior of single level cars. The deformation in single level cars usually occurs at the front end during a collision. In one particular incident, a cab car buckled laterally near the back end of the car. The buckling of the car caused both lateral and vertical accelerations, which led to unanticipated injuries to the occupants. A three-dimensional collision dynamics model of a multi-level passenger train has been developed to study the influence of multi-level design parameters and possible train configuration variations on the reactions of a multi-level car in a collision. This model can run multiple scenarios of a train collision. This paper investigates two hypotheses that could account for the unexpected mode of deformation. The first hypothesis emphasizes the non-symmetric resistance of a multi-level car to longitudinal loads. The structure is irregular since the stairwells, supports for tanks, and draglinks vary from side to side and end to end. Since one side is less strong, that side can crush more during a collision. The second hypothesis uses characteristics that are nearly symmetric on each side. Initial imperfections in train geometry induce eccentric loads on the vehicles. For both hypotheses, the deformation modes depend on the closing speed of the collision. When the characteristics are non-symmetric, and the load is applied in-line, two modes of deformation are seen. At low speeds, the couplers crush, and the cars saw-tooth buckle. At high speeds, the front end of the cab car crushes, and the cars remain in-line. If an offset load is applied, the back stairwell of the first coach car crushes unevenly, and the cars saw-tooth buckle. For the second hypothesis, the characteristics are symmetric. At low speeds, the couplers crush, and the cars remain in-line. At higher speeds, the front end crushes, and the cars remain in-line. If an offset load is applied to a car with symmetric characteristics, the cars will saw-tooth buckle.

Priante, M., “A Collision Dynamics Model of a Bi-Level Car,” Tufts University Master’s Thesis, May 2006.
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.
Parent, D., Tyrell, D., Perlman, A.B., “Crashworthiness Analysis of the Placentia, CA Rail Collision,” Proceedings of ICrash 2004, International Crashworthiness Conference, San Francisco, California, July 14–16, 2004.
National Transportation Safety Board. 2003. Collision of Burlington Northern Santa Fe Freight Train with Metrolink Passenger Train Placentia, California, April 23, 2002. Railroad Accident Report NTSB/RAR-03/04, Washington, DC.
Tyrell, D.C., Perlman, A.B., “Evaluation of Rail Passenger Equipment Crashworthiness Strategies,” Transportation Research Record No. 1825, pp. 8–14, National Academy Press, 2003.
Tong, P., “Mechanics of Train Collision,” 1976, Final Report FRA-OR&D-76–246, Cambridge, Massachusetts.
Severson, K., “Development of Collision Dynamics Models to Estimate the Results of Full-Scale Rail Vehicle Impact Tests,” Tufts University Master’s Thesis, November 2000.
Jacobsen, K., Tyrell, D., Perlman, A.B., “Impact Tests of Crash Energy Management Passenger Rail Cars: Analysis and Structural Measurements,” American Society of Mechanical Engineers, Paper No. IMECE2004-61252, November 2004.
Martinez, E., Zolock, J., Tyrell, D., “Crush Analyses of Multi-Level Equipment,” American Society of Mechanical Engineers, Paper No. IMECE2006-13214, November 2006.
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