Crashworthiness of High-Speed Trains

The U.S. Federal Railroad Administration (FRA), through its Office of Safety, is engaged in a program to assess overall collision safety for new major high-speed passenger rail corridors. This assessment covered both collision avoidance and collision survivability for one existing and proposed major US high-speed passenger rail corridor. In this research study, the focus was to determine, for a wide range of collision scenarios, the crashworthiness and occupant survivability of the two rail systems.

Our basic approach for crashworthiness assessment had three steps. The first was to characterize the crash response of individual rail cars. For the North American train systems, we developed a detailed finite element model of a passenger car based on simplified assembly drawings. We characterized the crushing response of the car by simulating 30 and 60 mph collisions of the car with a 50 ton rigid, but moveable, mass. An example of the detailed model for a 60 mph collision is shown in Figure 1. The response of the train car and the internal structural frame for the 60 mph collision are shown in Movie 1 and Movie 2, respectively. From these calculations, we determined the collision response mechanisms for the train car and developed force-crush and force-energy curves. A corresponding simulation of an alternative train car design impacting a catenary pole is shown in Movie 3.

A more recent study involved a full scale test where a passenger rail car was crashed into a rigid wall at 35 mph. We were involved in documenting the crash behavior, analyzing the recorded crash data, and using that information to construct a detailed FEA model of the test. This program is described in the link: Single Car Crash Test.

The second step was to characterize train collision dynamics. We developed simpler finite element models of train cars that had crush characteristics similar to those calculated with the detailed model. We then calculated a range of train collision scenarios and determined the loss of occupied volume in crush zones and the acceleration histories in each of the train cars. These calculated acceleration histories for the train cars define the interior crash environments experienced by the passengers. An example of a very simple collision dynamics simulation for a three car consist impacting a 50 ton mass at 60 mph is shown in Movie 4. A similar simulation of the lateral buckling response for the derailment of freight train is shown in Movie 5.

The third step was to calculate the occupant response. We developed a finite element model of the occupants based on the structures and technology developed for anthropomorphic crash dummies used in automotive crash safety assessment. An interior model for the train car was developed from seat assembly drawings and force deflection measurements on the seat back. Occupant survivability was then assessed for secondary impacts resulting from the crash acceleration histories obtained from the collision dynamics calculations. A simulation of a 15 mph occupant secondary impact response is shown in Figure 2. An animation of the occupant secondary impact response is shown in Movie 6.

References:

S.W. Kirkpatrick, M. Schroeder, and J.W. Simons, "Evaluation of Passenger Rail Vehicle Crashworthiness," International Journal of Crashworthiness, IJCrash Vol. 6 No. 1 pp. 95-106, 2001.
Abstract

Kirkpatrick, S.W. and MacNeill, R.A., "Development of a Computer Model for Prediction of Collision Response of a Railroad Passenger Car," Proc. JRC2002, The 2002 ASME/IEEE Joint Rail Conference, Washington D.C., Apr. 23-25, 2002.
Abstract
J.W. Simons and S.W. Kirkpatrick, "High-Speed Passenger Train Crashworthiness and Occupant Survivability," International Journal of Crashworthiness, IJCrash Vol. 4, No. 2, pp. 121-132, 1999.
Abstract

For inquiries or comments, please contact:
Dr. Steven Kirkpatrick
Principal Engineer
e-mail: skirkpatrick@ara.com
Dr. Robert T. Bocchieri
Principal Engineer
e-mail: rbocchieri@ara.com