Preliminary Finite Element Analysis of Locomotive Crashworthy Components

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. In recognition of the importance of override prevention in train-totrain collisions in which one of the vehicles is a locomotive, and in light of the success of crash energy management technologies in cab car-led passenger trains, the Volpe Center seeks to evaluate the effectiveness of components that could be integrated into the end structure of a locomotive that are specifically designed to mitigate the effects of a collision and, in particular, to prevent override of one of the lead vehicles onto the other. A research program is being conducted that aims to develop, fabricate and test two crashworthy components for the forward end of a locomotive: (1) a deformable anti-climber, and (2) a push-back coupler. Preliminary designs for these components have been developed. This paper provides details on the finite element models of the crashworthy components and how the component designs behave in the finite element analyses. The component designs will be evaluated to determine if the requirements have been met, such as the energy absorption capability, deformation modes, and force/crush characteristics. INTRODUCTION In the event of a collision between two trains, a considerable amount of energy must be dissipated. One of the potential consequences of such a collision is override of one of the vehicles onto the other. Locomotives, because of their great longitudinal strength and stiffness, are particularly susceptible to override when they collide with another vehicle, and the consequences can be catastrophic. Research has shown that conventional anti-climbing structures can deform on impact and form a ramp, increasing the likelihood of override [1 Figure 1 ]. As they crush longitudinally, conventional anti-climbers lose their vertical load carrying capacity due to the substantial fracture that occurs as the anti-climber crushes. The longitudinal crush of the anti-climber causes fracture in the webs behind the face of the anti-climber. These fractured webs can still resist a longitudinal compression load, but can no longer transmit a vertical shear load. This loss of vertical load-carrying capacity in conventional anti-climbers often leads to ramp formation, which promotes override. Such behavior was exhibited in a head-on collision that occurred in West Eola, Illinois on January 20, 1993. As seen in , the accident resulted in one locomotive (right side of photo) overriding the other locomotive, crushing the operator’s cab. The photograph shows the overriding locomotive lifted off of its lead truck. In order to be effective, an anti-climber must engage the end structures of opposing equipment and provide sufficient vertical load capacity to prevent such override. Figure 1. West Eola, Illinois Head-On Collision, January 20, 1993 [1].