Development of a Retrofit End Enclosure for Enhanced Light-Rail-Vehicle Collision Safety with Automobiles

A prototype end enclosure, or bumper, was designed to retrofit the Siemens SD660 LRV (light-rail vehicle). The objective of the design was to reduce potential for injury to automobile occupants and damage to the LRV car body, and to lower costs to operators from crashes. The bumper was designed using nonlinear dynamic finite-element analysis. Side and oblique impact simulations were performed against a small car (2010 Toyota Yaris) and an SUV (2003 Ford Explorer). Injuries caused by collision were evaluated using a model of the ES-2re Side Impact Dummy (SID). Injuries were calculated for the head, chest, abdominal area, and neck using the abbreviated injury scale (AIS). Simulations were performed for LRV impact speeds of 20 mph against the automobiles. For this speed, the bumper is designed to remain usable in service. Adding the bumper to the collision interface significantly reduced the potential for serious injuries in all the collision scenarios evaluated. For the 2003 Explorer, injuries were reduced from an AIS3+ (serious) chest injury probability of 48.5% without bumper to 21.8% with the bumper when considering normal (90°) side impact. For the 2010 Yaris, injuries were reduced from 100% AIS6+ (fatal) injury probability, resulting from head impact against the LRV anticlimber, to 12.4%. The bumper was also designed to be functional and remain in service for LRV-to-LRV crash speeds of 5 mph. To protect against LRV collisions at higher speeds, the bumper side panels break away at 11 mph, and the existing LRV crash-energy-management performance is unaffected.