Development of Crash Energy Management for Light Rail Vehicles

Rail vehicle safety standards for the United States have historically placed emphasis on static structural strength requirements to ensure safety. The primary requirements to ensure crash safety of light rail vehicles were static load cases including car body buff loads, collision post loads, corner post loads, etc. More recent developments for light rail vehicles in the United States have included crash energy management design methodologies. This is consistent with the trend in other modes of transportation applying modern crashworthiness engineering. The challenges of incorporating crash energy management into light rail vehicles are the lack of crashworthiness standards for the light rail industry, the introduction of new design methodologies, and the concerns of compatibility of new and older equipment. This issue of compatibility in vehicle designs would often inhibit introduction of innovations and potential safety improvements within an existing light rail transit system. However, there are ongoing efforts to address each of these challenges. The American Society of Mechanical Engineers has a committee working on the development of a new safety standard for light rail vehicles. Light rail vehicle manufacturers are increasingly using modern crashworthiness design principles. In addition, modern crash analysis methodologies allow for the assessment of vehicle incompatibilities in the design process. In this paper, the developments of crash energy management strategies in the light rail industry are discussed. These include the ongoing standards development efforts and the application of crash energy management principles in recent light rail vehicle design efforts. Examples will be provided for the use of crash analyses in a vehicle design. The interaction of the crash and static analyses will be discussed and examples of both compatible and incompatible collision scenarios will be presented.