Structural Crashworthiness of Railway Vehicles

As a form of transport, rail has always maintained lower accident levels than its counterparts, the car and the airplane. The railway industry, however strives for still better safety measures to be implemented – a fact which intensifies with each accident that occurs. In the last years the continuous developments in technology, computer modeling capabilities and know-how have opened up various research activities in the passive safety area, also known as crashworthiness. Whereas the objective of active safety systems (such as signalling and automatic train protection systems) is to avoid accidents, passive safety only comes into effect in the event of collision and its objective is to significantly reduce the severity of accidents. Rail vehicles can be designed to behave in ways that minimize the injuries of passengers and crew during collisions. Crashworthy vehicles contain in-built design features, which are not relevant in normal train operations, but protect the train occupants should an accident occur. A methodology has been developed within the projects TRAINCOL, SAFETRAIN and SAFETRAM for improved passive safety in railway transportation. This methodology includes: i) A review of past accidents, identification of reference collision scenarios and evaluation of their consequences. Risk assessment for improved passive safety was also considered; ii) The establishment of a set of reference collision scenarios for main line train and city tram operations. Together with statistical and risk analysis, design feasibility studies played a major role in the definition of the reference scenarios; iii) The development of a general framework for structural crashworthiness design train and in city and periurban tram vehicles and iv) Guidelines for design validation procedures through modeling, component and real size dynamic testing. Improved passenger and crew safety issues have been systematically addressed. Passenger and crew accommodations on a number of railways within Europe have been reviewed from the standpoint of interior safety. Conclusions about typical acceleration pulses and appropriate values of injury criteria for the railway industry have also been established. One of the most important achievements of these projects was then to demonstrate the feasibility of optimized carbody structures to present an improved safety level to occupants, within acceptable cost and masses for the defined construction solutions. A European Standard is now being completed providing the framework for determining the crash conditions that railway vehicle bodies should be designed to sustain based on the most common accidents and associated risks. It also defines suitable passive safety features to meet the requirements.