Safety Verification for Train Traffic Control Communications

Railway interlocking systems are the technical equipment of the operative train traffic control, regulating the routes and the speed of train units. Their basic task is to ensure the safety of the train traffic and shuntings, and to avoid dangerous situations. The safety provided by the interlocking system at normal operation and at breakdowns, namely the safety against dangers, must be proved by a so-called safety verification. This verification must prove that the failures which are considered possible do not cause fail/dangerous/system outputs. To verify the safety there are several procedures known, for example: simulation methods, various theoretical ways, practical tests, and their combinations. The simulation-based testing system RWS-3/Railway Simulator/has been developed by the Department of Transport Automation at the Technical University of Budapest for the Bulgarian State Railways for testing their computerized interlocking system.