Modeling and hazard analysis of railway station protection system based on stochastic petri nets

The applicable CENELEC standards as well as the safety directive of the European parliament expect defining safety requirements for railway control functions and system constituents according to the global safety targets which are to be used for quantification of tolerable risk of the railway operation. This target is achieved by holistic modeling, risk definition and hazard analysis of all the influencing factors of railway operation risk based on a single stochastic Petri nets description method. The hazard analysis is achieved based on railway traffic process, implementation of control system components and its dependability. As an example, the station protection system is used to describe the detailed process of modeling, analysis and simulation. Simulation results show stochastic Petri net can be used to finish the apportionment of the safety targets to components of control systems.