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Design of the Safety Control Logic for Railway Stations Based on Petri Nets

The control logic in the traditional interlocking depends on human's experience, lacking a unified generation and verification method. In this paper, we use Petri nets to model railway stations and then obtain the mathematically optimal control logic to ensure safety and liveness. First, we use a modular method based on its devices including track segments, signals and switches. The interlocking condition is formulated as a set of linear constraints. According to the supervisory control theory, monitor places can be calculated to enforce the constraints. Finally the control logic derived from the monitor place is proven maximally permissive. Finally we take the simulation to investigate the performance of the control logic.