A Colored Petri Net model for railway track maintenance with two-level inspection
Résumé
Track fault may cause the derailment and it is one of the major contributors to railway maintenance costs. Gauge spread is one of the track faults. Maintenance and speed restriction should be taken according to the inspection results. Visual Inspection (VI) can only detect poor fastening and static gauge spread. Train Recording Vehicle (TRV) detects the loaded gauge spread. The inspection frequencies are required in Standards, but they should happen at a greater frequency if the recommendations are insufficient. Two inspection schemes are introduced for a railway section. One scheme considers that VI and TRV are periodic; another assumes that TRV interval depends on the number of identified defects. In this paper we propose a risk and maintenance model based on a hierarchical Colored Petri Net (CPN) for a railway section, since CPN is flexible enough to model the component deterioration process and the different inspection schemes. The CPN model considers not only the maintenance process for observed component states but also the accident scenarios. According to Monte Carlo simulation results, the model can be used to evaluate the inspection policies.