A reliability analysis of railway switches

Switches and crossings (S&C) are critical elements on railway networks. Any failure of S&C usually leads to train delays and cancelations having a negative impact on the quality of service delivered, railway safety and also operating costs. S&C is a multi-component system and to enable proactive prevention of S&C unit faults, with their undesirable consequences, the ability to predict problems at component level is needed. This paper describes the derivation of lifetime distributions of individual S&C components based on field data collected. Maintenance was identified as a potential contributor towards increased frequency of reported S&C faults. The outcomes of the analysis and lifetime distributions for the elements of the switch units provide a means of predicting the expected number of maintenance activities, and associated costs for these units over any specified period of time. They provide an essential input to the optimisation of maintenance in developing an asset management strategy.