Rolling stock door system reliability improvement using maintenance optimisation

The maintenance of rolling stock is a major task because an in-service failure causes delays and passenger dissatisfaction. This paper focuses on the door system of the Class 158 Diesel Multiple Unit DMU train fleet. The door system consists of several functionally dependent components and is operated in-service continuously and is only monitored at discrete time points. The doors have a combination of serial/parallel systems consisting of over 100 components and the component lifetimes are Weibull distributed which implies that they are aging with time. A failure analysis of the door system is conducted using the reliability centred maintenance approach and an attempt is made to optimise the door maintenance practices given that they have been operating for certain number of periods. The door systems consist of several worn and aging components and are considered to be stochastically independent. Cost effective preventive maintenance optimisation is performed using specialist simulation software, which involves incorporating the average number of door components replaced over some finite horizon. A numerical assessment of the door components is conducted and a piecewise Deterministic Markov Process model is proposed in an attempt to optimise a preventive maintenance strategy of the doors.