The wheel–rail contact relationship has a great impact on the security and reliability of metro vehicles in service. In particular, wear modeling and maintenance optimization of the wheels play significant roles with regard to both safety and cost. However, it is difficult to provide a satisfactory model of wheel wear because of the open nature of real wheel–rail systems and the constantly varying environmental conditions in which they operate. Historically, re-profiling, which also has its limitation to some extent, was adopted as a common strategy to restore the original profiles of the worn wheels. Acknowledging that re-profiling is not the only strategy for dealing with wheel wear, the authors of this study have developed a more advanced optimization approach that includes two more strategies, namely, vehicle turning and multi-template use, to give as near an optimal solution as possible. Vehicle turning refers to the reversal of the vehicle’s orientation on the rail, whereas multi-template use refers to the situation where different re-profiling templates are used alternately. In this paper, re-profiling, vehicle turning, and multi-template use have been discussed separately. Then a hybrid optimization strategy for the maintenance of the wheels of metro vehicles has been proposed, with the aim of maximizing the wheel life while minimizing the relevant costs. An initial case study on the Shanghai Metro system shows that the proposed approach is able to provide a more reasonable solution for the optimization of the maintenance strategies.
A Queuing Network Based Optimization Model for Calculating Capacity of Subway Station
