An Optimal Reprofiling Policy for High-Speed Train Wheels Subject to Wear and External Shocks Using a Semi-Markov Decision Process

• Published in: IEEE transactions on reliability Vol. 67; no. 4; pp. 1468 - 1481
• Main Authors: Mingcheng, E., Li, Bing, Jiang, Zengqiang, Li, Qi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Condition monitoring; Degradation; External shocks; High speed rail; Inspection; Iterative algorithms; Iterative methods; Maintenance costs; Maintenance engineering; Maintenance management; Markov analysis; Markov chains; Optimization; policy-iteration algorithm; Rail transportation; Railroad wheels; reprofiling policy; Safety; semi-Markov decision process (SMDP); Service life; Vehicle wheels; Wear; Wheels
• ISSN: 0018-9529; 1558-1721
• DOI: 10.1109/TR.2018.2870276

Wheels are one of the three components of rail vehicles that are most affected by wear, having significant implications on safety and comfort. For the safety of vehicles, maintenance activities are needed for worn wheels to ensure their normal geometry, where reprofiling plays the most important role in maintenance. How to reprofile wheels scientifically and economically has become a vital issue, which needs to be solved in the field of wheel maintenance. This study focuses on high-speed train wheels and proposes a dynamic reprofiling policy based on condition monitoring at equidistant discrete time inspections. The problem is modeled in the framework of a semi-Markov decision process considering both wear and external shocks. The objective of the maintenance model is to minimize the long-term expected cost per unit time. We apply a policy-iteration algorithm to determine the optimal reprofiling policy. To demonstrate the model's effectiveness, actual degradation data on high-speed train wheels are used as an illustration. The results show that the dynamic reprofiling policy reduces wheel maintenance costs and extends their service life, also ensuring wheels' safety.