A metro train rescheduling approach considering flexible short-turning and adding backup trains strategies during disruptions in the case of the vehicle breakdown.

A heavily congested metro line is vulnerable to unexpected disruptions which often cause train delays and other negative impacts. This paper firstly proposes a train rescheduling optimization model in the case of the vehicle breakdown on a metro line. The objective of this optimization model is to minimize the deviation from the original scheduled timetable and the number of canceled train services. Moreover, the train timetable rescheduling (TTR) and the rolling stock rescheduling (RSR) problems are simultaneously considered in this paper. Efficient rescheduling strategies including flexible short-turning and adding backup trains are particularly formulated into the model. By introducing additional constraints and the big-M variable, the optimization model is further transformed into an integer programming (IP) model, which can be efficiently solved by CPLEX optimizer. Finally, a case study with the real-world data set of the Beijing Fangshan metro line is carried out to verify the effectiveness of the rescheduling model.