MAINTENANCE SCHEDULING OF METRO TRAINS FOR MAXIMIZING THE AVAILABILITY OF TRAINS (CASE STUDY OF TEHRAN METRO LINE 2)

Maintenance scheduling of trains in the metro is of particular importance for the availability of more trains, reducing train delays, and public satisfaction with the rail transportation system. The purpose of this study is to maximize the availability of trains. Also, for the research method, we use a linear scheduling model of the multi-objective mixed integer linear programming model to schedule the maintenance of Tehran's Metro Line 2 trains. The operational constraints of the model include the length of time it takes to carry out maintenance activities, the time cycles of maintenance activities, the capacity of the maintenance crew teams, and the minimum number of trains available on the line. The model consists of two objective functions, the rst objective function tries to maximize the number of maintenance activities and the second objective function tries to send a smaller number of trains to the maintenance unit daily. In order to solve the problem of scheduling maintenance of Tehran's Metro Line 2 trains, we use the innovative backtracking algorithm. According to the presented results, a 21.42% improvement can be provided in Tehran's Metro Line 2, or in other words, the accessibility of trains can be increased by 21.42%.