An ILP for scheduling rolling stock maintenance activities under operational and logistical constraints

With the expected increase in railway transportation demand, the scheduling of preventive maintenance activities is becoming a critical issue in many industrial sectors, particularly for rolling stock. To address this difficult problem, we proposed an optimisation of maintenance scheduling based on reliability aspects, in order to accurately assess the cost of maintenance by also integrating the cost of corrective maintenance. Scheduling consists of determining the optimal date, for each maintenance activity associated with a specific component, when a train unit switches from operational to maintenance status to perform the activity. Furthermore, the proposed modeling considers the condition of the train when it should be out of service due to exceeding the imposed maintenance date. The maintenance schedule also considers the capacity limits of the maintenance centers as well as the resource requirements of the activities. The proposed formulation is based on an integer linear programming (ILP) approach, which is solved on randomly generated instances using a commercial solver.