Model for Corrective Maintenance Scheduling of Rail Transit Networks: Application to Athens Metro

Efficient and safe rail transit (metro) operations require regularly inspected and properly maintained infrastructures. While preventive maintenance is usually undertaken following a predetermined schedule, decisions on repairs and corrective maintenance are usually scheduled ad hoc, following inspections. This paper presents a model for optimally scheduling corrective maintenance activities in a rail transit network, following their identification as part of an inspection process. An integer programming model is formulated for that purpose, aiming at minimizing passenger delay caused by reduced operational speeds on degraded rail segments and prioritizing activities in segments with intensive operations; higher train traffic and associated train loads; and under budget, staff, and other practical constraints. The model is applied for the case of the Athens, Greece, metro system and results are discussed.