Long-term fleet management for freight trains: Assessing the impact of wagon maintenance through simulation of shunting policies

The optimization of shunting operations has been recognized as a cost-effective measure for rail companies, but its impact on rolling stock management has not been fully explored. Previous research on shunting operations has often focused on operational decisions, neglecting the effect of maintenance scheduling activities in an integrated approach. Our study aims to examine the long-term effects of mileage-based maintenance on freight train management and its impact on shunting operations and fleet management. We propose 4 Shunt-In policies based on practitioners' criteria that describe the wagon allocation to outbound trains based on both mileage and trajectories-based shunting criteria. To evaluate the methodology, we conduct simulations using a projected timetable from 2020 to 2040 of the freight services at the Bettembourg Multimodal Terminal in Luxembourg. The results are compared against a theoretical No-Maintenance scenario to assess the underestimation's magnitude. Our findings show that mileage-based maintenance has a significant impact on various aspects of freight management and that the choice of wagons in an outbound train can result in up to 11% increase in the number of shunting operations, as well as high underestimation in terms of expected fleet size and average mileage to be performed by the rolling stocks.