Rolling Stock Rostering Optimization Under Maintenance Constraints

This paper presents an integer programming formulation for integrating maintenance planning tasks in the railway rolling stock circulation problem. This is a key problem in railway rostering planning that requires to cover a given set of services and maintenance works with a minimum amount of rolling stock units. An additional objective is to limit the number of empty rides. The constraints of the rolling stock rostering problem require that different types of maintenance operations must be carried out for each train periodically. The various maintenance tasks can only be done at a limited number of dedicated sites. This is achieved by a graph theoretical approach that combines the scheduling tasks related to train services, maintenance operations and empty rides. Preliminary computational results on real-world scenarios show that this integrated approach can reduce significantly the number of trains and empty rides when compared with the current rolling stock circulation.