A model for medium-term operations planning in an intermodal rail–truck service

This paper describes a model developed for medium-term operations planning in an intermodal rail–truck system. It was motivated by the need to redesign such systems to produce (1) more reliable service, (2) multiple service classes, and (3) better equipment and facility utilization. The model is an integer linear program, which is computationally difficult to solve. A heuristic procedure was developed which provides excellent solutions, generally within 1% of the known optimal solution to the relaxed (non-integer) problem. Thus the model and heuristic could be used on large networks. Uses of the model and possible extensions are briefly discussed.