Freight Service Design for the Italian Railways Company

摘要

In this paper, we present a mathematical model to designthe service network, that is the set of origin-destinationconnections. The resulting model considers both full and emptyfreight car movements, and takes into account handling costs. Morespecifically, the model suggests the services to provide, as wellas the number of trains and the number and type of cars travelingon each connection. Quality of service, which is measured as totaltravel time, is established by minimizing the waiting time of carsat intermediate stations.Our approach yields a multi-commodity network design problem withconcave arc cost functions. To solve this problem, we implement atabu search procedure which adopts ``perturbingu27u27 mechanisms toforce the algorithm to explore a larger portion of the feasibleregion. Computational results on realistic instances show asignificant improvement over current practice.