Optimal planning of order–based operations for intermodal freight transportation

In this paper, a planning problem is analysed for a consolidation transportation system in order to serve different transportation requests (i.e., orders) with different origins and destinations and different characteristics. The considered transportation system is a railway network provided with innovative terminals (where handling operations are realized very much faster than in traditional terminals). Therefore, a box can in general be loaded on different trains before reaching its destination. This planning problem is faced at two decisional levels, corresponding to the off–line planning and the on–line monitoring and control of the system. The off-line planning procedure aims at defining a detailed transportation plan in order to satisfy all requests and minimize the overall cost. This is achieved by a preprocessing analysis and, then, the solution of a mathematical programming problem. The on–line planning phase aims at facing a criticality happening during the system operation. At this purpose, a three-step procedure is devised in which the impact of the criticality is evaluated and, then, a local solution is searched; if it is not found, a global optimization procedure is run.