Planning and optimizing train loading operations in container terminals: A comparison between a mathematical model and a greedy heuristic

The increase of rail freight transportation is highly desirable, both for its capacity of moving bigger quantities of cargo with respect to road transport and for its reduced environmental impact. Among the different decisional aspects related to rail transportation planning, in this paper the problem of optimizing train loading operations in container terminals is addressed. In such terminals, the timing of the train loading process is crucial, together with the necessity of maximizing the number of containers to be loaded on trains. Consequently, this has an impact on the economy of rail transport and, therefore, on its competitiveness. An optimization problem is stated for determining the optimal train loading plan in order to maximize the number of containers loaded and minimize the set-up operations necessary for adapting wagons configurations to the various containers to be loaded. In addition to an optimal approach, a heuristic procedure is defined for solving the proposed optimization problem. The comparison among the two approaches shows very close performances both in terms of computational time and quality of the obtained solutions. From a practical standpoint, this research could provide a decision support system to real container terminal managers, in order to help them speeding up and optimizing rail operations and, consequendy, increase the rail quota and decrease operative costs.