Efficient design of freight train operation with double-hump yards

This work provides a new methodology to solve the rail freight train service design problem, with the following distinctive characteristics: (1) service costs, traveling distances and capacities of different service paths in each double-hump yard are explicitly considered; and (2) the direction of train service movement through double-hump yards are determined. The problem is formulated as integer programming, aiming at minimizing the total cost of cumulative train service cost, service cost and distance-driven cost. Three examples of different scales are solved using tabu search algorithm. The results and process of the algorithm, compared with exact solutions determined by the ILOG Cplex software, demonstrate high computational efficiency and solution quality. A small- and a large-scale case study in China are used to examine the model. The results show that the methodology used could save between 8.3 and 40% of the number of shifted service cars compared with the best-known published model.