Optimization of Wagon Flow Assignment with Transship Work for Multiple Marshaling Stations at Railroad Terminals

To improve the operation efficiency of wagon flow at railroad terminals with multiple marshaling stations, firstly based on the analysis of different types of wagon flow operations at the terminal, the mathematical model is constructed with the goal of minimizing the total costs of wagons entering and leaving a station, wagon flow reorganization, wagon assembly and transship. Secondly, according to the railroad direction and the capacity of receiving and dispatching trains at the station, an initial matching scheme of the train−marshaling station−shunting system is designed, and then the matching scheme is adjusted and tested by using the transship and disaggregation capacity. Thirdly, a double-layer coding scheme for the matching scheme of the train−marshalling station−shunting system is provided, and the group optimization of the matching scheme is completed with the asynchronous iteration updating process of the embedded replacement–disturbance–crossing operation. Finally, a simulation experiment is conducted to test the proposed model and algorithm. The experimental results show that the proposed method can complete the reasonable division of assignments for multiple marshalling stations. Five groups of test tests can obtain the matching scheme of train−marshalling station−shunting system in the calculation time of 369, 422, 516, 641 and 763 s, respectively. In the optimized division of assignments, the proportion of wagon transship in arrival wagons flow can be stabilized at 20%, so as to reduce the number of wagon transships and reduce the cost of traffic flow organization.