Optimization of Urban Rail Transit Train Stock Utilization under Re-coupling Operation Mode

［Objective］ Re-coupling operation mode can effectively improve the matching degree between the passenger flow and the transport capacity of urban rail transit, while it also poses challenges to the formulation of the train stock utilization plan. Therefore, it is necessary to conduct research on the connection between the train stock and different marshalling train trips under this mode. ［Method］ By analyzing the cha-racteristics of urban rail transit train stock utilization under the re-coupling operation mode and the connection situation of the train stock during the transition period from peak to off-peak passenger flow, aiming at minimizing the number of train stock in use and the connection time cost, and ensuring the balance of train stock utilization, relevant constraints such as the uniqueness of train service connection, the consistency of train stock, maintenance plans, regular node connections, and connection of coupled train service nodes are comprehensively considered. The MTSP ( multiple traveling salesman problem) is introduced to construct an optimized train stock utilization model during the transition period from peak to off-peak passenger flow in urban rail transit. Moreover, a MOFA (multi-objective firefly algorithm) based on MCS (multiply cooperative strategies) is designed. In the case study of a certain urban rail transit line with significant imbalance of passenger flow in different periods, the feasibility and rationality of the above optimized model are verified. ［Result & Conclusion］ The optimized train stock utilization scheme of urban rail transit under the re-coupling operation mode can reasonably optimize the connection between different marshalling train trips and reduce the operation costs for enterprises.