Optimization of subway train operation plan considering online coupling and decoupling scenarios

To address the uneven spatial and temporal distribution of passenger flow in urban rail transit, the optimization problem of train operation plans for full-length and short-turn routes under online coupling/decoupling scenarios was investigated. For a rail line with lower passenger demand at both ends and higher demand in the middle, the minimization of passenger waiting time and train travel kilometers was set as the objective. The departure frequency, train composition sizes for full-length and short-turn routes, and the selection of short-turn stations were defined as decision variables. Considering constraints such as train size, load factor, and passenger flow, an integer programming optimization model for the train operation plan was formulated. With a metro line in a certain city as a case study, the model was solved using a two-stage solution algorithm and the CPLEX solver. The results indicate that passenger waiting time and train travel kilometers are reduced by 20.83% and 30.09%, respectively, which significantly improves the matching degree between train capacity and passenger demand.