Schedule Coordination Method for Last Train Transfer Problem

This paper proposes a schedule coordination method for last train service in an urban rail transit system. The method offsets and perturbs the original train schedule to reduce transfer failures across different lines, and it considers the effect of schedule adjustments. The proposed problem is formulated as a mixed-integer nonlinear programming (MINLP) model. The MINLP model is equivalently transformed into a mixed-integer linear programming (MILP) model that can be exactly solved by commercial optimization solvers. A case study based on the mass rapid transit system in Singapore was conducted. The results of the case study indicate that the train schedule that is coordinated by the developed model is capable of substantially improving operational connectivity. Therefore, the model proposed in this study can be employed as a viable tool to assist with the coordination of train schedules for public transport operators.