Last train timetabling with transfer accessibility in metro networks: integer linear programing model and schedule-based transfer network

Abstract

Last train timetable plays an important role in actual operation of metro systems, especially in big cities. Appreciable transfer passengers rely on last train connections to reach their destinations, which requires a coordinated last train timetable. This study is devoted to dealing with the last train timetabling problem in metro networks, and proposes an integer linear programing model to coordinate last train connections at transfer stations to improve the transfer accessibility in terms of served transfer passengers and effective last train connections. Several measures at the planning level are used to guarantee feasibility of the optimized last train timetable when applied in practice. Then, the schedule-based transfer network and pre-process method are presented to shrink the scale of binary variables, which can expedite the solution process when solving problems in large-scale networks. Finally, some experiments based on the Qingdao metro network are carried out to verify the effectiveness of the timetabling method, and results show that dwell time and service ending time have direct influence on network accessibility. Comparison analyses show that the proposed model is able to generate a coordinated enough last train timetable with higher transfer accessibility and better practicality, which can provide support for operators to improve the last train service in a metro network.