Comprehensive Optimization of a Metro Timetable Considering Passenger Waiting Time and Energy Efficiency

Reducing passenger waiting time and energy consumption through train scheduling can have a great impact on improving the quality of service and energy efficiency from an operational view. However, there is a lack of studies of timetable optimization for connecting different modes of rail transit while considering the passenger transfer demand. This research considered the connection between a one-direction metro timetable and a railway timetable. Based on the spatiotemporal distribution of the demand of passenger flow, the optimal metro timetable for transfer passengers in different planning horizons was determined by optimizing and adjusting the following headway, running time of sections, and dwell time at stations. We proposed a multi-objective programming model consisting of three objective functions to minimize energy consumption, passenger waiting time at stations and the waiting time of transfer passengers at transfer stations. We used a fuzzy multi-objective optimization algorithm to solve the multi-objective programming model and added different weight factors to the three objective functions to obtain three optimal timetables, namely, timetables for energy-savings (E-timetable), passenger waiting time (WT-timetable), and transfer passenger waiting time (TWT-timetable); these timetables maximize energy efficiency, the quality of passenger service, and the transfer efficiency respectively. Finally, two practical cases based on real-world operational data were used to demonstrate the performance of the proposed models. The results showed that the three optimized timetables met the different requirements of the decision-makers; the combined use of the three optimized timetables can be used to guide actual operations.