Optimal model of timetable under the influence of train speed on the utilization rate of regenerative braking

Abstract

With expanded development of subway systems, regenerative braking energy utilization has been intensively studied from a timetable synchronize point of view. Yet, even successful modeling approaches such as those based on regenerative braking technique still do not fully take into account the fact that at lower than threshold speed, no energy can be utilized. To achieve a better performance on energy-efficient operation with the actual problem, this paper formulated a timetable rescheduling model (TR model) to optimize the timetable by maximizing the overlapping time between accelerating and regenerative braking actions of trains in the same substation with the consideration of regenerative braking process. We design a genetic algorithm (GA) to solve the model and present some numerical experiments based on the actual operation data of Beijing Yizhuang subway line in China. It is shown that the model can reduce the energy consumption by 25.3% compared with the current timetable. In addition, numerical experiments show that the dwell-time and lower limits of headway have a strong effort on regenerative energy utilization.