Design of Running Grades for Energy-Efficient Train Regulation: A Case Study for Beijing Yizhuang Line

In the practical operation of the Beijing metro systems, cyclic timetables are used, where the dwell times for all train services are the same for a station during the whole day. Since the passenger demand in peak hours is much higher than that of the off-peak hours, the scheduled dwell times for train services in the off-peak hours are in general a few seconds or even more than 10 seconds longer than the required (or valid) dwell times. The difference between the scheduled dwell time and the valid dwell time is called the dwell time supplement. A train regulation approach is proposed to use the dwell time supplements sufficiently, where the dwell times for train services in the off-peak hours are shortened due to the small number of boarding and alighting passengers. The dwell time supplements are then added to the running times of the next interval (i.e., the section between two consecutive stations). The resulting longer running times can reduce the energy consumption of the metro line. Based on the distribution of the dwell time supplements, the running times corresponding to different running grades in Automatic Train Supervision (ATS) systems are determined for different intervals to minimize the total energy consumption during a day. Based on the operational data, a case study for the Beijing Yizhuang line is presented to illustrate the effectiveness of the proposed approach.