A Subway Train Timetable Optimization Approach Based on Energy-Efficient Operation Strategy

TLDR

Rising energy costs and environmental concerns have driven attention to train energy‑efficient operation techniques that reduce operating costs and consumption. This study aims to optimize an integrated timetable that simultaneously schedules train arrivals and determines speed profiles. The authors formulate an analytical model for the optimal speed profile at fixed trip times, devise a numerically optimal algorithm to allocate total trip time across sections, extend it to produce an integrated timetable, and validate it with examples from Beijing Yizhuang subway data. Simulations demonstrate a 14.5 % energy savings for the entire route and a 0.15‑second computation time, indicating suitability for real‑time automatic train operation control.

Abstract

Given rising energy prices and environmental concerns, train energy-efficient operation techniques are paid more attention as one of the effective methods to reduce operation costs and energy consumption. Generally speaking, the energy-efficient operation technique includes two levels, which optimize the timetable and the speed profiles among successive stations, respectively. To achieve better performance, this paper proposes to optimize the integrated timetable, which includes both the timetable and the speed profiles. First, we provide an analytical formulation to calculate the optimal speed profile with fixed trip time for each section. Second, we design a numerical algorithm to distribute the total trip time among different sections and prove the optimality of the distribution algorithm. Furthermore, we extend the algorithm to generate the integrated timetable. Finally, we present some numerical examples based on the operation data from the Beijing Yizhuang subway line. The simulation results show that energy reduction for the entire route is 14.5%. The computation time for finding the optimal solution is 0.15 s, which implies that the algorithm is fast enough to be used in the automatic train operation (ATO) system for real-time control.