Energy-Efficient Train Control under Relaxed Timetable Constraints

This paper presents an energy-optimal scheme to compute the speed trajectory for a single train over multiple stops subject to a relaxed timetable. Motivation for such an approach is that a train operator cannot modify the timetable itself, but can compensate for its suboptimal design (from the energy consumption perspective) by allowing variation in the strict station timings. A convex optimization approach is devised to allocate time supplements among the interstation segments to achieve energy optimality. The proposed approach is demonstrated on an example of real timetable and simulated train dynamics. Comparison with the timetable-adhering solution revealed energy savings of more than 26 % when symmetrical 15-second relaxation around the timetable is allowed, demonstrating the energy-saving potential of the proposed proof-of-concept solution.