Rijtijdspeling in treindienstregelingen

Abstract

Commissioned by the Dutch Railways Operation (NS Reizigers) research has been conducted on the possibilities to better incorporate energy-efficient train operation into the timetable. The motivation for this research is based on the fact that energy-efficient operation is not yet optimally included in the timetable design. This is because of the fact that the running time supplement is not optimally divided. Running time supplement or slack time is the running time above the minimal running time between two timetable points. The objective of the research is to develop a model which determines the optimal coasting point and the optimal cruising speed for trains and the associated running time supplement distribution; taking into account the desired robustness, the possibilities for energy-efficient operation and the desired punctuality during the execution of the timetable. The behavior of a train is described by four driving regimes: acceleration, cruising, coasting and braking. With these driving regimes this study considers two driving strategies: time optimal and energy-efficient. The time optimal driving strategy requires a train to drive as fast as possible from A to B using the driving regimes acceleration, braking and possibly cruising. The energy-efficient driving strategy requires a train to drive also from A to B using as less as possible traction energy given the available time from the timetable. The coasting regime is an important part in this strategy. The energy-efficient driving strategy is determined by the optimal control theory. The algorithm which is applied in MATLAB determines the energy-efficient driving strategy by calculating the optimal coasting point and the optimal cruising speed given the time from the timetable. The model has been applied on the section Utrecht Central – Rhenen for sprinter train series 7400. The results of this research show that there are yearly energy savings possible of almost € 26.400 if the energy-efficient driving strategy is used instead of the UZI (‘Universeel Zuinig rijden Idee’) method of NS Reizigers. Moreover the results show that using a uniform distribution of the running time supplements leads to extra energy savings and an improvement for the punctuality compared to the method of tightening the timetable. Tightening the timetable means that the running time supplements are placed as much as possible short before stations where the punctuality is measured. These yearly extra savings which are possible by the uniform distribution instead of the current slack time are almost € 44.000 for the energy-efficient driving strategy and are almost € 27.500 for the UZI method on the total section.