Contracting Timetable Information Networks ⋆

During the last years, impressive progress has been achieved in the field of speed-up techniques for DIJKSTRA’s algorithm. Due to the availability of road networks, most speed-up techniques were developed for such networks. The fastest known techniques use contraction, a procedure that reduces the graph size, in order to gain their impressive speed-ups. However, in a recent work it was observed that those techniques yield a much worse performance when applied on time-expanded networks resulted from railway timetable information data, and conjectured that this might be due to the contraction routine. In this work, we present a new contraction routine tailored to time-expanded graphs representing railway timetable information. This is a first step towards the adaption and development of contraction-based speed-up techniques to these networks.