An optimization model for periodic timetable generation with dynamic frequencies

We present an optimization model for generating periodic railway timetables given the line structure and the desired line frequencies, taking into account infrastructure constraints affecting headway and overtake locations. The model uses the minimum cycle time T as the objective, therefore the stability of the timetable is taken into account. The symmetries of the periodic timetable are exploited in order to reduce the search space. By repeatedly calling the optimization procedure with different line frequencies, our approach can explore the effect of frequency changes on stability.