Integer Constraints for Train Series Connections

The scheduling of train services is subject to a number of constraints describing railway infrastructure, required train services and reasonable time-intervals for waiting and transits. Timetable planners at Dutch Railways are nowadays supported by a software tool, called CADANS, which produces a feasible timetable on an hourly basis. In this paper, connection requirements between train series are written in the format of the CADANS model. It turns out that this leads to nontrivial combinatorial scheduling issues.