Scientists from TU Dresden and RWTH Aachen University jointly develop optimisation models for the planning of railway networks.

As part of the DFG project "Robust Railway Infrastructure", the Chair of Traffic Flow Science of the "Friedrich List" Faculty of Transport and Traffic Sciences at TU Dresden developed mathematical optimisation models for the robust, timetable-based planning of railway networks together with the Institute of Transport Sciences of RWTH Aachen University. As part of a lecture on 4 April 2023 at TU Dresden, the doctoral students working on the project, Nadine Friesen, M. Sc. (RWTH Aachen, photo: 2nd from right) and Dipl.-Ing. Tim Sander (TU Dresden, photo: 2nd from left), presented their results together with Prof. Nils Nießen (RWTH Aachen, photo: right) and Prof. Karl Nachtigall (TU Dresden, photo: left). The event was held on a hybrid basis so that non-university participants, for example from DB Netz AG, could also take part.

Timetable-based infrastructure planning describes the question of how much infrastructure is necessary to implement a given timetable concept. For this task, an optimisation model was developed for the first time as part of the project. This was subsequently extended to make the calculated networks robust to changes in the given timetable. The representation of the uncertainties in the demand data is done by discrete timetable scenarios as well as by optional trains.

Both institutes involved developed their own model variant, which differ in essential modelling concepts. The model developed in Dresden uses variables to represent temporal processes, while the model designed in Aachen works with time-expanded graphs. The use of both approaches enables a comparison of the methods. Initial tests show that the model with time variables has advantages in terms of performance, but the model with time-expanded graphs offers better possibilities for model extension.

In addition to the presentation at TU Dresden, interim results have already been presented at several conferences, including EURO 2022, TRISTAN XI, OR 2022 and RailBelgrade 2023. Publications in journals are also in preparation.


Dipl.-Ing. Tim Sander
Research Assistant
Chair of Traffic Flow Science
"Friedrich List" Faculty of Transport and Traffic Sciences, TU Dresden