Robust Railway Infrastructure
Final Report Abstract
Railroad infrastructure expansions are usually planned based on demand forecasts and political requirements and taken as a given for further planning steps such as line or timetable planning. However, this leads to difficulties in creating attractive timetables if travel times between stations are not optimized or the capacities on lines and nodes are insufficient. Therefore, more and more railroad infrastructure companies are developing strategic timetables and planning infrastructure measures based on them. These strategic timetables contain network-wide optimized travel times and connections and often follow the principles of an integral interval timetable. However, due to the long time span between creating and implementing a timetable concept, strategic timetables are subject to uncertainties, as the circumstances can change over time. To support the process of strategic timetable planning and the derivation of infrastructure measures, optimization models for timetable-based infrastructure planning, which is robust against changes in the strategic timetable, have been developed within the project "Robust Railway Infrastructure". Based on the network design problem, two optimization models were formulated that minimize infrastructure costs assuming a given (strategic) timetable is feasible. Costs are incurred for the construction of tracks and for the reduction of running and train times. The timetable data contains the trains to be scheduled with time barriers and specifications for frequencies and transfers between several trains. The two models differ in the modelling of the temporal aspect of the timetable: on the one hand, the departure and arrival times of the trains are modelled as variables, on the other hand, they are integrated into a time-expanded graph. Both models were tested and compared for different use cases. Robustness to changes in the strategic timetable was achieved by modelling different timetable concepts as discrete scenarios and allowing the optimization models to compute networks covering multiple scenarios. In addition, variations in demand within a scenario were modelled using optional trains. In applying the models, the sensitivity with respect to the input parameters was considered and a procedure was implemented to determine the residual capacity of the infrastructure under the respective timetable. The models developed during the project demonstrate the feasibility of minimum-cost and robust infrastructure planning based on a strategic timetable. Currently, they are applicable to regional railroad networks. To be able to solve the model for larger networks, approaches for decomposition procedures were formulated, which can be deepened and refined in further research.
Publications
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Timetable-based railway network design Abstract Book 31. European Conference on Operational Research, EURO 2021, Athens, Greece, 11-14 July 2021
Tim Sander
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Designing Railway Networks based on Timetables Book of Abstracts INOC 2022
Tim Sander
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Introducing an Optimization Model for Timetable Based Railway Network Design
Tim Sander & Karl Nachtigall
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Modelling the Railway Network Design Problem with Capacity Expansion under Timetable constraints Abstract Book 32. European Conference on Operational Research, Euro 2022, Espoo, Finland, 3 Jul 2022 - 6 Jul 2022 261-261 (2022)
Nadine Friesen; Tim Sander; Karl Nachtigall & Nils Nießen
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Robustes fahrplanbasiertes Netzwerkdesign Eisenbahntechnische Rundschau 71(10), 16-20 (2022)
Tim Sander; Nadine Friesen; Karl Nachtigall & Nils Nießen
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Modeling Uncertainty in the Timetable-Based Railway Network Design Problem. Lecture Notes in Operations Research, 503-509. Springer International Publishing.
Sander, Tim; Friesen, Nadine; Nachtigall, Karl & Nießen, Nils
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Modelling Time in the Timetable-Based Railway Network Design Problem (Abstract) Book of Abstracts ICROMA RailBelgrade 2023
Nadine Friesen; Tim Sander; Karl Nachtigall & Nils Nießen
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Modelling Time in the Timetable-Based Railway Network Design Problem.
Nadine Friesen; Tim Sander; Karl Nachtigall & Nils Nießen
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The complexity of the timetable‐based railway network design problem. Networks, 83(2), 289-299.
Friesen, Nadine; Sander, Tim; Büsing, Christina; Nachtigall, Karl & Nießen, Nils
