Micro-simulation based analysis of railway lines robustness

Railway Undertakers and Railway Infrastructure Managers have a variety of parameters to measure robustness of timetables: this paper examines empirical data collected from Nederlandse Spoorwegen on the heavily occupied railway line between The Hague and Rotterdam in The Netherlands. The results show that the robustness indicator examined are affected by infrastructure changes in different ways.

A micro-simulation of the line is used to determine the robustness of different railway infrastructure scenarios measuring the capacity consumption, as well as the share of trains affected by amount of delays in case of disturbance. The individual robustness indicators’ sensitivity to primary delays is estimated through regression analysis and either the second derivative or the amplification as a function of the train frequency.

A skimming method is used for the selection and simulation of a delayed train course that can represent the total train delay along the line. Dispatching measures in case of disturbance are excluded by applying First-In First-Out rule in simulations. The benefits of modifications to the track infrastructure, the timetable, and the signaling system, in terms of consecutive delays reduction, are estimated by inserting a range of primary delays.

The research highlighted the need of a step further than currently planned in the infrastructure development to improve the line’s robustness. This is significant for the relationship between IMs and RUs, as the same infrastructure or planning/scheduling improvements could be measured in a different way from each other contractor, with economic impact on the infrastructure use agreements.