What Are New Insights Using Optimized Train Path Assignment for the Development of Railway Infrastructure?

Abstract

The train path assignment optimization algorithm generates an optimal solution for freight train service applications by connecting available slots between several construction nodes without conflicts. This method is not only used for a real timetable e.g. for the following year but also for timetable-based development of railway infrastructure in long-term scenarios. However, for infrastructure development the actual slot connections are not the main concern in this planning step. The railway infrastructure company rather wants to detect bottlenecks in the infrastructure and needs to get evidence for necessary developments of its railway network. By presenting results of a real world German railway network’s test case, this paper shows which bottlenecks can be derived from an optimized slot assignment and which measures (in timetable and infrastructure) could eliminate the detected bottlenecks. Necessary key figures for discovering bottlenecks will be introduced, too. It is shown that shadow prices of the developed column generation method are a good indicator for the identification of bottlenecks. For the first time with the comparison of different scenarios one can deliver a clear monetary benefit for the removal of a single bottleneck, e.g. the revenue advantage of an additional track for dwelling of freight trains. Hence, using the developed optimization algorithm for train path assignment leads to new useful insights for a railway infrastructure company to develop its railway network.