Delay resistant line planning with a view towards passenger transfers

The line planning step, as part of the public transportation planning process, is an elementary problem. When generating public transportation systems in a conventional fashion, the line planning problem is one of the first to solve. Hence, subsequent problems rely on the solution of the line planning problem. Line planning has been studied from various perspectives and is understood very well. Still, the effect of this planning step on to the next ones has only received minor attention. In this paper, we study the effect of transfers on the delay resistance and propose a line planning model which provides a good basis for a delay resistant transportation system. To this end, the concept of preferable paths from the direct travelers line planning model is further extended. The model includes the routing of passengers in order to minimize passenger transfers. A column generation approach is shown to properly solve the proposed model. As such, this is the first line planning model which detailedly routes the passengers and is still tractable on realistically sized instances. Finally, it is shown that minimizing the passenger transfers at the line planning stage contributes to an increasing delay resistance in the public transportation system.