On the uniqueness of operation days and delivery commitment generation for train timetables

In the 2014 finalised timetable for Sweden 314 operation days had a unique set of trains i.e. a unique traffic pattern. Despite this, the finalised timetable generally provides only one conflict resolved train path for each train, and this train path is to be used for all of the train’s operation days. Further, once the yearly timetable has been finalised train paths may not be changed, causing great inflexibility in later planning stages. Rather than finalizing entire train paths only certain characteristics of a train path, called delivery commitments, could be finalised. This allows for more flexibility in later planning stages. Delivery commitments could e.g. be arrival and departure times at important locations or the total running time, depending on the needs of the operator. In this paper we present a method for generating delivery commitments based on analyzing a yearlong timetable, called the control timetable. The control timetable is constructed using rolling horizon planning and a MIP-model that optimises the train paths for each day individually. Further, different train path characteristics are optimized for different operators. The proposed method was tested in a case study from Sweden. The results show that by constructing one train path for each individual day rather than one for the entire year the resulting delivery commitments allow for a more efficient use of infrastructure. The results also show that the proposed method allows for different train path characteristics to be optimised for different operators.