In order to evaluate the impact of future improvements in a rail transport systems, it is important to produce a new feasible timetable for all trains in each new scenario. Typically this includes changes in the infrastructure, but also changes in the composition/frequency of trains.
Strategic train timetabling is the task of producing new tentative timetables for these "what-if" scenarios. Unlike the more standard train timetabling, strategic timetabling can usually overlook some operational aspects, such as crew and rolling stock scheduling. On the other hand, each strategic timetable is completely new (and usually very different) from the others, eliminating the possibility of warm starting the solution process by exploiting an existing one.
We consider the case of quasi-periodic timetables, that are timetables where certain subsets of trains need to start at almost (rather than precisely) the same minute of every period (e.g., hour). In collaboration with Jernbanedirektoratet, we developed a mixed-integer linear program for strategic quasi-periodic train timetabling and we produced 8 different feasible timetables on 8 different scenarios for an important railway line in Norway.