Timetabling and assignment problems in railway planning and integer multicommodity flow

We reconsider the successful approaches that we adopted in the past to solve Train Timetabling, Train Platforming, Train‐Unit Assignment, and Crew Assignment problems arising in railway planning. We try to unify these approaches under a common framework, noting that they are all formulated as variants of a fairly general version of integer multicommodity flow, and discussing the solution methods and modelling issues that we found most relevant.