Trains and train coupling

A full representation of rail services must address additional complexities not found in other modes, such as trains that join or split, and TRAIN NUMBERs that are distinct from the identifiers of SERVICE JOURNEYs and may change over the course of the journey.

EPIP includes in its scope only a minimal representation concerned with the labelling of journeys and JOURNEY PARTs. It also allows the availability of FACILITies to be limited to a JOURNEY PART.

A SERVICE JOURNEY may be broken down into a number of JOURNEY PARTs, each with its own TRAIN NUMBER. JOURNEY PARTs from different SERVICE JOURNEYs may be coupled together with a JOURNEY PART COUPLE to indicate that they are joined in a single train for that section of their running. The same TRAIN NUMBER may be given to both SERVICE JOURNEYs by assigning it to the JOURNEY PART COUPLE