The main objective of the present standard is to present the reference data model for public transport, based on: — the reference data model, EN 12896, known as Transmodel V5.1; — EN 28701, known as IFOPT; incorporating the requirements of: — EN 15531-1 to -3 and CEN/TS 15531-4 and CEN/TS 15531-5, Service interface for real-time information relating to public transport operations (SIRI); — CEN/TS 16614-1 and CEN/TS 16614-2, Network and Timetable Exchange (NeTEx), in particular, the specific needs for long distance train operation. A particular attention is drawn to the data model structure and methodology: — the data model is described in a modular form in order to facilitate the understanding and the use of the model; — the data model is entirely described in UML. In particular, a Reference Data Model kernel is described, referring to the data domain: — network description: routes, lines, journey patterns, timing patterns, service patterns, scheduled stop points and stop places. This part corresponds to the Transmodel V5.1 network description extended by the IFOPT relevant parts.