Specific case

Any part of the rail system of the Contracting States which is indicated as a special provision in the UTP, either temporarily or definitively, because of geographical, topographical or urban environment constraints or those affecting compatibility with the existing system. This may include in particular railway lines and networks isolated from the rest of the network, the loading gauge, the track gauge or space between the tracks as well as vehicles strictly intended for local, regional or historical use, and vehicles originating from or destined for third countries.