Equipment and systems forming part of, or providing input to, the Signalling
Systems to detect, either:
• the presence or absence of vehicles within the limits of a track sectionA portion of railway track having fixed boundaries and for which the Train Detection System provides information on its state of occupancy to the Signalling Sys..., or
• that a train has reached, is passing or has passed a specific position.
Where required, a train detection systemEquipment and systems forming part of, or providing input to, the Signalling Systems to detect, either: • the presence or absence of vehicles within the limit... may additionally detect the
direction in which a train is travelling.