scope:

This general specification covers the design and manufacture of Track Voltage Relay (TVR ) systems, based on solid state technology, for use on 750V DC third rail electrification systems. The system specified in this document are to be used for indicating the state of energisation of a track section and to trip the associated DC circuit breakers in the event of a fault that creates low voltage conditions.

Detailed information regarding the number, disposition, specific installation details and other relevant information covering the requirements of the relays, is included in the associated procurement specification.

The term TVR used in this specification shall be taken to mean a Process Logic Controller (PLC ) based system that measures the track voltage and depending on the measurement, operating various outputs according to the program contained within the system.