scope:

This guidance applies to LU maintained equipment only.

This guidance applies to 10kHz overlay rail circuits, and to de-energised rail circuits using blockjoints. It does not apply to mechanical treadles, electromagnetic position detectors or axle counters, which are covered in T0543 'Train detection systems'. It is to be used when devising maintenance regimes by the Asset Steward.

Note: The functions and performance criteria for track circuit based train detection systems are detailed in T0543 'Train detection systems', and their maintenance requirements are specified in G199N 'Maintenance of track circuits'.

Purpose

This document provides guidance for the minimum maintenance requirements for rail circuits and associated equipment used on London Underground (LU).

Note: Rail circuits are safety critical assets, typically used to enable the safe clearing of signals or the safe releasing of routes.