scope:

The guidance covers several types of 'traditional' track circuits used on LU and should be used by those engaged in preparation of maintenance documentation (e.g. work instructions). The guidance should be used when preparing maintenance regimes and producing associated documentation (e.g. Method Statements).

Note: This guidance does not address the maintenance of rail circuits such as 10kHz overlay rail circuits or de-energised rail circuits using blockjoints - these are the subject of guidance G199Y 'maintenance of rail circuits. Basic functional tests for FS series Jointless Track Circuits (JTC) are described, but installation documentation, Operation and Maintenance manuals and Work Instructions should be consulted for detailed setting up and maintenance instructions for the particular JTC involved.

Purpose

This document provides guidance for the minimum maintenance requirements for a number types of track circuits and associated equipment used on London Underground (LU).

Note: Not all types of track circuits in use on London Underground are covered in this guidance. Whether a particular type of track circuit is covered or not, reference should always be made to Work instructions, installation documentation and Operation and Maintenance manuals.