scope:

This document covers RT type reed track circuits installed in single rail mode on a.c. electrified Railtrack controlled infrastructure. This also encompasses the older type 'R' equipment when installed in single rail mode where these are not fitted with step up transformers.

Purpose

The purpose of this document is to provide a methodology to demonstrate compatibility with 'RT' type single rail track circuits on the a.c. railway on Railtrack controlled Infrastructure. This is achieved by:

• Providing a characterisation of the reed track circuit receiver.

• Providing a characterisation of the infrastructure.

• Providing a methodology to define the susceptibility of a given reed track circuit.

Combining these elements will enable a full characterisation of a reed track circuit applicable to Railtrack infrastructure. This characterisation will take the form of a permissible train current which can then be compared to the footprint of a piece of traction or rolling stock to enable a case to be made. Methods are included to analyse intact and faulty infrastructure.