NR RT/E/C/19009 ISSUE 1 PDF

This document shall apply to all TI.21 track circuit testing and commissioning procedures, which incorporate interference tests.

It does not address the general personnel and system safety measures necessary for working on the track with signalling equipment.

PURPOSE

During the commissioning of TI.21 track circuits on the Mersey Rail re-signalling scheme, a number of track circuits were believed to have high residual voltages. An investigation (Technical Investigation Report 95501) into these allegations concluded that an incorrect test had been carried out.

TI.21 track circuits are widely used on the railway infrastructure, however, documentation relating to the testing of these track circuits is currently either unreliable or uncontrolled. The most commonly used reference documents include:

• BRB Code of Practice: 206-200-12

• ML Engineering: TD 6/5/21-1

• Southern Region Track Circuit Manual: Section TM 73.

The interference testing undertaken on the Mersey Rail scheme was carried out in accordance with Section TM 73 of the Southern Region Track Circuit Manual. However, the information relating to interference testing contained therein has been found to be incorrect.

The correct procedure for TI.21 track circuit interference testing is detailed in section GK/RC 0761 of the Track Circuit Handbook (GK/RH 0751). However, as this is not yet available, this document has been produced as an interim measure.