scope:

This document applies to electromechanical relays and searchlight signal mechanisms, that form part of the infrastructure based railway signalling control system, and which are used in safety critical or safety related applications.

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

Purpose

This document has been prepared to summarise problems affecting railway signalling relays and searchlight signalling mechanisms used on Railtrack's Signalling Infrastructure. It includes the measures necessary to control the risks presented by these failures.

It is anticipated that this document will develop to become a controlled repository for providing advice and information on signalling relay and searchlight signal mechanism problems and eventually incorporate those problems contained in GK/RT0129. However, in the mean time, as this document cannot be regarded as comprehensive, reference should also be made to GK/RT0129.