scope:

This SIGWEN applies to the manufacture, repair and servicing of electromechanical relays that form part of the infrastructure based railway signalling control system which are used in safety critical or safety related applications. Additional information will be added as necessary following identification and risk assessment of any new problems.

For service agents undertaking repair and servicing the proposed actions are stated.

For manufacturers, the information contained in this SIGWEN needs to be considered and any change made as a result will need to be product approved in accordance with NR/L2/ACC/029.

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

Purpose

This SIGWEN has been prepared to advise manufacturers, repair and service agents about problems affecting railway signalling relays used on Network Rail's Signalling Infrastructure.

The methods and processes used to satisfy the requirements of this SIGWEN should be detailed within the manufacturers' and/or service agents' documented procedures, as applicable.