scope:

This standard applies to the manufacture, repair and servicing of electro-mechanical 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 needs to be considered and any enhancements made to equipment to prevent the problems detailed in this document shall be subject to the appropriate approval regime prior to implementing any change to the equipment.

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

Purpose

This standard 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 standard should be detailed within the manufacturers and/or service agents documented procedures, as applicable.