scope:

This standard applies when making any planned change to the safety signalling system for which LU is the Infrastructure Controller where that change involves either:

a) a departure from the existing design; or

b) a change of component type or version.

This standard also applies to any interfaces (such as power supplies, arrestors or point heaters) whose alteration might directly affect the safe operation of the signalling.

The requirements of this standard generally do not apply to exact like-for-like substitution of components, but shall apply (in whole or in part) if extensive and simultaneous like-for-like replacement or reinstatement is planned, even where this does not depart from the existing design drawings.

The requirements of this standard are to be considered when planning the alteration of Signalling Control Systems.

This Standard is written in terms associated with hard-wired systems but is to be applied to data driven and other software based systems as appropriate.

This standard does not address the safety assurance or design approval process required for new types of equipment (refer to Standards S1197, Signalling and Signalling Control - Design and Implementation and S1201, Signalling and Signalling Control - Approvals), or the detailed planning and documentation of testing (refer to Standard S1198, Signalling and Signalling Control - Installation, Testing, Commissioning and Handover). However, the totality of requirements contained within the complete suite of Signalling and Signalling Control Standards, see 5.1.2, are to be complied with as appropriate for the planned change.

The Standard has been re formatted and re-numbered from 1-200 A2. There were no technical changes.

Purpose

The purpose of this Standard is to define the requirements applicable to the making of planned alterations to hardware or software during the life of a Signalling System.