scope:

This Standard applies to all types of signalling works carried out in legacy signal boxes which contain a lever frame or other local control method e.g. where the signaller interfaces include a control desk and / or block shelf / block bench with indicators and layout diagrams.

This Standard covers both hardware and modular units particular to legacy signalling. It identifies the modern equivalents for equipment such that it becomes more likely that these legacy sites can be kept serviceable for their planned life at unit costs which are affordable. By the adoption of these products they become more consistently applied and understood by local technical staff.

Reference to particular items of equipment in this module usually confers product acceptance or type approval.

Purpose and Introduction

This module forms part of the Signalling Design handbook (SDH: NR/L2/SIG/11201) and is to be read in conjunction with the other modules of the handbook and reference documentation.

This Network Rail standard contains requirements and guidance on signalling engineering applications. The content supports the specific and general requirements described in Railway Group Standards and the Network Rail Signalling Principles Handbook [NR/L2/SIG/30009].

NOTE Where there is a conflict between this standard and a Railway Group Standard or the Network Rail Signalling Principles Handbook [NR/L2/SIG/30009] then this standard does not take precedence.

Decisions made by a competent person should be supported by appropriate evidence or documentation.

NOTE Use of designer notes on drawings (see HSE CDM guidance) will generally suffice as may Design Log entries.

Any adoption of alternative solutions requires an assessment commensurate with the significance of the proposed change and which follows the guidance provided by the Common Safety Method for Risk Evaluation and Assessment [CSM-RA]; Network Rail's adopted method for the control of safety risks.