NR NR/L2/SIG/11201/MOD B12 ISSUE 5 PDF

This module applies to the design of Transmission Systems (including Cables, Terminations and Cable Routes).

Transmission systems (including cables) are provided as a means of interconnecting systems, sub-systems or items of equipment. Additionally, cables (commonly, but not universally single core) are provided as part of the internal circuitry of individual items of equipment.

Cables fall into four broad areas of application:

a) internal wires within an installation or sub-system (predominantly single core);

NOTE Internal wiring of manufactured units is covered by the product approval process.

b) main cables providing external transmission between installations or subsystems including power distribution, direct-wired, remote control and datalink systems;

c) tail cables providing connection from lineside equipment housings to trackside or on-track equipment (sometimes via disconnection boxes), including track circuit connections and lineside operational telephone cables;

d) bonding cables (usually single core) provided for track circuit, earth and equipotential bonding.

Terminations are provided as a means of interfacing between differing types and/or sizes of cable and also in order to provide circuit disconnection and/or test facilities.

Cable routes are provided as a means of constraining cables and also protecting them from their environment.

The Design Principles in Section 2 give the minimum requirements, even when the risk-based approach is used. These principles are mandated in NR/L2/SIG/11201.

The Network Rail standards on the following subjects should satisfy the principles encompassed within this module:

a) details of approved railway signalling cable

b) details of approved railway signalling cable with preformed ends and plug coupled ends;

c) details of approved railway signalling cable for aerial use;

d) details of cables for railway telecommunications ;

e) details of cable for data links;

f) details of coaxial cables;

g) guidelines on the construction of cable routes; and

h) guidelines on the installation of cables in NR/L3/SIG/11303 (Appendices 2A10 & 2A15).

PURPOSE

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.

It 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.