scope:

This document covers interference with telecoms systems only and does not include:-

• analysis of interference to signalling, electrification and other equipment which may result from connections carried through lineside telecoms systems;

• retail telecoms systems;

• third party systems (either side of the railway boundary);

• train borne systems.

Other generic types of lineside system not covered by this document, may be included within the scope of NR/GN/SIG/50014 (Ref. 2.2.6) or in the specific IDI document for the equipment. Compatibility with telecoms systems outside the railway is addressed in NR/GN/SIG/50018

This document does not attempt to present a method of devising susceptibility levels of all equipment utilising lineside telecoms cables and transmission systems to an individual train limit. See clause 1.4 regarding further work being done to determine if it would be possible to derive such a limit.

Where relevant, the methodology considers failure modes of both rolling stock and infrastructure.

The methodology here assumes that the railway electrification is installed as per current Network Rail practice (i.e. booster, earth wire or rail return 25kV AC systems and 'classic' or 'high power' third rail, 750V DC systems). Different electrification configurations, such as use of resonance dampers or 25-0-25kV autotransformer systems, are not specifically covered by this document and require a separate analysis and/or a reissue of this document.

Where the term 'train' is used, this is defined as the maximum number of vehicles which is permitted to operate as a coupled set.

Purpose

The purpose of this document is to provide a methodology to demonstrate electro-magnetic compatibility with operational telecommunications equipment and systems on the AC and DC electrified railway on Network Rail Controlled Infrastructure. This is achieved by:

• Identification of the generic types of operational telecommunications equipment and systems present on the AC and DC electrified railway on Network Rail Controlled Infrastructure.

• Identification of safety related hazards caused by EMI from electric rolling stock and from currents drawn from or transmitted into the electric traction supply system.

• Identification of applicable standard limits and other criteria.

Combining these elements will enable the relevant permissible EMI levels to be determined. This characterisation can then be compared to the emission signature of an item of rolling stock obtained through testing. This methodology will facilitate the demonstration of compatibility of rolling stock with operational telecommunications equipment and systems, as part of a Route Acceptance Safety Case.