scope:

Magnetic induction affects all conductors that run in parallel with electric traction systems.

This guidance note covers traction coupling to lineside cables in general, but only covers the immunisation of telecommunications systems. Signalling has a suite of standards (NR/L2/SIG/50xxx) which cover the immunisation of specific systems, so the effects of electric traction on signalling are not covered.

This document updates much of the technical information provided in BR 13422, although it does not reproduce in detail the methodology for calculating induced longitudinal voltage, as this is now achieved with modelling.

Purpose

This guidance note provides an overview of the coupling between traction current and induced voltages on lineside cables and the effects this has on personal safety, and equipment malfunction.

It describes the influencing factors, potential risks and available mitigations to reduce the effects.

It is also a useful reference to mandatory standards which control the risks associated with traction-induced voltages on lineside cables.