NR NR/L2/SIG/19820/K01 ISSUE 1 PDF

This specification provides guidance to lead engineers who are specifyingenvironmental requirements during the development or approval of signalling equipment.

NOTE: It is assumed that the lead engineer using this specification to prepare environmental requirements is familiar with the product. Assumed knowledge about the product includes installation location, size, operating principles and failure modes of concern.

It applies to signalling equipment permanently placed at a defined site, portable equipment required for testing or maintenance of signalling equipment and equipment during transportation and storage.

It covers vibration caused by rail traffic but not vibrations caused by track maintenance trains.

It is not suitable for use for train borne equipment and does not cover equipment which is installed but not operational.

The effect of climate change is not in scope of this specification. The values given in this specification can be revised and justified using the climate change projections in NR/GN/ESD23 Guidance Note – Weather resilience and climate change adaption.

NOTE: NR/GN/ESD23 can be found at https://safety.networkrail.co.uk/home-2/environment-andsustainable- development/wrcca/

As significant changes in the climate are projected over the next 30 years and beyond the potential impacts on signalling assets should be considered if the product has a long service life, for example over 20 years.

Lightning, EMC, fire protection and power supplies have not been included as part of this guidance. Electrical requirements do not normally form part of an environmental specification. This is a separate standard for EMC, BS EN 50121-4, which includes lightning which should be specified by the lead engineer as a separate requirement.

Purpose

This specification supports compliance to BS EN 50125-3.

NOTE: In some instances, the environmental parameters given in that document have been revised. This is either due to the parameter in BS EN 50125-3 being ambiguous or because experience has shown that the parameter given is not representative of our operating environment. Cases where the values given in this document do not match those given in BS EN 50125-3 are highlighted and justified as appropriate.

It allows the lead engineer to:

a) identify the environment in which the signalling equipment is expected to function;

b) write a test specification tailored to the product which demonstrates the equipment will function in the defined environment;

c) understand the failure mechanisms associated with different environmental parameters.