NR NB 125 ISSUE 5 PDF

The suite of supporting notice boards applies to all projects amending or creating all types of data driven and circuitry systems.

This series of notice boards form the starting point of the re-development of generic design rules (principles) for interlocking logic. It is expected that further detail will be captured within the Signalling Principles Handbook, Typical Circuits and the SSI Application Guide.

‘Simple is Effective’ is part of the wider Network Rail Safe by Design initiative

Purpose

The notice boards listed below advise signalling system designers and engineers of innovations in interlocking requirements which aim to reduce design complexity while maintaining (and often increasing) safety. These innovations are intended to also reduce data volumes, equipment populations, circuit densities and offer a consequent reduction in the risk of errors arising during the life cycle of the signalling system. They can be applied to solid state signalling systems and route relay technologies and give the following benefits:

• simpler design approaches;

• more effective check and test;

• improved availability of the signalling system;

• reduced likelihood of promulgated error;

• reduced secondary operational risk