NR NB 204/APP2 ISSUE 1 PDF

See NB204/lndex. This appendix should be applied when:

•    new control systems are to be provided;

•    alterations are to be made to existing control systems;

•    existing control systems are to be renewed or re-platformed.

NOTE: Alterations to existing installations should follow this appendix where reasonably practicable, unless doing so would create a significant risk of signaller error, in which case the existing practice in that location should be retained.

Reason for issue

To minimise the potential for recent changes to signaling standards to mislead the signaller due to inconsistent or inadequate information being provided.  With larger control areas the likelihood of this occurring increases, especially if the signaller is under pressure when dealing with unusual or degraded situations.

This notice board is being issued in advance of a planned change to standards to update a series of symbols used on signal box diagrams, panels and VSCS workstation maps as described below.