scope:

General

These requirements are primarily intended to be applied to new VDU based signalling control systems. Retrospective application of these requirements shall be considered where supported by a risk assessment for the signalling system.

The use of SPAD alarms at other types of signalling control centre e.g. Panel or Lever Frame, may be required in which case the principles for SPAD detection outlined in Appendix A and the general handling of alarms shall apply.

Purpose

This specification defines the operational and technical requirements for the provision of SPAD alarms at signalling control centres. The objective is to present a consistent approach that reflects best practice and to ensure that human factors considerations are properly addressed.