scope:

This module describes the outline requirements and design methodology for the design of the removal of movement authorities after the occurrence of a SPAD; socalled

overrun management.

The principles in this module are to be applied for new and altered installations wherever reasonably practicable.

This module applies to signalling designers and representatives of the operations function.

NOTE: Representatives of the operations function may include the Operations Manager, Local Operations Manager and (Project) Operations Interface Specialist.

Purpose

This module forms part of the Signalling Principles Handbook (SPH:NR/L2/SIG/30009).

This module details Network Rail's policy on:

  a) the provision of signal passed at danger (SPAD) alarms;

  b) the detecting of overruns; and

  c) the controls to be applied to protect the overrun.

It provides SPAD risk mitigation supported by a reduction in complexity and cost of interlocking data while delivering similar or better operational safety.

This is a railway operations decision-making process.