scope:

This module primarily reflects multiple aspect signalling to which Track Circuit Block Regulations apply, controlled from a route setting panel or VDU system. The concepts also apply to other interlocking and block systems. Any significantly different / additional considerations to other forms of signalling are specifically identified.

This module and those directly associated with it equally apply to railway which is ETCS fitted unless there are no applicable lineside signals. 

NOTE: The principles appropriate to Modular Signalling are as specified within the functional requirements of NR/L2/SIG/30097/Appx C which references those standards extant in April 2014 and therefore is not affected by the publication of this module. 

This module applies to all signalling schemes and detailed design where:

• colour light signals are altered, re-locked or re-controlled; 

• new signals are introduced; 

• control systems are altered, renewed or re-platformed; 

• new control systems are introduced. 

All alterations are subject to consideration of "using reasonable opportunity" and practicability. 

This module defines the requirements for the provision of controls to allow the signaller, other operator, or automated systems to: 

a) request issue of an appropriate movement authority from a signal (to display aproceed aspect); 

b) request withdrawal of a movement authority from a signal (to display a stop aspect). 

NOTE: The requirements and guidance for group replacement functions are also included in this document.

Purpose

This module forms part of the Signalling Principles Handbook (NR/L2/SIG/30009) and is to be read in conjunction with the other modules of the handbook. 

The SPH details Network Rail's requirements for the provision of interlocking between signals, movable infrastructure such as points and other parts of the signalling system to control the risk of: 

a) failure of moving infrastructure to establish a wheeled path; 

b) collision between a train and another train legitimately present; 

 c) the issuing of a movement authority to the train driver and its subsequent removal. 

The SPH comprises mandatory sections and guidance. The guidance is to be followed unless an alternative can be demonstrated to be beneficial and no less safe. It satisfies the relevant parts of the IRSE Fundamental Requirements for Train Control Systems, see Appendix D for extract.