NR NR/L2/SIG/30009/E042 ISSUE 1 PDF

The contents of this module supports RSSB documents GK/RT0055 and GK/GN0655 and applies to all uni-directional lines where the trains are signalled in accordance with the Regulations for Train Signalling by the Absolute Block System (Absolute Block Regulations). (For bi-directional lines, see NR/L2/SIG/30009/E051).

This module applies to all new provision and, subject to consideration of "using reasonable opportunity" and practicability, all alterations to signalling where the changes appreciably alter the layout risk associated with any of the signals within the scheme. Where the content of application standards (such as NR/L2/SIG/11201, SSI8003, CAT0005) are different to the requirements described in this module, this module takes precedence.

Changes to layout risk are likely when any of the following apply:

a) alterations are made to a layout;

b) lines become designated as passenger;

c) layouts are re-signalled or relocked (or re-controlled, though it is recognised that the opportunity to mitigate existing risk is generally limited);

d) additional routes are provided;

e) a platform is added;

f) permissible or attainable speeds are changed, raised or lowered;

g) an overrun or timetable risk assessment (or similar) identifies the need to review protection.

It is not intended to be applied to minor signalling alterations where the scope of the scheme does not make any material impact to layout risk on any of the signals within the scheme.

Purpose 

The purpose of this module is to define the signalling requirements for the safe movement of trains on running lines where signallers are required to confirm that the train has cleared the block section and is complete. 

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. 

It details Network Rail’s requirements for the provision of block controls and 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. 

This module 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 1 for extract.