scope:

INTRODUCTION

This module applies, in support of GK/RT0060, to the design of interlockings (including ground frames) associated with:

a) mechanical signalling systems;

b) electro-mechanical signalling systems;

c) electro-pneumatic signalling systems;

d) all-electric non-route setting signalling systems;

e) free-wired route setting signalling systems;

f) geographical route setting signalling systems;

g) electronic signalling systems; and

h) hybrid systems.

Where appropriate, reference to "signals" should be understood in relation to movement authorities within both lineside signalling and cab signalling systems.

This module does not cover the presentation and production processes for design details.

For the presentation and use of mechanical locking charts, interlocking circuit diagrams and central interlocking data listings within the design process, see NR/L2/SIG/11201, Module A2. and NR/L2/SIG/11201, Module A19. Documentary requirements for control tables are given in NR/L2/SIG/11201, Module A18.

Where it entirely addresses the situation under consideration, the use of this Standard is an alternative to the risk-based approach. However, where the particular application or intended environment for the system introduces additional risks, these should be subject to separate assessment.

The design principles in Section 2 give the minimum requirements, even when the risk-based approach is used. These principles are mandated in NR/L2/SIG/11201. More detailed requirements for the design of interlockings are given in Section 3. Sections 4 to 8 describe the application of the design principles and requirements, as evolved through different interlocking systems, starting with the most basic.

The following guidelines should satisfy the principles encompassed within the Standard:

a) guidelines on mechanical locking in NR/L2/SIG/11201, Module B8;

b) guidelines on relay route setting applications in NR/L2/SIG/11201, Module B9;

c) the route relay interlocking typical circuits listed in NR/L3/SIG/19272;

d) guidelines on geographical relay interlocking systems in NR/L2/SIG/11201, Module B10;

e) guidelines on electronic interlocking systems in NR/L2/SIG/11201, Module B11; and

f) interlocking systems application manuals, such as NR/L2/SIG/17002 for SSI.

The use of interlocking circuits or system application manuals that pre-date this standard should be assessed against the design principles given in Section 2 and the signalling principles in NR/L2/SIG/30009.

The examples shown in this Standard are based on the signalling layout and control table illustrations given in NR/L2/SIG/11201, Module A18.