scope:

This standard applies to conventional, fixed block, wayside signalling. 

This standard does not apply to continuous automatic train protection, automatic train control system, non vital control systems and to depots.

For areas in which multiple aspect signalling is employed to facilitate the operation of other Train Operators, special consideration may be required which shall be agreed with LU.

Purpose

 The purpose of this Standard is to set out the London Underground (LU) functional and performance requirements for the safe system design, application design, installation and maintenance of conventional, fixed block and wayside signalling.