scope:

This specification applies to those involved in the design of interlocking systems for use on the LU safety signalling systems need to use this specification.

This specification should be used when designing interlocking systems for use on the London Undergound safety signalling systems.

Note This specification does not cover certain processor based interlockings that have integrated control and interlocking (e.g. SelTrac S40), but these system should comply with the spirit of the requirements. It is expected that the processor based interlocking will comply with the principles contained within this document.

In addition this specification does not cover specific application design or configuration issues, which shall be described in the Systems Requirement Specification or other associated project documents.

Purpose

This specification defines the requirements for signalling interlocking systems used by London Underground (LU).

Note For the purpose of this specification, the interlocking system means the interconnected vital and non-vital sub-systems which provide the following functions:

a) interpretation of inputs from, and provision of outputs to, trackside equipment;

b) acceptance of commands from, and delivery of indications to, the various Control Systems and panels to which it is attached.