scope:

This document applies to those involved in the specification and design of and modifications to Signalling Control Systems need to use this document. This document shall be used when designing Signalling Control Systems and modifications to them.

Note This document covers the philosophy of automated control by computer systems, but does not consider manual based control systems such as the older signal boxes with levers or with push-buttons. It is not expected that modern TBTC / CBTC systems meet all of the requirements in this specification, but should meet with the spirit of them.

It is not the purpose of this document to describe in technology specific terms how the philosophy is to be met. Reference should be made to the signalling control systems codes of practice relating to computer systems and G2501 'Signalling Control systems (computer systems)' for this level of detail.

Purpose

This document is intended to provide the underlying philosophy that must be adopted when preparing and introducing signalling control systems to London Underground (LU).