scope:

This guidance applies to interlocking machines used by London Underground (LU) that ensure signals cannot be cleared unless points are in correct lie and also prevents the clearing of other signals such as might lead to the collision of two trains. Those engaged in devising maintenance regimes for hand and air operated miniature lever frames should follow this guidance.

Purpose

The purpose of this document is to provide guidance on the minimum annual maintenance requirements for hand and air operated miniature lever frames.

Note: This guidance is not intended to define the methods of test, but where it does so the Maintainer should adhere to those tests.