scope:

This Railtrack Line Code of Practice applies to all Westinghouse M3 point machines installed on Railtrack's infrastructure.

This document does not address the general personnel and system safety measures necessary for working on the track with signalling equipment.

Purpose

During 1995, an inspection of Westinghouse M3 point machines in accordance with SIN 052 revealed a number of problems, one of which being excessive longitudinal movement of the circuit controller main shaft in its bearing. In addition, it was also reported that the bearings in which the main shaft rotated, were a version that was not locked. It is known that problems appertaining to loose circuit controller bearings have, in the past, led to a derailment.

This document has been prepared to explain the implications of a circuit controller main shaft having excessive longitudinal movement, and to provide advice on:

• checking circuit controller main shaft bearings

• temporary measures required to lock the circuit controller main shaft bearing until the machine can be replaced.