scope:

This Code of Practice applies to GEC Reed equipment used to remotely control signalling functions, e.g. points and signals and indicators.

The following topics are dealt with in this Code of Practice:

• the signs and symptoms of multiple channel signal oscillation (generally referred to as the "woodpecker effect");

• preventative and corrective measures that can be taken to reduce the risk of woodpecker effect occurring;

• the signs and symptoms of self-oscillation on receiver amplifiers;

• corrective action that should taken if self oscillation of a receiver amplifier is suspected;

• degraded power supply capacitors on Type R systems. The possible symptoms exhibited and what corrective action should taken;

• effective cable jointing techniques for jointing Reed FDM cables, used on control and indication circuits, particularly solid core 1/0.85mm conductors intended to avoid the need for slip-links.

This Code of Practice does not provide any guidance in relation to the general personnel or system safety measures necessary for working on the track with signalling equipment.

Purpose

The aim of this Code of Practice is to describe the nature of certain in-service problems that have arisen with GEC Reed equipment, the symptoms manifested, show how they can be avoided and where possible, what remedial action can be taken if these problems are experienced.

This document also describes best practice for jointing the transmission line cable used on Reed systems.