scope:

Introduction

Railtrack Line Specification RT/E/S/10131 Issue 1 specifies two separate functions:

• Emergency Signals On Control (ESOC), which affects all signals within an interlocking, and is independent of the CI and Control Centre hardware, programs and data.

• Signal Group Replacement Control (SGRC), which provides an operational function affecting a group of signals. This relies on the correct operation of the CI and Control System.

ESOC is only intended for use when technical failure may render the normal means of signal replacement inoperable. Details for implementing ESOC are contained in SSI8500, primarily in Chapter F.

Details for implementing SGRC follow below.