scope:

The scope of this paper is to gain approval by SSISPG of the SSI data solutions within this document, not with the principles involved as that forms part of the contract scope.

One of these principles seems to be that once the points have been called one way, they can not be called the other way until either the first part to move has become detected, or after 10 seconds. The Signaller should be made aware of this.

Purpose of Paper

This document details the requirements for the sequential calling of Point Ends to replicate the existing protection at a double junction with a switch diamond.

British Rail Research Report STG-D-PDS(SSS)-RP-17 into an incident with a single slip with switch diamonds at Watford Junction Points 3011, 3012 and 3013, and SSISPG response, 06-12-95, have been taken into account and recommendations implemented within the data constructs.

SSI8003-71 'Divided Sets of Points' covers data preparation for points which are divided for various reasons, split across TFMs and also split for detection. While Euxton is an interfaced SSI, this data is based on that in SSI8003-71, and it is anticipated that this may lead to an additional section therein.