scope:

This document is intended for the information of users of installed SSI systems, and does not cover those elements of SSI used with the Design Workstation and On-Site Simulation systems, nor those activities relating to data preparers and scheme designers.

It also describes SSI emulators that are used to replace SSI central interlockings. 

Section 9 contains advance information on some current development activities and their impact, which are not yet included in SSI8150. A separate Appendix NR/GN/SIG/17901/A lists the Category of each Central Interlocking currently installed on Network Rail infrastructure.

Should there be any disagreement between this document and the SSI Applications Manual, the information in the SSI Applications Manual is to be taken as definitive.

Purpose 

This document is a guide to the permitted configurations of SSI Hardware and Software as in use by Network Rail, based mostly upon information contained in the SSI Applications Manual [NR/L2/SIG/17002] and the SSI Software Record [SSI8150]. 

This document provides guidance on the use of the following equipment: 

  Panel Processor Modules 

  Interlocking and Diagnostic Multiprocessor Modules 

  Memory Modules 

  Data Link Modules 

  Long Distance Terminals 

  Signal Modules 

  Points Modules 

It describes through reference the various Categories of SSI system, and the permitted combinations of hardware and software in each Category. This document identifies each Category and its defining features, together with upgrade paths and their advantages.