NR SSI8003-105 ISSUE 1 PDF

Introduction

Neither the "AHBC Typical Circuits" Issue 2.0 nor the "MSL Typical Circuits" Issue 1.0 include circuits for the situation where there are two signals on the approach to the Crossing. However, the two signal situation has occurred on many occasions in the past and the guidelines in this document reflect the data methods used for those Crossings.

Fortunately the data constructs specified in the documents for Level Crossings with one signal, e.g. SSI8003-102 and SSI8003-104, are modular in concept and consequently the data for the two signal situation is an extension of that required for a single signal on the approach to the Crossing.

The data will basically be the same as that for the one signal situation, with the majority of the changes being those relating to the change of Sector identifier.

The only extra data required is that for the Approach Sector and the Outer Signal, shown as C1 and S10 respectively in the layout in Section 1.1, the latter only if that signal is within regulation distance of the Crossing.

The changes to the "core data" for Crossings, described in Section 3 with reference to SSI8003-102, is equally applicable to AHB and MSL Crossings.

The changes to the "specific data" for Crossings is described in Section 4 with reference to SSI8003-104 for AHB Crossings. However for MSL Crossings the changes will be very similar but should be made to the data shown in SSI8003-106 Chapter C.