199304 – Norris – Integrating an Axle Counting Function into the VPI Computer Based Interlocking

This paper focus on the reasons why, some of the development processes used, and system description for integrating an Axle Counting function into the Vital Processor Interlocking, VPI, system.

During 1990 meetings were held between AB6 Signal (formally E6 Signal) and the General Railway Signal company, GRS, to discuss forthcoming tenders in Australia. It was during these talks that the idea of providing an alternative method of train detection for the VPI was discussed. This alternative system was to be axle counters.

In late 1990 Queensland Railways released a tender for the signalling of Farleigh to Purono. This section of railway included track sections which required detecting trains by using axle counters. This then became the opportunity to put the idea into practice.