REGISTER

Wayne McDonald BE (Elec), FIRSE

Siemens Rail Automation

Australian Railway signalling has relied on tried and proven track circuits of all technologies for train vacancy detection. Signal Engineers and maintainers assimilated the resolution of the traps and pitfalls through procedures, the school of hard knocks, and mentoring from the industry die-hards. The corporate experience and knowledge has resulted in continued issues being addressed or accepted to the extent that they are invisible..

Enter axle counters. They are not, as some have suggested, the panacea for all train detection ills. While they are immune to ballast conductance, the vagaries of wheel-rail impedance and while they eliminate bonding restrictions they also introduce a whole new set of problems for the uninitiated (gotchas) that require new understanding, new techniques and the application of investigatory skills to resolve.

This paper broad brushes the issues and utilises two case studies, on two different axle counters, to introduce causes of under and over counts and demonstrate a scientific approach to addressing the problems when axles just don’t count properly.