REGISTER

Geoff Everist BE (Electrical) MIEAust AMIRSE

Union Switch & Signal Pty Ltd

To suggest that Australian railway operations suffer from the "tyranny of distance" is not only a cliché but an understatement. Australian freight railway lines are characteristically long and thin (pretzels), with critical infrastructure often in remote and isolated locations. From an economic standpoint, the negative impact of distance is compounded by the curse of low density.

From a railway communications perspective, this isolation combined with a critical operational dependence on the availability of communications infrastructure has historically led to in-house provision of this infrastructure. Competitive pressures combined with advances in technology have driven modern railways towards centralisation of control of their signalling systems. Telemetry data communications are an often neglected but critical component of any centralised and therefore remote controlled signalling system. The data communications backbone is generally common to all elements in the overall scheme; therefore the entire system is dependent upon its reliable operation. Traditionally, telemetry data communications have been provided over bearers provided primarily for voice communication.

Australian Rail Track Corporation (ARTC) have recognised that in-house provision of communications infrastructure is not sustainable and are implementing strategies to also use existing service provider networks. Utilisation of existing commercial service provider networks (puddles) solves many problems, but introduces new problems that require careful consideration and management. The telemetry system upgrade for the NSW North Coast CTC provides a useful illumination of some of the issues involved and their innovative solutions.