Australian railway signalling

rdf:langString Australian railway signalling

rdf:langString Australian railway signalling varies between the states of Australia, because each railway system was established under the different colonial governments with separate legislation. Just as with the notorious variation of Australian rail gauges, there are differing signal systems. The systems in New South Wales generally follow British precedents, although American influence has increased somewhat since the 1990s. Victoria uses American-style speed signalling on its main lines. That can cause confusion where the systems meet. For example, in New South Wales a green-over-red coloured light signal means "caution", indicating the next signal is at "stop". In Victoria, that same aspect means "clear normal speed", indicating the next signal is anything but at "stop". On the Main South Line from Sydney, single-light signals are now exclusively used from Spring Creek bridge (south of Galong) to Albury on the Victorian border. That forms a buffer zone between the conflicting signal indications of each state. Gradually, the remaining upper quadrant signals (and double-light signals at Binalong) are being replaced by single-light signals. South Australia uses two primary forms of signalling. Nearly all signal boxes in South Australia have now been closed, and most rail traffic is coordinated through centralised traffic control (CTC) systems, either under the Australian Rail Track Corporation (ARTC) from Mile End or Adelaide Metro control from Adelaide. Where the two networks interface, such as at the Goodwood level crossing or at Torrens Junction, control is usually by the ARTC after release from Adelaide Metro. The Western Australian system is the simplest to understand, and the complexities of leading position lights and other odd attachments to signalling apparatus have been either eradicated or were never part of it. Switchlocks are used to enter sidings from mainline CTC territory, such as the CBH Group yard terminal on the standard gauge railway. The train controller must release the switchlock, thus interlocking the signals to stop, which is similar to the system in Queensland. Perth's urban passenger network is operated by the Public Transport Authority and the rules are almost identical to those of freightlines.