Australian railway signalling
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.
From the early 1870s, several near-misses and minor derailments led to serious discussion of improved safe-working arrangements and the implementation of interlocking.
Despite this, very little action was taken until 1877, when a new rule book including the Staff & Ticket and Block Telegraph systems was finally printed.
This installation was electro-pneumatic and controlled from a miniature lever frame supplied by the McKenzie, Holland & Westinghouse Power Signal Co. of Worcester, England.
[3][page needed] Signalboxes remain scattered throughout the Sydney Trains network, with thirty-six still in regular use in 2012, including nine controlled by local station staff, twenty-six by dedicated Signallers and one shared by both.
Junee and Broadmeadow are home to integrated electronic control centres, both of which are run by the Australian Rail Track Corporation, custodian of the busiest lines in the country network of the state.
Standard British three position lower quadrant semaphore signals, with an arm for each direction and spectacles mounted below them, were used from the introduction of time-interval working in 1855.
The yellow light was originally said to mean 'attention - proceed at medium speed' in accordance with a 1924 study by the Institute of Railway Signal Engineers in which Byles participated.
In the Underground City and Eastern Suburbs railway lines, a speed restriction of 30 mph also applies to the Caution indication.
Speed control by intermediate train stops, based on Byles' system, was introduced on the London Underground following the accident at Moorgate on 28 February 1975, in which 43 people were killed.
Varying numbers of intermediate train stops are spread out between signals, most notably at underground platforms on the City Circle and Eastern Suburbs Railway, but also at some above ground locations.
At some locations, the Low Speed indication will only be exhibited under reduced overlap conditions (e.g. owing to the presence of a train ahead).
This appears similar to the Low Speed indication, except that the subsidiary green light is provided in a separate lamp case below a plate labelled "CLOSE UP".
[2] It is often used before a Medium indication to provide additional notice of the need to reduce speed for a facing junction, the equivalent of the British flashing double yellow.
This system is derived directly from British multiple-aspect signalling, with American influence in the form of a marker light.
The caution turnout indication was a single yellow in the main head over three white lights at an angle of 45 degrees.
In order to provide warning of upcoming turnouts, QLD makes use of Dynamic Speed Indicators, these are boxes below the main set of lights which contain yellow text.
Where these two networks interface, such as at the former Goodwood level crossing or at Torrens Junction (both now grade separated), control is usually from ARTC after release from Adelaide Metro.
Despite the almost uniform CTC control some signal boxes still exist, such as Dry Creek South although they are not normally switched in.
A reduce to medium speed aspect is also used to give early warning of a divergence, and is given by a flashing yellow light.
Despite this re-signalling, some parts of the TransAdelaide network still use the original 3-position speed signalling (such as the Dry Creek to Port Adelaide line).
The consequence of this is that it theoretically possible to confuse two and three position signals; this risk is managed by limiting what aspects are allowed at a particular site.
Heavier suburban traffic on the Melbourne network saw a greater strain on the block working then used, which required a large number of staffed signalboxes to enable trains to run close together.
In the 1960s the Commonwealth and Western Australian Government decide to build a standard gauge railway from Kalgoorlie to Perth.
Staff and Ticket were the primary form of signalling safe working system used in Western Australia apart from major yards and main lines such as the Eastern Goldfields Railway.
Absolute block is used all throughout Western Australia with exception to the Pilbara Railways as no information has been attained to cover that area.
The Western Australian system is very simple to understand but the complexities of leading position lights and other odd attachments to signalling apparatus have been either eradicated or were never part of it.
[26] Perth's urban passenger network is operated by the Public Transport Authority and the Rules are identical to that of the freight, with a few minor differences.
