THE SIGNAL BOX
Photograph by Dr J W F Scrimgeour
These intriguing double-line block instruments were designed by a signal engineer from one of the Indian Colonial Railway companies.
In early days a variation of this type of instrument was also used on single lines (without train staffs!) and this system can be seen illustrated at Newmarket Junction in New Zealand in 1904. This type, known as the English Pattern, was readily identified by the switch on the left hand side. They were also used as such in Western Australia, and maybe elsewhere. Conversion for use as single line instruments was a simple as the removal of one single wire inside the instrument.
The first installations in Australia were probably in Victoria, followed by South Australia (around 1888, for single lines), Western Australia (from mid- to late- 1890s, possibly initially using instruments from Victoria) and then New Zealand. All were initially of the "English" pattern.
The switch on the front (in lieu of the side) came later and was referred to as the Newport Pattern indicating they were built at Newport Works in Melbourne from around 1900. South Australia certainly made some of their own instruments.
Those illustrated here were in use on the Western Australian Government Railways and were of the Newport pattern, also sometimes referred to as WA Standard Block. But similar examples could be found on other railways in Australia - see Royal Park for examples on the Victorian Railways.
The examples shown here were in Gosnells cabin, a simple double line station with just a crossover and loop siding. It was between Maddington and Kelmscott, and was a suburban station on the Perth - Armadale line.
The normal position of the needles is at CLEARED, and the normal
position of the switch is OFF. The sequence of operation for the passage of a
train is as follows:
It is interesting to note that the operation of the indications was initiated by the signalman at the "rear" end of the section, a complete reveral of British practice whereby the accepting signalman had full control of the indications.
For many years I had thought this type of instrument was extinct but in 2015 I learnt that they are still in use at Craigieburn, Kilmore East, Broadford and Seymour. The first-mentioned is actually in a computer-based signalling centre!
Additional notes by Chris French, Chris Jaworski and Bob Taafe
Comments about this article should be addressed to John Hinson