This interlocking machine is one of the first in NSW and is typical of the multi-levered mechanical devices used in NSW railway signal boxes and on station platforms from the 1880s. It comprises a collection of levers for operating railway points and signals brought together in one machine. It was designed so that it prevented conflicting signal functions being set up simultaneously which might cause an accident. Before this, points were worked independently of each other, often by pointsmen in cabins stationed along the line.
This machine was manufactured in England by McKenzie & Holland and exhibited at the Sydney International Exhibition from 1879 to 1880. At the time, Britain led the world in the design and manufacture of safe railway working apparatus. The patent for the first interlocking machine was taken out in England by John Saxby in 1856 and by the 1870s thousands were in use in Britain but not in NSW. It was both the display of this McKenzie & Holland machine in Sydney, together with the 1878 train collision at Emu Plains west of Sydney the year before, that prompted the NSW railway commissioners to introduce interlocking machines on NSW railways in 1881.
This interlocking machine is significant because it was the forerunner of all interlocking machines used in NSW.
Information provided by Bob Taaffe
Curator, Science & Industry