Duplication of the Armadale suburban line was completed on Sunday, 3rd July 1904. Absolute Block working was introduced, with the Block stations being Cannington and Armadale. Temporary Block Stations were also established at Maddington and Kelmscott. Instructions published at the time advised: Up trains may be worked under "Section clear, but Station or Junction blocked" regulations Armadale to Cannington or Kelmscott when switched in. The instruments used were of the two-position block type designed by Winters, formerly of the Indian Railways.

In this photo, the interior of Armadale Cabin looks a little cluttered. Porters with Safeworking qualifications were appointed to work the panel, but towards the latter days of the cabin's life, even Special Class Signalmen were rostered from Perth to man the box on the Porter's RDO (rostered day off). A small panel it may look, but the morning and afternoon peak hours were certainly a trial! Note: That is not a transistor radio affixed to the block bell (sacriledge), but a custom made intercom to the relay room!

Armadale was also the junction of the single line section to Jandakot, which connected with Robb Jetty. Much evidence of this line can still be found. Beginning at Armadale, the foundations of the bridge across Neerigen Brook can be seen adjacent to the double track bridge. The curve, and then the long straight of Armadale Road parallels the railway formation for much of its length, including the old level crossing where Forrest Road joins from the left hand side at Forrestdale. From this point, the line changed sides, and culverts and small bridges can still be seen on the left just past the Nicholson Road junction at Forrestdale. The line's existence is somewhat obscure as it nears the Thompson's Lake area, due to roadworks associated with this new housing estate, and the Kwinana Freeway interchange. The line can be picked up again, running adjacent to Forrest Road in Jandakot, the station area now being populated by tall power pylons. Past here, it is still (just) possible to track the formation towards the Bibra Lake sidings as it passes near the popular Adverture World theme park. The line once serviced wool stores, industries and sidings in this area until joining up at Spearwood Jnc. with the Cockburn North to Robb Jetty line.

Armadale once had a yard with many roads, used for sorting wagons for the State Brick Works Siding. Later, a platform was built at this location to service the Armadale High School. The siding was then given the name Tredale. Signalling Plan 17491, produced in 1913, curiously shows Armadale's 32 lever frame reduced to 31 levers in a proposal to duplicate the line between Armadale and Wongong (later named Byford) for the "Naval Base stone traffic". In those days, Armadale also boasted a turntable. These days, little evidence of the turntable remains, except in a slight curve in the fall of the land near the recently provided Church Avenue level crossing.

Adjacent stations and cabins along the line over the years were - on the north side: Kelmscott; Gosnells; Maddington; Cannington; Welshpool; Carlisle; Rivervale (formerly Burswood) and Claisebrook. On the south side - was: Wongong (Byford) and Jarrahdale Jnc. (Mundijong Jnc.).

A relay interlocking installation was installed at Armadale on 9th September 1956, rendering the lever frame redundant, but permitting the much extended yard to be worked by searchlight type colour light signals and motorised points. The photo at left, is the south end of the yard, looking south towards Byford. The South West Main Line is the track immediately to the left of the concrete cable trunking. The loop is to the right, and the exit from the yard is on the far right. Note the robust cantilevered gantry carrying the loop signal, a left over from semaphore days. All the searchlight signals seen here are 'Departure Signals'. The shunt signals below, applied to the Tredale (school) siding.

Eventually, as with all other suburban signal cabins, the panel was made redundant with electrification of the line in the late 1980s. A careful observer can still however, find ample evidence of the location of each of the Home Signal bases.

The cabin can still be found today, but unfortunately not in its original location, or indeed in it's original context. It is now a tourist information office situated in a car park not far from the local council offices, but sadly not even on railway property. One positive note however, is that the signal panel is reported to have survived and is currently in storage. This may yet be returned to the cabin, and therefore (hopefully) be displayed in in its proper context.