[4] The first, East Perth to Pinjarra, was undertaken by William Atkins (former mill manager of the Neil McNeil company at the Jarrahdale Timber Station)[5] and Robert Oswald Law (who built the Fremantle Long Jetty) from the end of 1891.

[7][8] The second phase of construction was also completed by Atkins and McNeil, starting at Bunbury and working north to Pinjarra opening on 22 August 1893.

During World War II, plans for its full duplication between Armadale and |Brunswick Junction were therefore included in an intended post-war improvement project.

The CTC was then extended progressively southwards, to North Dandalup by April 1959, and then to Pinjarra, including a crossing loop at Venn, by June 1959.

[10]: 38 Proposals for a 7.9 kilometres (4.9 mi) extension of the double tracked Perth suburban portion of the line from Armadale as far as Byford, and installation of the CTC all the way to Brunswick Junction, both ended up being abandoned due to a shortage of funds.

[15] The section controlled by Arc Infrastructure has been upgraded to accommodate 21-tonne (46-thousand-pound) axle loads, featuring concrete sleepers and continuous welded 50 kilograms per metre (100 lb/yd) rail.

[22] The Transperth commuter rail Armadale Line operates a frequent passenger service at the Perth end of the route.

It traverses the entire length of the line from Perth to Bunbury twice a day in each direction, taking about 2 hours and 30 minutes each way.

[26] Freight services on the line are operated by Aurizon and are primarily focused on bauxite and alumina mining and refining.

[27] Caustic soda is transported from Bunbury Port to Wagerup and Worsley for use in alumina refining and some coal from the Collie branch is also carried on the line.