As part of the concession to a syndicate from Ballarat, Victoria, it was agreed that a mill would be established at Jarrahdale, a port at Mangles Bay and a railway line to connect the two.

A rubber-tyre steam traction engine, the first used in the colony, hauled the Governor Weld overland to Jarrahdale but the locomotive proved too heavy for the line and caused damage to the rail.

In the 1890s, the Jarrahdale operation expanded considerably under manager Alex Munro and the third jetty was built at Rockingham to allow for a large export order of jarrah sleepers to South Africa.

[1] Fierce competition between the eight largest timber operators in the 1890s eventually resulted in the merger of the eight into Millars' Karri and Jarrah Co. in 1902.

The opening of the South Western Railway in 1893, connecting Perth to Bunbury, meant the two lines interconnected at Jarrahdale Junction, now Mundijong.

This allowed timber to be transported directly to Perth, which now became the main market for the Jarrahdale mill, while exports were now handled by the port at Bunbury and supplied by other operations.

The line to Rockingham did however remain in use for firewood supplies, allowing Millars to retain the rights to operate the railway.