In 1897 the Jarrah Wood and Saw Mills Company leased the W.A.

Timber Company's Ballaarat tramway route south of the Bunbury–Busselton railway was reused by the Jarrah Wood and Saw Mills Company for the construction of a railway between Wonnerup and Jarrahwood[1] in 1898–99.

[6] Construction of this extension was authorised through the Wonnerup-Nannup Railway Act 1907, assented to on 20 December 1907.

[7] As operated by the WAGR, the line was 38 miles 64 chains (38.80 miles, 62.44 km) from Wonnerup to Nannup and saw three trains per week in each direction during the 1940s.

[9] A re-commissioning study was conducted in 1989[10] but did not result in the reinstatement of the railway.