The railway line was constructed in stages, and not as one continuous project. Katanning had been connected to the Great Southern Railway by 1889 but
Kojonup had been bypassed by the line and argued for a rail connection to the network. The Katanning to Kojonup section was surveyed in late 1905, construction commenced the following year and was completed in March 1907. The Katanning-Kojonup line was officially opened on 10 April 1907 but, at this point, only the railway line existed and no buildings or platforms. With the arrival of the railway at Kojonup, towns further west lobbied for extending the line to
Boyup Brook and on to Donnybrook to connect to the
South Western Railway via the
Northcliffe railway line. The Donnybrook to Noggerup section opened to traffic on 26 March 1908, followed by the Noggerupp to Boyup Brook section, which opened on 10 March 1909. The final link, the Boyup Brook to Kojonup section, opened to traffic on 21 May 1912. Construction of the line was put out to public tender but the Western Australian
Public Works Department was found to be the cheapest bidder and was tasked with the building of the various sections of the line with the exception of the Boyup Brook to Kojonup link, which was carried out by a private company. In 1926, through the '''', a
railway connection from the Donnybrook–Katanning railway to the Great Southern Railway was approved, from
Boyup Brook to
Cranbrook. Construction of this line was started but never completed. Regular passenger services on the railway line continued until the late 1960s, when road transport overtook the railway in popularity, but special passenger services operated on the line until 1974. Freight services continued until the early 1980s, but the line was seasonally closed in 1981. In early 1982, extensive flooding damaged the line around Muradup and the decision was made to close the railway line, which took effect on 1 June 1982.
Boyup Brook and
Kojonup were significant locations on the railway. The section of the railway between Donnybrook and Boyup Brook is now held under a 49-year lease by
Arc Infrastructure, having been included in the privatisation of
Westrail freight in 2000. The section from Boyup Brook to Katanning remains under the control of the
Public Transport Authority. ==Acts of Parliament==