When Colac station opened, it was the terminus of the line from Birregurra. On 2 July 1883, the extended line to Camperdown was opened.[1][2]
Goods facilities included a brick goods shed, and a steel portal framed shelter was added when the Freightgate centre during the 1980s. During 1988, a number of sidings were removed, including the oil siding at the up end, and No. 6 road.[3] In 2008, the points for the crossing loop were removed.[2]
In December 2010, a siding was provided for the stabling of track maintenance machines.[4]
Colac was the interchange with the 2 ft 6 in (762 mm) gauge Crowes line, which was opened in the early 1900s to serve the farming and timber-harvesting areas in the Otway Ranges. The line was built in two stages, with the first to Beech Forest opening on 1 March 1902, and the second to Crowes, on 20 June 1911. The line was closed in sections: Ferguson to Crowes on 9 December 1954, followed by a reopening to Weeaproinah on 19 January 1955, and full closure on 30 June 1962.[5]