"[3] The South Australian and Victorian governments agreed on 28 November 1912 to connect their respective railway networks at two places by constructing lines between Heywood and Mount Gambier and between Murrayville in Victoria and Pinnaroo in South Australia with legislation subsequently passed by both parliaments being enacted on 14 December 1912 and 23 December 1912 respectively.

[3] The railway line opened for business on 28 November 1917 without any "special ceremony" and with passenger services scheduled for Mondays, Wednesdays and Fridays.

[5][3] The South Australian section of the line between Mount Gambier and Rennick was used by the tourist service, the Limestone Coast Railway, until 20 March 1999.

[citation needed] In 2009, the South Australian and Victorian governments published an action plan for freight services within the Green Triangle Region which advised that projected volumes of woodchip intended for export from the Port of Portland in the years 2012–2015 would make a restored Mount Gambier–Heywood rail line a "potentially … commercially viable" operation.

[5] In 2020 the Limestone Coast Regional Development Board conducted a feasibility study with the CSIRO to build a Freight Department at the Glenburnie Saleyards to reopen the line to Heywood and connect with the Melbourne to Adelaide network but is still being pursued for government standardisation.