The maps below show the development of the South Australian railway network from 1860 to 2010. The colours of the lines represent the gauge. As demonstrated by the maps, the gauges of the railways were not uniform almost from the beginning and transport between certain locations has long required transfers between the gauges. South Australia has had 3 mainline gauges for more than a century and had 14 regional 'breaks-of-gauge' (where transfers between the gauges occurred), making it the epicentre of Australia's railway gauge muddle.
Versions of some of the maps appear in the paper Sheard, N., 2024, "The Regional Economic Impacts of the Railway Gauge Muddle in Australia", Regional Studies, 58(4), 860–875 and its appendix. As the title suggests, the paper analyses how the gauge situation has affected the development of the railway network and the economy of regional areas. The appendix to the paper includes a detailed history of the rail network in South Australia and the gauge issue.
A shapefile of the railway lines in South Australia by gauge, from 1856 (when the first line was built) to 2016, can be downloaded here.