Railways in Australia

"The New South Wales government - at that time New South Wales still included Port Phillip - agreed in 1848 to accept the Stephenson gauge, but two years later the Sydney Railway Company asked the Colonial Office if the Irish standard might be adopted instead. The Colonial Office offered no objection, and the Australian plan - this time with the approval of Victoria and South Australia, by then separated - was approved. But Sydney then unilaterally decided to revert to the 4 foot 8.5 inch gauge, and began construction of its system. Since the other two colonies had already ordered engines and rolling stock on the previous basis, furious dissension was expressed. London did its best to persuade New South Wales to stick to its agreement, but could hardly interfere in the domestic concerns of independent colonies; New South Wales therefore went one way, South Australia and Victoria another.
The Issue became more complex when in 1870 South Australia decided to construct feeder lines, some of considerable length, connecting the 5 foot 3 inch main line to a narrower gauge, of 3 foot 6 inches. Goods or people moving between Sydney and the South Australian back country would therefore have to transfer twice, adding considerably to the costs and time taken for the journey. When Queensland, prompted by Robert Herbert, pressed ahead in 1864 with their own rail system on a 3 foot 6 inch gauge, followed in 1879 by Western Australia, the complex jigsaw was completed." - "Great Southern Land: A New History of Australia" by Frank Welsh