Cockburn ( KOH-bərn) is a town and locality in the east of the Australian state of South Australia immediately adjacent to the border with New South Wales near Broken Hill. It was established because the New South Wales government refused to allow locomotives of the South Australian Railways to operate in its jurisdiction, requiring locomotives to be changed at the town for 84 years until 1970, when the route was converted from 1067 mm (3 ft 6 in) to 1435 mm (4 ft 8+1⁄2 in) standard gauge.