A narrow gauge railway was built from Port Pirie to Gladstone, Peterborough and Broken Hill, in 1888 to serve the Broken Hill silver and lead mine, which was becoming the largest and richest of its kind in the world. Since the New South Wales Government would not allow the South Australia railway to cross the border, the last 30 km was built by a private company as a tramway, the Silverton Tramway from Cockburn to Silverton and Broken Hill. In 1970 the line was converted to standard gauge, completing the standard transcontinental gauge line from Sydney to Perth.