Commission into grain storage, handling and transport. This particularly affected South Australian railways because of the short distances between the growing areas and its various wheat exporting ports. The Snowtown to Wallaroo Broad Gauge was converted to Dual Gauge (Standard/Broad) during the late 1980s. North Mount Lofty Ranges lines A line was built from Balaklava to Brinkworth and Gladstone by 1880 and later extended to Wilmington. The Hamley Bridge – Balaklava – Brinkworth – Gladstone line was converted to broad gauge in 1927, making Gladstone a break-of-gauge junction. In 1969, when the line from Port Pirie to Broken Hill was converted to standard gauge, Gladstone became a three-gauge break-of-gauge junction (together with Peterborough and succeeding Port Pirie, which had been reduced to two gauges). In the 1980s, the broad gauge line north of Balaklava and the narrow gauge line were closed, leaving Gladstone as a purely standard gauge station. A narrow gauge line was built from Terowie to Peterborough in 1881, creating a break-of-gauge at Terowie, although the enforced train change created an opportunity for General Douglas MacArthur to deliver his famous line "I shall return" at Terowie station on 20 March 1942. The break-of-gauge was not overcome until the Terowie – Peterborough line was converted to broad () gauge in 1970, to meet new the standard gauge from Port Pirie to Broken Hill, but it was abandoned by 1988. The narrow gauge line was extended to Orroroo also in 1881 and Quorn in 1882, connecting with the new line from Port Augusta. This line has now been abandoned. 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 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. The Great Northern Railway The Great Northern Railway was completed from Port Augusta across the Pichi Richi Pass to Quorn in 1879, Hergott Springs (now known as Marree) in 1883 and Oodnadatta in 1891. It was extended to Alice Springs by the Commonwealth Railways in