Despite the inhospitable nature of the terrain[1] and wartime supply problems, satisfactory progress was made, and the two tracklaying machines, one working from each end, met near Ooldea on 17 October 1917.

It was a matter of misfortune that its two termini were break-of-gauge stations connecting with narrow-gauge lines that formed part of the transcontinental link.

In 1937, the eastern end was extended south to Port Pirie, enabling one less break of gauge in the trip across Australia, but at the same time establishing a three-gauge junction at Port Pirie with the 1,600 mm (5 ft 3 in) broad gauge South Australian Railways line to Adelaide.

Construction of this line was commenced by the Government of South Australia, being known then as the Palmerston & Pine Creek Railway, it opened in 1889.

The railway gained increased importance in the 1960s and early 1970s through the mining of iron ore from the Frances Creek deposits, about 230 kilometres south of Darwin.

In the years following World War II, large tonnages of coal were railed from Leigh Creek and heavy demands were placed on the railway.

The train provided all the supplies for remote towns in South and Western Australia that were mainly inhabited by railway workers who maintained the line.

The Trans-Australian Passenger train ran between Port Augusta and Kalgoorlie that commenced in 1917 and was still being operated by Australian National when it ceased in 1991.

For its standard gauge operations, Commonwealth Railways purchased G, K, KA, C, CA, CN and L class steam locomotives.

For its narrow gauge operations, NC, NSU, NT and NJ diesels were purchased to replace steam locomotives inherited from the South Australian Railways in 1911.