Australia, as an island continent, is unique in that it has two railroads that cross the entire continent. One, running east-west, joins the Pacific Ocean at Sydney to the Indian Ocean at Perth, 4,352 kms (2,704 miles) apart. The other, running north-south, joins the Timor Sea in the tropical north at Darwin to the Southern Ocean at Adelaide, 2,979 kms (1,851 miles) apart.
The construction of both rail links had to overcome problems caused by the distances to be covered, the extreme high temperatures, the lack of water and the sparse population.

Both lines are single track with passing loops every 30 to 60 kms (19 to 37 miles). Each loop can hold trains up to 1.8 kms (1.1 miles) long. Increasing traffic demand has led to the construction of additional passing loops. Most of the loops are radio controlled (from the locomotive cabs) and are equipped with self-resetting points with solar cells and batteries supplying the necessary power. The traffic on both lines is controlled from Adelaide.
Both links are heavily used by freight traffic running between Sydney, Adelaide, Perth and Darwin with traffic also coming in from other centres on the national standard gauge rail network.
The East-West Link:
The east-west link, originally known as the Trans-Australia Railway, was started in 1912 and was completed in 1917. It initially only joined the port town of Port Augusta in South Australia with the gold mining town of Kalgoorlie in Western Australia, a distance of 1,711 kms (1,063 miles). The line has the longest stretch of dead straight track in the world – 478 km (297 miles) without a single curve.The line was built to the standard gauge of 4ft 8 ½ inches but the railroads it connected at both ends were narrow gauge, 3ft 6in, so passengers and freight had to be moved between trains at both ends to complete their journey.
In the 1970s the lines at both ends were converted to standard gauge so freight and passengers could make the coast-to-coast trip without changing trains. One passenger service, the “Indian-Pacific”, now regularly makes the full journey between Sydney, Adelaide and Perth taking about 75 hours for the trip.

The North-South Link:
The north-south link was started (and repeatedly stopped and restarted) in the late 1870s. It initially started at both ends. The line heading north from Port Augusta was known as the Central Australia Railway, and the line heading south from Darwin was known as the North Australia Railway. Both lines were built using narrow gauge track.

The Central Australia Railway was extended, during the next 50 years, to eventually reach the inland town of Alice Springs by 1929, a distance of 1,220 kms (758 miles) from Port Augusta. Alice Springs is the closest town to the geographic centre of the continent.
The line was plagued by reliability problems as the track and bridges were frequently washed out by flash floods. The southern 350 km (220 mile) section of this line from Port Augusta was the most heavily affected by flood damage. This was replaced by a standard gauge track on a new alignment that bypassed the flood prone areas in the late 1950s. Passengers and freight had to change to narrow gauge trains at the end of this section to continue their journey. There were vague plans to eventually extend the standard gauge track all the way to Alice Springs.
The narrow gauge Central Australia Railway and its southern standard gauge section were closed when the current standard gauge line was built from Port Augusta to Alice Springs on a completely different alignment in 1980.

Construction of the North Australia Railway stopped just over 300 miles south of Darwin in 1929. The line saw little traffic, averaging only a few trains a week until World War II when plans were drawn up to link the line to the Central Australian Railway at Alice Springs, nearly 1,000 kms (620 miles) further south. But the end of the war also saw the end of this plan. For a few years mineral traffic kept the line open but in 1976 it was permanently closed.
In January 2001 the construction of the current line from Alice Springs to Darwin was started, about 130 years after it was originally proposed. The first standard gauge freight train rolled into Darwin from Adelaide in July 2004. One passenger service, “The Ghan” named after the Afghan camel drivers who drove the camel trains along the original route, regularly runs between Darwin, Alice Springs and Adelaide.
Contributed by pware