Rail transport in Australia is a component of the Australian transport system. It is to a large extent state-based, as each state largely has its own operations, with the interstate network being developed ever since Australia's federation in 1901. , the Australian rail network consists of a total of of track built to three major track gauges: of standard gauge (1435 mm / 4 ft 8 in), of broad gauge (1600 mm / 5 ft 3 in), and of narrow gauge (1067 mm / 3 ft 6 in) lines. Additionally, about of 610 mm / 2 ft gauge lines support the sugar-cane industry. , around 11 per cent of the Australian heavy railways network route-kilometres are electrified. Except for a small number of private railways, most of the Australian railway network infrastructure is government-owned, either at the federal or state level. The Australian federal government is involved in the formation of national policies, and provides funding for national projects. National issues Uniform gauge Very little thought was given in the early years of the development of the colony-based rail networks of Australia-wide interests. The most obvious issue to arise was determining a track gauge. Despite advice from London to adopt a uniform gauge, should the lines of the various colonies ever meet, gauges were adopted in different colonies, and indeed within colonies, without reference to those of other colonies. This has caused problems ever since. Attempts to fix the gauge problem are by no means complete. For example, the Mount Gambier line is isolated by gauge and of no operational value. Electrification With the electrification of suburban networks, which began in 1919, a consistent electric rail traction standard was not adopted. Electrification began in Melbourne in 1919 using 1500 V DC. Sydney's lines were electrified from 1926 using 1500 V DC, Brisbane's from 1979 using 25 kV AC, and Perth's from 1992 using 25 kV AC. There has also been extensive non-urban electrification in Queensland using 25 kV AC, mainly during the 1980s for the coal routes. From 2014 Adelaide's lines are being gradually electrified at 25 kV AC. 25 kV AC voltage has now become the international standard. History The first railways in Australia were built by private companies, based in the then colonies of New South Wales, Victoria and South Australia. The first railway was privately owned and operated and commissioned by the Australian Agricultural Company in Newcastle