The High Speed Rail Authority, a federal government agency established in 2023, has been tasked with "advising on, planning, developing and overseeing the construction and operation of a transformational network along Australia's eastern seaboard".

The authority's first priority is planning and corridor works for the Sydney to Newcastle section of a high-speed rail network, backed by a $500 million commitment from the Australian Government.

[10][11][12][13][14][15][16][17][18] Although such studies have generated much interest from the private sector and captured the imagination of the general public upon their release, to date no private-sector proposal has been able to demonstrate financial viability without the need for significant government assistance.

[23] The train is not often used to its full potential, operating along winding steam-era alignments,[24] and at times has had its top speed limited due to track condition and level crossing incidents.

[27] Safety-related issues, signal deficiencies & the retrofitting of train-stop mechanisms to power cars in 2006 resulted in XPT speeds being limited to 115km/h on Sydney's electrified network.

[35] Subject to effective project management, the future New South Wales R set (XPT replacement) may also suffer the same restrictions if the operator does not resolve the current outstanding issues.

In October 2010 Downer Rail was awarded a contract to build a further diesel tilt train with two power cars and 12 carriages to replace locomotive hauled stock on The Sunlander.

The 1979 Premiers' Meeting proposed the electrification of the Sydney–Melbourne line to improve transit time from over 12 hours to under 10, but a senate committee found this was not justified on economic grounds.

However, it proposed only the strengthening and partial electrification of the existing tracks, new deviations to bypass the worst sections, additional passing loops, and the purchase of new diesel-electric trains.

Two years later in September 1986, the Very Fast Train Joint Venture was established, comprising Elders IXL, Kumagai Gumi, TNT and later BHP, with Dr Wild as chairman.

In January 1990 it was reported that the NSW government was considering upgrading the existing state railway lines to utilise tilting train technology under development by Swedish-Swiss engineering giant ASEA Brown Boveri.

[60] The greatest challenge was the carriages' relatively wide clearance profile, which necessitated a targeted program of platform cutbacks and track slews on the Sydney-Canberra route.

[60] In 1993, the Speedrail Consortium (a joint venture between Alstom and Leighton Contractors) made a proposal for a high-speed rail link between Sydney and Canberra.

In December 2000 in the wake of the termination of the Speedrail proposal, the Howard government commissioned TMG International Pty Ltd, leading a team of specialist subconsultants, including Arup, to investigate all aspects of the design and implementation of a high-speed rail system linking Melbourne, Canberra, Sydney and Brisbane.

In March 2002, the Government decided not to go ahead with phase 2 of the scoping study due to the finding that an enormous amount of public funding would be required for the massive infrastructure project.

The initiative was supported by both the Liberal opposition and the Australian Greens, the latter of which called for the study's scope to be extended to encompass Adelaide and Perth,[71][72] a sentiment that was echoed by some.

Much of the reduction came through making greater use of existing transport corridors for metropolitan access; the government study took the politically uncomplicated but extremely expensive option of simply tunnelling to the terminal stations.

The document explained that as of 2022, their cost estimate for the Melbourne-Sydney-Brisbane HSR corridor was between $200 and $300 billion - significantly higher than the $114 billion cost outlined in Phase 2 of the High-Speed Rail Study - due to reasons including that:[120] In September 2022, the then-recently elected Albanese government introduced legislation to establish a new national High Speed Rail Authority (HSRA), fulfilling a promise made during the 2022 election.

[121][122] The Infrastructure Minister Catherine King said the Authority would have an expert board and be tasked with overseeing "the construction and operation of a high-speed rail network along Australia's eastern seaboard" between Melbourne, Canberra, Sydney and Brisbane.

[124] On 26 August 2024 the Minister for Infrastructure, Transport, Regional Development and Local Government Catherine King announced that work was being conducted by the High Speed Rail Authority on determining the locations for this project, utilising thirty boreholes for this purpose.

[125] On 30 January 2024, it was announced that $78.8 million of funding would be released for the development of a business case for the Sydney to Newcastle section of the high-speed rail network.

[129][130] In January 2023, advocacy group Fastrack Australia published a plan that proposed gradually upgrading the Sydney-Melbourne corridor, instead of building a completely new line from scratch.

[131] At various times, state political parties and others have proposed schemes involving fast trains in other localities that included the potential to achieve speeds above the 200 km/h threshold.

The concept was re-proposed in December 2006 by then federal Opposition Leader Kevin Rudd during a visit to Penrith, as part of the Australian Labor Party's election platform.

[133] The line was also backed by a consortium led by union leader Michael Easson, which includes Dutch bank ABN AMRO and Australian construction company Leighton Contractors.

In 2008, Transrapid made a proposal to the Government of Victoria to build a privately funded and operated magnetic levitation (maglev) line to serve the Greater Melbourne metropolitan area.

The route would follow the existing narrow gauge Mandurah line to Anketell, then the Kwinana Freeway and Forrest Highway to Lake Clifton, including 140 km (87 mi) of new track.

[74][138] The 2010 Infrastructure Partnerships Australia report identified Noosa-Brisbane-Gold Coast as a potentially viable high-speed rail link, and a possible precursor to a full east-coast system.

[139] The report predicted that a 350 km/h (220 mph) system would reduce travel times between Cooroy (22 km west of Noosa) and Brisbane to 31 minutes (currently 2:08 hours), capturing as much as 84% of the total commuter market.

Soon after winning the 2011 New South Wales state election, the incoming Liberal premier Barry O'Farrell advocated high-speed rail lines to Melbourne and Brisbane instead of a second Sydney airport, saying of a new airport site in NSW: "Whether the central coast, the south-west or the western suburbs [of Sydney], find me an area that is not going to end up causing enormous grief to people who currently live around it".