Australia-wide, savings of $15.5 billion by 2040 (in 2016 dollars) are identified into Australia's public transport industry by consultants Price Waterhouse Coopers for Infrastructure Australia.

Infrastructure Australia's Improving Public Transport report says: "In Queensland, the savings could help pay for Cross River Rail," but it contains little other data from Queensland.

The report was immediately described as a "political document" by Queensland's Rail, Tram and Bus Union state secretary Owen Doogan.

"There have been two elections where the people of Queensland stand when the issue of the privatisation of public transport system is concerned," Mr Doogan said.

"And both governments got the message that the people don't want it."

The report will however re-open the debate in Queensland about leasing government assets.

The full report will be released on Friday and is the result of 12 months of research by consultants PwC into the impact of letting extra competition into providing public transport services around Australia.

Allowing extra competition into public transport bodies like Queensland Rail - which is wholly-owned by the Queensland Government - and Brisbane Transport run by Brisbane City Council - was a recommendation of the Australian Infrastructure Plan, released in February 2016.

"So in Queensland the savings are just over $3 billion and the bulk of that is from Queensland Rail," Adrian Dwyer, Infrastructure Australia's executive director of policy and research said.

There are already many versions of the model, described as "franchising", operating in south-east Queensland, Sydney and Melbourne, as well as in the United Kingdom and parts of Europe.

In Brisbane, CityCats are franchised to the company TransDev, which is the same company that runs Sydney's Harbour City Ferries.

Brisbane City Council runs about 70 of the city's bus routes and allowing private sector contestability was a policy of the previous LNP state government in 2014.

On the Gold Coast, the successful light rail service is run by the GoldLinQ franchise, which won the tender in May 2011 from the Bligh Labor government.

GoldLinQ is a consortium that includes McConnell Dowell Constructors, Bombardier Transportation and international tram operator Keolis.

Melbourne's trains are run by the Metro franchise, which is a joint venture between the John Holland Group, the MTR Corporation and UGL Rail.

"So it is really not a new idea," Mr Dwyer said.

"There is a breadth of experience across the country."

"And all the rail in the UK is operated in this way."

How franchising works

• Government keeps ownership of buses, trains and ferries, sets timetables, keeps control of buying any new assets;
• Government sets the outcomes and expectation for services including frequency and service routes;
• Train or bus services go out to tender to run the day to day operations;
• Government would announce successful winning tender and sign contract for new operator to run passenger trains and Brisbane's buses; and
• Contracts can vary between 8 and 12 years.

The report says averaged public transport wages were "similar" in Brisbane, Sydney and Melbourne, regardless of public or private operator.

Where do the claimed savings come from?

Mr Dwyer said the PwC research showed savings came from;

• Improved productivity and labour costs;
• Optimising vehicle and carriage configurations;
• Improved scheduling of maintenance;
• Ensuring maintenance facilities are located to avoid empty vehicle running, and;
• Improved network design which optimises routes and fleet utilisation.

The report contained only limited discussion about subsidies paid by government to operators. Fares paid by passengers cover between "20 to 30 per cent" of operating costs.

What do the case studies in the Improving Public Transport study show?

The study predicts an extra 460,000 public transport trips by 2040 in Southeast Queensland, similar to predictions in the latest Cross River Rail project study showing rail commuters will double in 10 years.

In Melbourne

Franchising began in the late 1990s and the on-line running "improved by 2.6 per cent."

Staff numbers dropped from 18,000 to 8400 between 1992 and 1997, saving $245 million.

On-time running worsened between 2003-04 as patronage grew, however it has improved, the study finds.

"Metro Trains Melbourne, have significantly improved punctuality since 2009-10," the report says.

Reliability of train services under Melbourne's franchised system is between 98 and 99 per cent.

In Sydney

Sydney's City Ferries are run by TransDev since 2012, which also runs Brisbane's CityCats.

- "Improved on-time running, consistently achieving 99 per cent of services on-time since taking over the contract."

- "Customer complaints have also declined."

- "In 2014-15 the complaint rate was about 2.2 per 100,000 boardings, which was about 30 per cent lower than the final year of public sector operation in 2011-12."

- "These improvements were made while also reducing the contract price to government by 12% per annum."

What the Rail, Tram and Bus union says.

"It is based on the philosophy of the federal government from 2014 from a government that wanted to privatise," Owen Doogan said.

The report includes sections on the previous federal government's asset recycling scheme.

"We understand there has been no communication with any of the key stakeholders."