A multi-billion-dollar contract to build new trains for Queensland was flawed from the start, leaving all 75 new trains not complying with disability access laws, an inquiry has found.

Key points: NGR project suffered an "evolution of failures right throughout", Mr Forde found

NGR project suffered an "evolution of failures right throughout", Mr Forde found Rectification work on the trains will cost $335.7m and take until 2024

Rectification work on the trains will cost $335.7m and take until 2024 All of the rail inquiry's 24 recommendations were accepted by the Government

Retired District Court judge Michael Forde conducted the inquiry into the procurement of the 75 trains, and their failure to comply.

Mr Forde found the initial design, signed off by the Newman government in 2013, broke the law, but was still approved for construction.

The $4.4 billion New Generation Rollingstock (NGR) project was manufactured in India by a consortium led by the company, Bombardier.

But the NGR trains failed disability access tests, including having space for wheelchairs to move into the aisle.

Mr Forde found the delivery of the trains was doomed "from day one" and problems were known "when the contract was signed".

Geoff Trappett from disability advocacy group Inclusion Moves said the fact the trains were flawed from the beginning shows a lack of respect for people with a disability.

"It's just not good enough in this day and age. People with a disability have rights to travel on trains and have right to inclusive transport," he said.

"The issue of the rectification timeframe is one that really angers people with a disability.

"We notified the Government of these issues some years ago — in late 2015 — so that rectification had started then. Then we would be nearing the end of the rectification work, so it's simply not good enough to have non-compliant trains on the track for another six or seven years."

Mr Forde found an "evolution of failures right throughout" the process, which began under the Bligh government and continued under the Newman government.

The project began in 2008, but the first train was not delivered until 2017.

"This procurement took four years longer than it should have," Mr Forde told a media conference, standing beside Premier Annastacia Palaszczuk.

"It was the subject of change, not only as to who led the procurement, but also there were changes of government and also changes of the model from a traditional procurement to the public private partnership."

The NGR development process suffered an "evolution of failures", Mr Forde found. ( Supplied: Transport and Main Roads )

Mr Forde said the nub of the problem was a failure to properly consult with disability groups at the start of the process, which led to the correct disability access requirements being left out of the contract.

"There would have been people at middle to lower management who didn't escalate the problems, and perhaps were just afraid of giving bad news at different stages," he said.

"People with a disability have a right to use our public transport system and should not be at a disadvantage."

The State Government will spend $335.7 million to install a second toilet on all of the trains, and increase the size of existing toilets by 10 per cent.

The work will be carried out by Downer EDI in Maryborough.

Transport Minister Mark Bailey said rectification work would not begin until late next year, with the first of the revamped trains to be put into service in early 2020.

It will take until 2024 for all of the new trains to be disability compliant, under the Human Rights Act.

The report made 24 recommendations, which had all been accepted by the Government.

LNP leader Deb Frecklington said she joined with disability advocates in saying enough was enough.

"This process has run for 10 years — in which Labor have been in charge for seven. It is time for Annastacia Palaszczuk to accept responsibility and deliver these trains," she said.