Dozens of people with a vision impairment have been left waiting on a Brisbane train platform after the next-generation train they were there to test never arrived.

Queensland Rail (QR) invited between 30 and 40 vision-impaired or blind people to Roma Street Station in Brisbane on Wednesday evening to test the disability access of the new New Generation Rollingstock (NGR) trains.

The new trains have been plagued with problems over their late delivery and issues with braking, air-conditioning and disability access.

Disability access is such an issue the Human Rights Commission has refused the Government's request for an exemption from disability discrimination laws for the trains.

The mistake is the latest in a series of problems with the new trains. ( ABC News )

One of the people invited to the event, 25-year-old Hailey Lindemann, said the group was given an introduction from Queensland Rail staff and were expecting to hop on the new train when it arrived, to familiarise themselves with the new layout.

She said after a delay, the group were told the wrong type of train was turning up.

"[The staff member] was like, 'oh, I'm really sorry — the train that's actually arriving is not the NGR,'" she said.

"I'd just taken a day off work for this — it was a bit of inconvenience for me and obviously the 30 or 40 other people who were there."

'Communication breakdown,' QR says

QR chief executive Nick Easy blamed a "communication breakdown" for the mistake and said the train that arrived was one that many members of the disabled community would have already been familiar with.

"The expectation was to see one of our new trains — I do appreciate that it isn't a good look, and we'll rectify it," Mr Easy said.

All 21 NGR trains so far delivered had significant defects. ( Supplied: Transport and Main Roads )

A number of refugees and migrant students had also been invited to the event, to familiarise themselves with Brisbane's train network.

Ms Lindemann said she was at the back of the group on the platform and could not hear staff members explain what had happened to the train, so she and a group of friends chose to leave.

"We've just wasted our day — we're not going to waste it even more," she said.

Ms Lindemann said she was quite independent on trains and often asked other passengers for help to find a seat or the door buttons.

"But there are lots of other people who are not just blind, but are in wheelchairs and they haven't got that mobility," she said.

Mr Easy said passengers with a vision impairment would be given another opportunity to come and test the train.

But Ms Lindemann said she was sceptical.