The chief executive of the Cross River Rail project has rejected a call for "tunnel stubs" to be built at key points that would add flexibility for future extensions to the rail network.

In October, former CRR planner David Bannister said amendments should be made to the project near Park Road station, near Roma Street station and near the Mayne railyards by March to allow Cross River Rail to be as flexible as possible.

Cross River Rail Delivery Authority Graeme Newton (left) speaks with Transport Minister Mark Bailey and pioneering engineer Professor Else Shepherd.CREDIT:TONY MOORE

He suggested "tunnel stubs" would allow flexibility for the future Acacia Ridge to Port of Brisbane rail freight line.

But Cross River Rail Delivery Authority CEO Graeme Newton, speaking this week during the unveiling of the names of the tunnelling machinery, said the suggested changes were not needed under the new rail track configuration.

There is a range of different options that have been considered in reaching the conclusion of the design that we have got now," Mr Newton said.

"We always welcome views from people who are coming from an informed position, but at the end of the day we are in the process of delivering the design as laid out in the [2019] reference design and that is what we will be doing."

Minerva Transport Planning Company director David Bannister's suggestions were not incorporated in the final Cross River Rail plan.

Mr Bannister, who worked on the Cross River Rail project from 2009 to 2016, released a report that said the project's rail alignment in 2017 was a superior model and could deliver 30 trains per hour across the city.

Mr Bannister said changes to the project design in 2019 meant Cross River Rail could not deliver more than 24 trains an hour.

Mr Newton said the new Cross River Rail project alignment was able to cope with Brisbane's future Acacia Ridge to Port of Brisbane freight line, which was still being planned.

"The current Cross River Rail alignment provides that suburban rail connection through and provides that rapid connection to the city," he said.

"The previous design - which was the longer tunnel design - was servicing a different methodology.

"The present design is giving that additional service through the CBD."

Mr Newton said the newer design provided extra service for the Gold Coast and Beenleigh lines.

"By providing the service for the Gold Coast line and the Beenleigh line directly through the CBD, it provides that underground station accesses."

An artist's impression of the proposed Woolloongabba underground rail station as part of Cross River Rail.CREDIT:

Rail Back on Track spokesman Robert Dow said he disagreed with Mr Newton and believed a rail bottleneck would be created at Dutton Park.

Mr Dow said the earlier "longer tunnel" plan - where the tunnel began at Yeerongpilly, not Dutton Park - allowed the dual-gauge line to become the dedicated freight line through the city.

That plan was changed after concerns were raised about more than 66 Yeerongpilly homes to be resumed.

Mr Dow said the previous model allowed four lines running into and out of the southern end rail portal in addition to the dual-gauge lines, which could be used for rail freight.