The huge spend was unveiled in federal Treasurer Scott Morrison's second federal budget on Tuesday night and would cover most of its estimated $10.7 billion cost.

Once built, the 1700-kilometre rail link, nicknamed the "Steel Mississippi" by some, would take about 110 B-double trucks off the roads with every train journey.

Cr Antonio said the inland rail would revolutionise business in the Darling Downs, but it also needed to be future-proofed to allow for future use as a passenger route to Brisbane, 140 kilometres to Toowoomba's east.

"We have about 100,000 people in Toowoomba and you'd probably need a bigger critical mass to make it work," he said.

"But I think there's an expectation in Toowoomba that upon the maturity of the inland rail route, where there's probably two lines at least, that we'd be looking towards getting a train to Toowoomba."

Cr Antonio said he and Lockyer Valley mayor Tanya Milligan had put together a proposal for an in-depth study into an extension of the Rosewood line to Withcott, at the base of the range.

With the inland rail, Cr Antonio said, it could go even further.

"As we build this (inland rail) line, I'll be advocating for that capacity to be built into it," he said.

"I think there are times to strike with projects like this and from now on is the time for us to put this on the table and say to the federal government and those who are funding this, 'future-proof this now'.

"They're talking about building a single-line tunnel through the hill. Why wouldn't you at least double that and have at least a two-line tunnel, and maybe a three-line tunnel, to future-proof the project?"

Public transport lobbyist Robert Dow, from Rail: Back on Track, said the inland rail would be a "game changer" for south-east Queensland and urged all three levels of government to explore passenger options using the new tunnels through the ranges.

"The opportunity exists for the state government to run commuter trains to Toowoomba in almost half the time it takes the Westlander train on the existing track and alignment," he said.

"The travel time efficiency savings flowing from the track improvements will make rail highly competitive with cars for the journey from Toowoomba to Brisbane."

The extension of the Citytrain network would not necessarily require expensive electrification, Mr Dow said, as diesel hybrids could be used.

"They can run out the wires to Rosewood then switch over to batteries with a diesel back-up," he said.

"They regenerate, but can run part of the way on battery then flick over to diesel. Japan's got these things already - these things exist."

Transport Minister and Deputy Premier Jackie Trad said while the Queensland government could eventually explore a Toowoomba Citytrain link, the Cross River Rail remained the state's top priority.

"Unless it's built, south-east Queensland will eventually grind to a halt," she said.

"We must act now to make sure our public transport system keeps pace with the rate of population growth.

"We will consider further upgrades and linkages on our Citytrain network but first and most importantly, we need to get on with the job and build Cross River Rail."

As for the freight benefits of inland rail, Cr Antonio said it would "change the way business is done right across this region".

He said it would drive Toowoomba's push to be a major logistical hub and a place where food could be produced and prepared for export around the world.

"Close of 50 per cent of what goes out of the Port of Brisbane comes through Toowoomba, principally on a road system that was built for a different purpose but will be replaced by the bypass soon, and secondly on a rail line that was built just on 150 years ago," he said.

"The reality is, there's not been a lot done to that windy, three-foot-six gauge line in the intervening period.

"... Of the 3.5 million tonnes of primary agricultural product that's produced in this area, only 180,000 tonnes goes out on rail.

"It's just ridiculous when its more competitive in somewhere like Goondiwindi to cart the grain on a B-double train than it is to cart on a train in reasonably sizable loads.

"So the exporters of this region are being disadvantaged terribly by the lack of infrastructure."