Engineer Edwin Mitchell has developed the plan for the Cooma and Monaro Progress Association, which is now commissioning a preliminary cost estimate as part of a full business case that it will use to push for government funding.

Mr Mitchell says that rather than waiting for a high-speed railway from Canberra to Sydney, his plan would open up areas of untapped potential, with the capital to reap the benefits of a rail link with the deep-water port of Eden.

"Canberra Airport could position itself as the gateway of choice for both air-freight and passenger travel for virtually the entirety of southern regional New South Wales, and perhaps much of eastern Victoria," he writes in the concept plan.

Mr Mitchell says now is a good time to realise the "century-old dream", with freight customers looking for alternatives to the major transport routes into Sydney, which are reaching or nearing capacity, while also expensive, slow, or both.

The plan proposes to rebuild the disused rail line between Queanbeyan and Bombala to a higher standard, extending it north to include a stop at Canberra Airport.

The proposed line could split into three potential routes as it heads south towards Eden, with one route going to the port town via Bombala and Nungatta.

The other two possibilities are a line passing through Bombala and Wyndham, or one that would go through the Bega Valley.

Passenger rail journeys would be about 30 per cent faster on average than driving, with Canberrans able to reach Cooma in 52 minutes, Bombala in 93 minutes and Eden in 139 minutes.

Snowy Mountains Regional Council Mayor John Rooney said the plan was "visionary", and that no project would have a greater transformative effect on the region.

Mr Rooney said several small towns in south-east NSW had stagnated since the state government closed the Queanbeyan to Bombala railway line 30 years ago, and that while passenger trains on the route would create "one of Australia's great railway journeys" and boost tourism, the biggest benefits would be in freight.

"We would love to be able to take greater advantage of Canberra Airport to export, and this project would connect the airport with the Eden sea port, making it the major freight route in south-eastern Australia," he said.

"The lack of transport has hampered many economic opportunities for the traditional industries in towns along the route."

Mr Rooney said he could envision a "booming" manufacturing industry at Cooma's under-utilised Polo Flats if the railway line went ahead, with the prospect of goods produced there being exported from Canberra Airport.

He also said transporting freight by rail would greatly reduce the cost of road maintenance for governments and councils.

Member for Monaro and NSW Deputy Premier John Barilaro said with the state government planning to invest the proceeds of Snowy 2.0 in infrastructure, there was "definitely scope" for projects like a Canberra to Eden railway line.

Mr Barilaro said he planned to meet with NSW Transport Minister Andrew Constance, who is also the Member for Bega, to discuss the viability of the project.

"It is something I am interested in, but it must be thought out and realistic," Mr Barilaro said.

Fairfax Media asked Chief Minister Andrew Barr's office whether the ACT government had discussed supporting the process and chipping in funding if it became a reality.

With Mr Barr currently in Singapore, a spokesperson for Acting Chief Minister Yvette Berry responded by saying the government had not yet closely considered the plan, but was "always interested in improving transport in and out of Canberra".

"This proposal would support the case for Canberra to be the freight hub of the region, absorbing excess freight from Sydney and Melbourne," the spokesperson said.

The spokesperson said the ACT and NSW governments were committed to continuing their push for improvements to the Canberra to Sydney rail line, despite the Commonwealth government deciding not to support their joint application for business case funding.

Canberra Airport director of planning and government relations Noel McCann said the airport had received a briefing on the concept plan and looked forward to receiving more information.

"We continue to support more efficient ground transport for passengers and freight, including rail, throughout our region," Mr McCann said.

- Canberra Times