With owner Pacific National saying the railway is no longer an economically viable proposition, it is in danger of closing without substantial State and Federal Government assistance.

Department of Infrastructure Energy and Resources secretary Mark Addis said the claim presented by Pacific National amounted to $120 million over 10 years, but it had not been supported by a business case.

"From a government perspective, we can't do business that way," Mr Addis said.

Mr Addis said the State and Federal Governments had agreed to jointly fund an independent assessment into whether a case for public money being put into a private company could be justified.

If it was, then the Government needed to consider all the options. He said the assessment was being fast-tracked and should be completed by the end of next month.

Transport economist Bob Cotgrove said railways had a legitimate case for seeking assistance for the public benefits they provided.

Both State and Federal Government had an obligation to compensate Pacific National for diverting container freights from the road network, and for infrastructure investment just as governments did for roads.

Pacific National's Tasmanian chief executive officer, Neil MacKinnon, said there was no guarantee the company could maintain all services during the duration of the study if there were more locomotive breakdowns but it was keeping its customers informed.

Opposition Leader Rene Hidding released a draft plan for discussion which proposed title of the rail lines, ballast and sleepers, which Pacific National bought for $22 million, should be bought for $1 and be vested in the Tasmanian Ports Corporation.

He said the Federal Government should provide $78 million over 10 years for infrastructure funding and the State Government $40 million over 12 years.

Infrastructure, Energy and Resources Minister Bryan Green said Mr Hidding was shooting from the hip.

"Federal Minister Warren Truss must be livid that his state colleague would commit the Commonwealth to spend $78 million on a private operation without even a phone call to Canberra," Mr Green said.

Rail, Tram and Bus Union organiser Greg Harvey said it was a sad indictment on the Federal Government that it had not sent a representative to the forum.