This is despite a feasibility study never having been done analysing the service.

TasRail spokeswoman Jenny Jarvis said expansion of tourist and heritage rail passenger services on to the state's freight lines was also years away, with a review to be held in two or three years.

TasRail, Tourism Tasmania, and tourist and heritage rail operators investigated opening the state's rail network to tourism services last year.

The review found operating a tourist service off the main line could not be done in the short to medium term without compromising the safety and integrity of the state's rail assets.

Ms Jarvis said general passenger trains, such as a Hobart-Launceston service, was more complex and expensive, involving high-cost infrastructure like stations, as well as rollingstock.

She said transit time would likely be longer than road travel, making it a far less popular option.

``It is difficult to see that passenger travel could ever be financially viable or utilised to a sustainable level,'' Ms Jarvis said.

Tasmania's rail network is 845 kilometres long but 213 kilometres of this is non-operational.

Public transport advocacy group Future Transport Tasmania plans to prepare a costings report for a Hobart-Launceston passenger rail service.

Spokesman Toby Rowallan believes the cost of the service would be significantly less than the cost of a dual carriageway on the Midland Highway - a Liberal Party commitment should it win government at next year's federal election.

He said a four-lane highway would likely cost at least $5 billion, not the predicted $2 billion.

Mr Rowallan based this figure on the $51 million Kingston Bypass project, which installed just two kilometres of single-lane highway.

He said a rough estimate of the realigned rail line between Hobart and Launceston would likely come under $3 billion.

Mr Rowallan said that the state could buy trains that ran at speeds of 200km/h to reduce travel time between the two centres.

``If a four-lane Midland Highway is on the table, so should an alternative,'' he said.

``We believe that the alternative is far more cost effective, more attractive and safer.

``Of course this is not a money-making proposition . . . however, we are of the firm belief that while this may not be viable in terms of a financial return, neither is the four-lane carriageway.''