The RMT says their future remains uncertain because there is no guarantee of long-term funding.

Several South West branch lines have been named as pilot community rail projects - including the Tamar Valley line between Plymouth and Gunnislake.

The idea is to give local people more say about how the railway is run.

In effect their viability will be decided over the next five years, although the government says community rail lines will be given every chance to succeed.

"This is not a small, little model railway where you're showing people a new steam train" - Bob Crow, RMT

General Manager of the Association of Community Rail Partnerships (ACORP) Paul Salveson said: "We want to see the RMT and other unions playing a full part in these partnerships.

"They're certainly not a threat - they're a great opportunity for local railway staff."

The RMT is uneasy at the prospect of community railways being funded by local businesses and councils, without - it says - any long-term guarantees.

It believes the lines are being floated away from the main network, with the prospect of maintenance standards being downgraded and buses replacing trains.

General Secretary of the RMT Bob Crow said: "It's all very good volunteers trying to make the rail network work better, but what we would say is that staffing of these lines has got to be by professional, dedicated staff employed by railway companies.

"This is not a small, little model railway where you're showing people a new steam train."