There is currently no rail link to Edinburgh Airport

Members of the Edinburgh Airport Rail Link (Earl) Bill committee agreed that the line could help reduce traffic.

But they voiced concerns about how the proposed railway line to Edinburgh Airport would be funded and the cost of rail journeys.

Air passenger numbers are set to rise massively by 2030, so it is hoped that a rail link could cut road congestion.

The committee is set to take further evidence from Transport Minister Tavish Scott, the bill's promoters, Transport Initiatives Edinburgh (Tie Ltd), Transport Scotland, Network Rail and Edinburgh Airport Limited.

Premium fares

Despite the concerns raised, a majority of MSPs on the committee agreed the bill should go forward.

Convener Scott Barrie said: "We are satisfied that the rail link could provide a beneficial service to the ever-increasing number of passengers using Edinburgh Airport.

"It will go some way to alleviating future congestion on the roads surrounding the airport."

But he added that the committee was concerned about the extent to which these benefits could be realised.

The massive costs of this scheme can be put to far better use Fergus Ewing SNP

The MSP said: "We remain extremely concerned that a premium fares policy may be adopted by Transport Scotland which could unfairly penalise those travelling to the airport from outwith Edinburgh.

"The committee also remains frustrated that it has not been able to confirm in any detail what funding is in place to construct the Earl scheme."

The SNP's transport spokesman Fergus Ewing said: "The SNP does not believe that this scheme represents value for money.

"The current proposals would mean a tunnel would have to be made under the live runway, which would require train engines of a power that do not exist on the Scottish rail network.

"The massive costs of this scheme can be put to far better use and we will outline our proposals on this soon."

He added the party would consider alternative routes for a rail link between Waverley station and the airport which did not involve "burrowing under a runway".