The minister announced two air-rail links

Transport Minister Iain Gray said the �368m project for Edinburgh would see the construction of a rail tunnel under the runway.

There would be the potential for up to 12 trains per hour with services to Edinburgh Waverley, Glasgow, Fife, Aberdeen, Stirling and Newcastle.

If the project gains parliamentary and planning approval, the link could be operational by 2010.

This is the first step to improve Scotland's rail infrastructure but more progress is still needed Ian Hogarth, CBI Scotland

Glasgow Airport would have a connection to the city's Central Station via Paisley and the anticipated journey time would be 15 minutes, with up to four trains per hour.

The minister also promised improvements to Prestwick Airport in Ayrshire and the connections to Inverclyde, Renfrewshire and Ayr.

The anticipated completion date for the �105m project has been given as 2008.

He said �5m and �3m would be made available to Transport Initiatives Edinburgh and Strathclyde Passenger Transport (SPT) respectively to begin preparations for the developments.

Any vote on the proposals would have to be put before MSPs after the elections on 1 May.

Mr Gray said: "These links will offer real transport improvements not only to those visiting Scotland on business or on holiday, but also for the hundreds of people who pass through these airports on their daily business."

Iain Gray promised "real improvements"

SPT chairman, Councillor Eric Ross, said the Glasgow project would mean "huge business and tourist benefits" as well as faster and more frequent services.

CBI Scotland said the proposed investment was a step in the right direction.

Ian Hogarth said: "What is important is that other moves, for example, to upgrade Waverley Station, aren't ignored.

"This is the first step to improve Scotland's rail infrastructure but more progress is still needed."

Edinburgh Councillor Andrew Burns said the capital's line would provide passengers with access to the heavy rail network in Scotland.

He said: "You'll be able to get a direct train up to Aberdeen, across to Glasgow or even down to Newcastle and that's of very great benefit to the tourism industry in Edinburgh which is very important to the whole of the east coast of Scotland.

Scottish Tory transport spokesman David Mundell MSP said: "This is yet another electioneering announcement, and coming only seven weeks away from an election the Scottish public - like the Scottish Conservatives - will be understandably cynical about it."

He accused the executive of "dragging its feet" over much-needed improvements to the network.

Concerns have been raised by some consultants over the costings for a Glasgow link.

They said the Edinburgh link would be financially viable, because there would be substantial demand from the city centre.