When Beeching's axe cut through the Waverley line it disastrously severed a vital link between the Borders and much of Midlothian from the city of Edinburgh.

Four decades on, industrial, political and social changes have made the 30-mile route joining the former mill towns and mining villages with the Scottish capital a viable prospect once again.

The signing of a deal with Network Rail yesterday brings clarity to the project which has been subject to uncertainty as costs escalated and the tendering process collapsed when all but one private contractor pulled out.

Work should have begun by now but the shadow of the Edinburgh trams debacle should provide a salutary warning against too much complaint about delay when it is more important to ensure a contract that will deliver to an agreed timetable and price. The Scottish Government's costs have risen by more than £50 million to £350m. Network Rail's £294m contract, to be funded through it own borrowing powers, is said have reduced previous estimates by about £60m.

An increase in costs is inevitable due to the time lapse but the project has also been revised to enable tourist trains to call at Tweedbank station south of Galashiels. Such provision is essential: major infrastructure projects must benefit as many people as possible if they are to provide full value for the investment required.

The loss of the railway link was a cruel blow to the Borders economy. Although only about 40 miles from Edinburgh, the hilly terrain is an obstacle to a fast road connection. The Borders towns have suffered the closure of many traditional textiles businesses but have been unable to benefit much from Edinburgh's buoyant economy because of the long commuting time. A train journey of under an hour will change that. At the same time, Edinburgh's high house prices are causing more people, especially first-time buyers, to move out of the city. A good rail connection will attract commuters, particularly young families, to all the towns and villages south of the capital, giving them a much-needed population boost, which will benefit local businesses.

Cutting 60,000 peak-time car journeys a year will be significant in reducing accidents and cutting carbon emissions.

As well as bringing inward investment to the area, Transport Minister Keith Brown expects the Borders railway to benefit the wider Scottish economy by £33m. That remains to be seen but there will be great potential for increased tourism. Businesses and Scottish Borders Council should lose no time in capitalising on the renewed interest in knitwear and tweed to ensure there are top quality attractions ready for visitors in 2015. After 11 months of planning and negotiation, both Transport Scotland and Network Rail must ensure that first train arrives on time.