The £220m contract includes detailed design and construction works for the new line and will see around 500 jobs created by the project between now and 2015.
The Borders Railway, which will enter service in 2015, will re-establish a passenger rail link for the first time in more than 40 years from Edinburgh through Midlothian to Tweedbank.
The line will include 30 miles of new railway with three existing stations and seven new ones – at Shawfair, Eskbank, Newtongrange, Gorebridge, Stow, Galashiels and Tweedbank.
Network Rail route managing director for Scotland David Simpson said: “The appointment of BAM Nuttall as our main contractor signals the start of the delivery of the new railway for the communities it will serve. BAM Nuttall has already been working closely with Network Rail in drawing up initial designs for the new line and can now carry that momentum into the delivery of the main construction phase as we work to complete the new line for the start of services in 2015.”
BAM Nuttall chief executive Stephen Fox added: “This scheme brings together the engineering strengths of the BAM Group and will create significant local employment opportunities. In addition it will provide a much needed rail link to those rural communities living in the Scottish borders region”.
Once complete, passengers will be able to travel direct from Tweedbank to Edinburgh Waverley in less than an hour at peak times.
Construction of the line will begin in early 2013 and complete by the summer of 2015. The capital construction cost of the line will total £294m, at 2012 prices.
Construction work will take place simultaneously along the line of route, centred on three main project hubs in Fountainhall, Tweedbank and Monktonhall.
BAM Nuttall will hold a ‘meet the buyers’ event to engage with local suppliers before construction works start.