Track laying has begun on Scotland’s 48km-long Borders Railway.
Network Rail said this phase of the £294M project will be completed in two months.
The line is scheduled to open in September 2015.
Network Rail expects to lay 1km of track a day onto 90,000 sleepers along the route.
A ceremony was held at Shawfair station to mark the official start of this phase of work.
Network Rail chief executive Mark Carne, who joined transport minister Keith Brown for the event, said: “By the end of the year, rails will connect seven stations along the route to the national network for the first time in 45 years.”
Bam Nuttall is contractor for the project.
The scheme is the longest new railway in Britain apart from the Channel Tunnel Rail Link for more than 100 years.
It will reconnect Edinburgh with Tweedbank, south of Galashiels, after the Waverley Line to Carlisle was closed as part of the Beeching cuts in 1969.
Remaining work includes signalling, and construction of the stations at Shawfair, Eskbank, Newtongrange, Gorebridge, Stow, Galashiels and Tweedbank.
Brown said: “With construction due to complete next summer and the line to enter service on 6 September, the new railway will offer a fast and efficient alternative to the congested local road network, allowing passengers to travel from Tweedbank to Edinburgh in around an hour at peak times.“