Network Rail and principal contractor BAM Nuttall last week began main construction work on the new Borders Railway line.
The first works will involve the excavation of the track alignment for the new line through Monktonhall and the excavation of the site of the new Shawfair station.
The earthworks programme, which will create the base for the railway track, will now begin to roll-out along the route throughout summer and autumn.
Council Leader Councillor Bob Constable said: “This is an important day for us all in Midlothian.”
A £249 million project, the Borders Railway is expected to open in 2015, more than 40 years after the line was closed.
Read more on this in the April 25 edition of the Midlothian Advertiser.