A Transport Scotland spokesman said:
"In response to the delivery date of the Borders project, we are currently finalising the commercial terms of the contract with Network Rail for handover to them of the scheme delivery, and expect to conclude those discussions later this month.
"The Borders Railway will re-establish passenger railway services for the people of Edinburgh, Midlothian and the Scottish Borders for the first time in over 40 years, delivering real economic and social development opportunities, and offering a fast and efficient railway that will be a real alternative to the car."
They add that the current scheme costs are £235-£295m at 2012 prices.
More top news
Scottish leader Johann Lamont's resignation highlights the post-referendum divisions.
Remaining windy in the west. Heavy rain on Sunday morning
A consultation is to begin in Melrose to look at the possibility of charging for car-parking all year round in the town's main car park.