The Mass Rapid Transit Authority of Thailand board on Friday approved the construction of a line from Mor Chit to Khu Kot with bids to be called early next year.
The estimated cost of the 28-kilometre Green Line is 29 billion baht. Bids will be divided into four contracts, board chairwoman Ratchanee Treepipatkul said after the meeting.
One contract involves civil work including the building of 12 stations for an 11km sector from Mor Chit to Saphan Mai, and another one for 7km with four stations from Saphan Mai to the end of the line.
The third contract will be for car park buildings and a maintenance centre, and the last one for the electric rail track system.
Miss Ratchanee said bidding was expected to open early next year and all contracts were expected to be signed by mid-2014.
Construction would take four years and the line would be ready for service in 2018, she added.
It is the second time that the board has approved the project. The MRTA endorsed the line in December last year but further adjustments were called for, including the relocation of the Lak Si Monument.
The Green Line will connect with the present BTS skytrain line at Mor Chit.