CH2M Hill Inc. has won a program and construction management contract for the Massachusetts Bay Transportation Authority’s rebooted Green Line Extension. The $57-million design-build contract is the project’s largest since the scaled-down, $2.3-billion expansion halted two years ago after costs skyrocketed $1 billion over budget. The Federal Transit Administration, which has pledged $1 billon for the project, greenlighted the new estimated cost structure in April. CH2M will be responsible for design-build proposal review and evaluation as well as estimating and scheduling services, quality control and quality assurance. Three months ago, the authority short-listed three design-build teams: GLX Constructors, Green Line Partners and Walsh Barletta Granite JV. It will issue a final request for proposals on May 23. Bids are due in September for work to begin in February.