In addition to advanced preliminary design services, the joint venture will provide final design services and services during construction in future phases of the contract for a number of elements, including seven new stations and 4.5 miles of light-rail tracks; the relocation of Lechmere station; the reconstruction of bridges along the corridor and the development of a new maintenance and transportation facility.

"We are proud to partner with the MBTA on its first expansion project in 25 years, which also is currently the largest infrastructure project in Massachusetts," said AECOM Chairman and Chief Executive Officer John Dionisio. "Our local light-rail expertise, as well as our direct experience with the entire MBTA system, position AECOM well to help improve Green Line service for Boston's residents and visitors."

The extension project is expected to improve air quality and travel times within the corridor, as well as reduce automobile congestion.