The MBTA announced [yesterday] it will begin a series of major crane lifts this weekend at the new Lechmere Viaduct now under construction between the Gilmore Bridge and Lechmere Station along Monsignor O’Brien Highway. The work is in support of the Green Line Extension (GLX) project. Setup operations will begin around 9 PM on Friday, July 10, and traffic detours will be in place by the early morning hours of Saturday, July 11. Construction activities such as crane work are scheduled from 7 AM to 10 PM on Saturday and from 7 AM to 7 PM on Sunday.
Traffic detours for motor vehicles, pedestrians, and bicyclists traveling through the area along Monsignor O’Brien Highway will be in place throughout the weekend. The purpose of the construction work is to place a series of prefabricated concrete pier caps atop the support columns for the new Lechmere viaduct. This construction method was chosen over casting the structures in place to save time on the project which is on schedule for completion in December of 2021. The GLX project will extend Green Line service from the new Lechmere Station along 2 new branches to Union Square in Somerville and to College Avenue/Tufts University in Medford.
Delivery of the pre-cast materials and preparations for the series crane lifts will take place between 10 PM and 7 AM on Friday and Saturday nights. Anticipated noise levels during the overnight periods are expected to be light to moderate. The materials will be set in place from 7 AM to 10 PM on Saturday and 7 AM to 7 PM on Sunday.
There is information online about weekend detour routes.