Green Line extension will shut down — again — in December for repairs

Green Line riders are in for a rough December as the MBTA plans to shut down large sections of the subway line for repairs — again — including the brand new Green Line extension to Somerville and Medford.

On the $2.3 billion Green Line extension that fully opened less than a year ago, crews will aim to reposition most of the new track that the T says was constructed incorrectly before the newest part of the subway system debuted. Riders will again go without Green Line service between North Station and Union Square and Medford/Tufts stations from 8:45 p.m. through the end of service daily from Nov. 27 through Dec. 10, the T said.

The T shut down the same area every weekend in June.

The repairs come after the T slowed train service on the Green Line extension to a walking pace over more than a mile of track in September to prevent derailments in areas the agency said were too narrow to operate trains safely at full speed. Further investigation showed that at least 80 percent of the Medford branch and at least 50 percent of the Union Square branch track is more narrow than what the project contract called for, the agency said, and will have to be redone.

Trains on the extension went back to full speed on Oct. 11.

Later this month and next month, the T is planning to shut down other parts of the Green Line, where the agency has previously suspended service for station work and track replacement.

From Nov. 27, through Dec. 5 the Green Line will be closed on the B branch between North Station and Babcock Street, on the E branch between North Station and Heath Street, and on the C and D branches between North Station and Kenmore. On Dec. 4 and Dec. 5, the Green Line will also be closed between North Station and Lechmere.

The Green Line’s D branch between Kenmore and Riverside will be closed from Dec. 11 through Dec. 20.

The upcoming service suspension along the B branch covers some of the territory where service was disrupted for a time in 2021 while the MBTA consolidated four stops into two near the Boston University campus.

The $29.3 million project was completed in November 2021 and included track work and the construction of two new, fully-accessible stations at Babcock and Armory streets.

During the upcoming repairs on the B branch, no track work is scheduled to take place west of Blandford Street, but service will be suspended further west to Babcock Street because that’s the closest spot to Boston where trolleys can turn around to return to Boston College, said Joe Pesaturo, a T spokesperson.

The upcoming suspension of service between North Station and Lechmere Station covers the same section that the T closed for nearly two years from May 2020 to March 2022 as part of the $87.4 million Lechmere Viaduct rehabilitation project that “renewed more than 3,500 feet of track,” according to the T’s website. A slow zone has been in place on the new track since it reopened.

From Nov. 27 through Dec. 5, the Green Line will be closed between North Station and Government Center and the Orange Line will bypass Haymarket to accommodate demolition work on the Government Center garage.

On Dec. 6 to Dec. 16, the Green Line and Orange Line will bypass Haymarket for the same demolition work.

Earlier this month, MBTA general manager Phillip Eng announced subway closures on every line for the next 14 months that he hopes will allow for enough repairs to lift all slow zones by the end of next year. Currently, the agency is forcing trains to slow down over track defects on 23 percent of the agency’s subway system, according to its speed restriction dashboard.

On Thursday, the T said it needs at least $2 billion to repair or replace 89 percent of its subway track because that track is past its useful life.