MBTA Green Line service at Union Square reopens ahead of schedule with all slow zones lifted

The MBTA resumed service to Union Square station on the Green Line Wednesday morning following the completion of construction, two days ahead of schedule.

Green Line service between Lechmere and Union Square had been closed since Sept. 20 to allow for Massachusetts Department of Transportation construction on the Squires Bridge in Somerville. The bridge carries Route 28/McGrath Highway over the Union branch of the Green Line and the Fitchburg line of the commuter rail. Neither Route 28 or the Fitchburg line were impacted by construction.

In a press release, MBTA General Manager and CEO Phillip Eng thanked riders for their patience during the closure.

Transportation officials had initially released a plan in June to close the Green Line extension for 42 days to work on the Squires Bridge from July through August. Officials then changed the timeline of construction plan so that it would not coincide with the summer Sumner Tunnel closure and would take 25 days instead.

“We’re proud to have completed repairs of the Squires Bridge ahead of schedule and to have resumed Green Line train service in this area as quickly and safely as possible,” said Acting Transportation Secretary and CEO Monica Tibbits-Nutt in a statement.

Along with the reopening, the transit agency announced all slow zones were lifted on the Union Square and the Medford/Tufts Station branches.

The new Green Line Extension fully opened in December 2022 but, according to reporting from the Boston Globe, faced speed restrictions in June 2023 once the MBTA learned the tracks had become too narrow to allow trains to go at full speed. The issue was fixed in June but came up again in September, leading to additional speed restrictions.

In late September, MBTA spokesperson Joe Pesaturo told WBUR the agency was still working to determine the root cause of the narrowing.

The MBTA's speed restriction tracking dashboard shows 11 restrictions were removed from the Green Line between Oct. 9 and 10.

With reporting from WBUR's newsroom and Nik DeCosta-Klipa