It will take perhaps two weeks to fix a track concern causing trains to crawl at pedestrian speeds along the Green Line Extension.
MBTA General Manager Phil Eng, during a meeting of the transportation agency’s board of directors Tuesday morning, said a discrepancy in the width of Green Line tracks could be fixed as soon as mid-November.
“It’s not months, it’s not years to address this,” Eng told the Board.
Last week, Eng revealed that previous MBTA officials discovered but did not publicly disclose a problem with the line’s prefabricated railroad ties, leading to tracks that were out of design specifications and not to national rail standards.
“We did a deeper dive into the project to understand why a project that was recently opened, new construction, resulted in conditions that were unacceptable,” he said. “What we identified was that we had tight gauges across significant portions of the GLX project.”
According to Eng, about half of the track along the Union branch of the Green Line Extension and 80% of the Medford-Tufts branch are outside of the industry rail gauge standard — sometimes called the Stephenson gauge — of 56-and-a-half inches. Parts of the track are between an eighth and a three-eighths of an inch too narrow, Eng said, despite the contract calling for no more than a sixteenth of an inch tolerance.
“That does not mean it was unsafe to run trains,” the GM said.
Under a proposed corrective action plan offered by the construction conglomerate that installed the tracks, GLX Constructors, work could begin as soon as next month and would occur overnight, from 9 p.m. to 5 a.m.
Eng said the company’s proposal, which MBTA officials are still reviewing, calls for “10 to 14 nights of work” starting on November 1 to “address and regauge all of the track that needs to be done along both branches.”
To fix the problem, Eng told the board, the pre-installed plates connecting the metal train track to the wooden rail ties will need to be unbolted, the bolt holes filled and re-drilled, and the plates and track reconnected. The procedure is not entirely uncommon in the rail industry, Eng said, and his staff is focused on making sure the solution won’t result in future frustrations.
GLX Constructors — an entity made up of Fluor Enterprises Inc., The Middlesex Corporation, Herzog Contracting Corp. and Balfour Beatty Infrastructure, Inc. — will have to foot the bill for fixing the track problem, according to the GM.
The roughly $2.3 billion Green Line Extension project was completed at the end of last year, with a new branch that starts in Medford at the Tufts/College Avenue station and adds four stops in Somerville. A smaller branch opened in March 2022, adding service at the Union Square station in Somerville.