Derailed: The History of the Green Line Extension Project (GLX)
BY DANIEL JIANG '25
A year ago, on December 12th, 2022, the MBTA’s Green Line Extension Project (abb. GLX) had a ribbon-cutting ceremony and was officially declared open for service for the public. The project extended the D and E branches of the Green line to Union Square in Somerville and to Tufts University in Medford. It was a major success to finally have the project completed. Yet the joy did not last for long, as in October 2023 the MBTA broke news to the public that the entirety of the extension had to be shut down for a prolonged 7-weeks to fix inaccurate track gauges. This deadline was dragged on further when the proposed deadline to complete the work was not met. Since that date the GLX has re-opened, but what exactly happened during the construction process, and why did it take more than a decade to complete such a small extension?
The Massachusetts Bay Transportation Authority (abb. MBTA) is a rapid-transit network originating in Boston proper. It contains a plethora of commuter rail lines, bus and intercity-bus lines, three heavy-rail lines and one light-rail line. The light rail line, colored a bright green, is the MBTA’s oldest line, and subsequently the first ever instance of a subway in the entirety of North America. Pre-pandemic, the line saw an average of 137,000 riders a day. It serves multiple communities outside of Boston, such as Cambridge and Newton, and is a vital part of how Bostonians get around.
Talks about creating or expanding a grade-separated, rapid-transit network from Boston’s northern end (where North Station stands today) were plentiful as early as the 1920s, and the idea was kept alive all the way until the 1980’s, but was really brought to attention when Boston decided to relocate the I-93 freeway. This project to tunnel the freeway underneath the city would eventually become known as the “Big Dig”.
The Big Dig emitted tons of pollution from construction. To mitigate the effects of the pollution a transit project was drafted up. This project had a large scope: creating an “Urban Ring” of rapid-bus transit around Boston, renovations on certain lines, and most importantly, an extension. The GLX was born right around this time. Then-Governor Michael Dukakis promoted the GLX project, promising Bostonians that it would be complete by 2011 to comply with the Clean Air Act.
Woefully so, that wasn’t the case.
After Dukakis, the next four Massachusetts Governors weren’t too interested with public transportation, and so the project rotted on a bookshelf for the next couple of years as money was drained to improve automobile infrastructure across the state. Mitt Romney took office in 2003, and he decided to re-open the GLX project and so GLX formed itself over the next couple of years. In the Federal Transit Administration’s 2013 “Annual Report on Funding Recommendations: Fiscal Year 2014 Capital Investment Program”, the estimated cost was around $1.1158 billion dollars. Within three years, the GLX project had inflated to an extra billion dollars.
To complete the project the MBTA bidded out the project to private contractors in 2013. It hired a private team that consisted of a construction manager and a general contractor, which was assembled under a joint collaboration between the J.F White Contracting Co., the Kiewit Corporation, and Skanska Construction. The MBTA also contracted a program manager and construction manager with forces from the HDR Construction Company and the Gilbane Building Company.
The internal cost estimates between the groups contracted by the MBTA started to drift further apart during construction. The contracts began to outpace the project’s budget and was beginning to eat into the project’s contingency fund. In August of 2015, when negotiating the sixth GLX contract with the construction groups, their estimates for 100% completion came in at almost double the construction cost (approx. $3 billion to complete the project). Instead of agreeing with the group, the MBTA decided to sack them and the newly-established Financial Management and Control Board (abb. FMCB) announced that the project, if it cannot be reduced in price, will be suspended indefinitely.
And so the project froze for a while, during which the MBTA decided to completely re-analyze the project scope. The team concluded that costs can be reduced if the scope of the stations, retaining walls, bridges and the vehicle maintenance facility was reduced. In between all of this, the MBTA hired the GLX Constructors, a joint venture by the Fluor Construction Corp., to complete the building aspect of the GLX project. This team would complete the project to the end, enduring past the COVID-19 pandemic that threw progress off.
Fast-forward to the present, and another issue has dropped upon this already-delayed project, and that is the tracks themselves. It’s unclear whether or not there was miscommunication between project designs or out of negligence, but the track gauge was built at mere fractions of an inch narrower than the standard gauge the rest of the MBTA’s Green line runs on (4ft. 8⅛in.).
What infuriates the public the most is that the issue appeared during an inspection in 2021, yet this problem was deemed insignificant and failed to report in reports. Should it have been noted sooner, then maybe the entire shutdown could have been avoided.
This incident adds another stain to an already-stained timeline of the recent flaws of the MBTA post-pandemic. Some notable incidents include a plethora of train collisions and derailments, the horrific death of a man falling through rusted staircases and another death of a woman at a malfunctioning railroad crossing, a runaway Red line train, collapse of overhead wires at Park Street station, and minor derailments throughout all modes.