Century-Old Infrastructure Gets Modern Upgrade
The wooden troughs that have lined the ceilings of Boston's Green Line tunnels since their construction in the late 1890s have finally been retired. These components, which served as crucial barriers between electrified train wires and tunnel ceilings, have been replaced with modern metal versions after nearly 130 years of service.
According to MBTA officials, years of water damage had degraded sections of the wooden troughs, and the aging wood presented a fire risk. Federal and state authorities determined last year that replacement was necessary for safety reasons.
"They were 'degraded,' but still safe and functioning," MBTA Chief Operating Officer Ryan Coholan stated during a public meeting. "Still, 'it's a 130-year-old piece of wood underneath Boston Common... The day it decides to bite us, it's going to significantly impact our service.'"
Major Shutdown Required
The replacement project required shutting down all four Green Line branches across Downtown Boston from December 8 to December 22, 2025. This allowed maintenance crews uninterrupted access to complete the extensive work.
Working continuously for two weeks, crews replaced approximately 13,000 feet of wooden trough with modern equivalents that Coholan said will "outlast all of us."
Massachusetts Transportation Secretary and MBTA General Manager Phillip Eng explained last month that a two-week closure represented the least disruptive scheduling option for this essential work. The T has adopted a "bite the bullet" approach to projects requiring significant operational disruption, completing as much work as possible during single extended closures.
Additional Improvements Completed
During the shutdown, maintenance crews took advantage of the access to complete other critical projects. These included installing the new Green Line Train Protection System, a network of transponders designed to warn train operators about potential collisions and speeding violations.
At Boylston station beneath Boston Common, crews also installed new steel beams to support tunnel ceilings in areas where water damage had weakened existing structural components.
Public Impact and Response
The shutdown affected approximately 50,000 daily Green Line riders, according to November data from TransitMatters, a public transportation advocacy organization. During the closure, the MBTA provided free shuttle buses as alternative transportation, while many riders shifted to the Orange Line, commuter rail, or public buses.
"This was really, really important," Coholan emphasized. "We appreciate the patience of the public. We know this is impactful."
Eng noted last month that the wooden troughs had remained in place for five generations due to delayed investment in their replacement. He described the replacement as "vital" and stated, "It's a result of the need to take care of things more timely, and we're committed to doing that."
The project was scheduled for completion on Monday, December 22, with the Green Line reopening on Tuesday morning, December 23, 2025.
