Green Line D Track and Signal Replacement

The D Line used to be a Commuter Rail route, and much of the signal infrastructure was installed when it was converted to light rail in the 1950s. Those signals were still helping us run trains safely when the project began in 2018, but they were not as efficient as modern signal systems. When they indicated a problem, a crew member had to go out to the tracks to diagnose and fix it. This could cause long, frustrating delays in service.

We replaced the outdated signals with a more centralized digital system that’s easier to maintain and monitor. When there is a problem, our team will be able to diagnose and fix it more efficiently.

Railroad tracks can last many decades. To ensure your safety, engineers regularly measure the wear and tear on all the tracks in our system—that includes checking the rails, railroad ties, and ballast, which is the gravel between the rails that helps with support and drainage.

The tracks between Beaconsfield and Riverside were still safe for daily use, but our engineers decided it was time for all new tracks, ties, and ballast. Because this is such a big part of the Green Line, work was broken up into sections and done on nights and weekends when fewer people ride the Green Line.

Now that the new tracks have been installed, you’ll notice that Green Line trains can travel faster. They've allowed us to lift speed restrictions on what were particularly outdated sections of the route.

From west to east, work included:

• Riverside: Track and signals
• Woodland: Signals
• Waban: Track and signals
• Eliot: Signals
• Newton Highlands: Track and signals
• Newton Centre: Track and signals
• Chestnut Hill: Track and signals
• Reservoir: Track and signals
• Beaconsfield: Track

Shuttles replaced train service during many weeknights and weekends.

As part of accelerated work on the D Branch Track and Signal Replacement project, four nine-day, full-access closures were completed in summer 2020 and summer 2021. Free, accessible shuttle buses ran all day, every day during these closures.

We used several strategies to minimize noise disruptions for neighbors, including the following:

• Assembled track panels off-site
• Accessed work sites through the MBTA right of way
• Used self-adjusting backup alarms, silencers, or mufflers on equipment
• Limited truck and equipment idling
• Lined dumping bins, hoppers, and trucks with sound-deadening material
• Used noise blankets and shielding where possible

We monitored noise levels and responded to all noise complaints.