MBTA Completes Green Line D Branch Track and Signal Replacement Project

Today the MBTA announced the completion of the Green Line D Branch Track and Signal Replacement Project, enhancing safety, reliability, and resilience. This project began in June 2018 as part of Green Line Transformation program with the goal of improving track conditions and signal efficiency while also reducing the overall risk of maintenance delays and need for repairs. Since June 2018, 25,000 feet of track on the D Branch have been replaced between Riverside and Beaconsfield Stations as well as 6.5 miles of signals.

This project aimed to improve the condition of the D Branch. Prior to the Track and Signal Replacement Project, outdated signals were responsible for 120 signaling incidents on the D Branch during 2017 and 2018. These incidents caused extensive delays and reduced headway adherence. Replacing signals with modern technology increases on-time performance by reducing signal problems and improving the rider experience. The new signals will be much easier to monitor and fix, and will provide quicker and more reliable transportation across the D Branch. Replacement of the tracks eliminates over 2,000 feet of slow zones, which provides a savings of two-and-a-half minutes of travel time in each direction.

The D Branch was once a Commuter Rail route, and when converted to a light rail trolley system in the 1950s, the MBTA installed much of the signal infrastructure that was still in use when this project began. When there was a problem experienced within this old system, work crews were required to travel directly on to the tracks to diagnose and fix the issue. With the more centralized, digital system now currently complete on the D Branch, the signal system is easier to maintain and monitor. The MBTA’s work crews will now be able to easily diagnose and fix potential issues faster.

Before construction began in 2018, the average age of the tracks on the D Branch was over 30 years old. These tracks were replaced, bringing riders faster travel times, increased safety, better ride quality, and a lower risk of service disruptions from track issues.

Over three years, construction used weeknights and weekends to perform track and signal upgrades with shuttle buses providing alternative service. Early in the project, maintaining late-night service for baseball fans at Fenway Park significantly limited the duration of time that crews could work on the D Branch. The preliminary phases of the COVID-19 pandemic presented further complications to safely complete the work while providing the robust service needed for first responders.

-via Press Release

This article was posted on: December 10, 2021