MBTA Continues to Successfully Advance Green Line Modernization Investments, Makes Significant Improvements in Green Line Reliability

The MBTA today announced the successful advancement of work on the Green Line, including critical work to replace and upgrade the 120-year-old signal system within the central tunnel and much more.

"The latest phase of work to replace our 120+-year-old signal system within the central Green Line tunnel is critical to building the modernized transit system that our riders deserve and can count on. Know that we maximized productivity by continuing to upgrade tracks, stations, and other essential components during the same track outage. It is vital that we build upon the momentum of previous phases of work, bringing us another step closer to ensuring we continue to deliver improved service today and in the future," said Interim Secretary of Transportation and MBTA General Manager and CEO Phillip Eng. "The new signals will provide the operational flexibility that is necessary to run a world-class system that Boston deserves, driving economic vitality and quality of life for all that we serve. This work enables us to deliver for our riders the new fleet of state-of-the-art Green Line Type 10 cars next year. Thank you to the public for their patience and allowing us to perform this vital work that has been so long-deferred. Under the Healey-Driscoll Administration and with the support of the Legislature, we are investing in the system which is an investment in the future of Massachusetts and the businesses and communities that we serve."

Green Line Work Accomplished

This important work within the Green Line central tunnel was accomplished during nine consecutive days of 24/7 access to portions of the Green Line that ended yesterday, which allowed the MBTA to expedite the long-awaited upgrades in the most cost-efficient manner possible.

At over 100 years old, the MBTA's Green Line legacy signal system is as old as the tunnel itself - the old signals currently in use are the same signals that were used when the first electric trolleys in North America were put into service in the late 1800s. This signal system is ready to be replaced with the upgraded, modern technology of today.

The age of the MBTA's signals and the scale of replacing the entire system within the central tunnel makes the project significant, and previous administrations had deferred this work due to its challenging complexities. With a commitment to accomplishing long-awaited upgrades that riders deserve, the MBTA is no longer deferring these critical investments. It was determined that the best way to accomplish the Green Line's signal modernization on an accelerated timeline is the phased approach: several diversions in service in which the MBTA could maximize each outage by performing as much other piggybacking work as possible.

During these nine days of unencumbered access to the Green Line, work crews have continued to make progress on a variety of complicated activities in the tunnel, including extensive signal cable and infrastructure installations, messenger cable work, and complex work at electrical conduit crossings. Over 20 miles of new signaling cable were routed through newly installed signal equipment during this most recent service outage, totaling 40 miles of cable installed so far - the MBTA plans to route 72 miles of new cable in total. Approximately 75% of junction boxes, signal heads, and termination cases have been installed within the Green Line track area, including signal heads that will be activated during the commissioning and verification process at the end of the project. More than 85% of the project's 129 new signal junction boxes have been installed throughout the tunnel and near station platforms, replacing boxes dating back to the 1940s.

This construction work is part of the MBTA's phased approach to accomplishing signal upgrades in three major areas at Copley, Park Street, and Government Center, and builds upon previous work that has taken place this year. Within the Copley area, infrastructure installation and routing of the signal cable are 100% complete, and the installation of signal equipment within the track area is 95% complete. At Park Street, infrastructure installation is 98% complete, the installation of signal equipment within the track area and routing of signal cable are each 60% complete, and a new signal communications room serving the Park Street signal system is 25% complete with wiring and equipment installation underway. At Government Center, infrastructure installation is 95% complete, and the installation of signal equipment within the track area is 70% complete.

Following this work to install all of the signaling infrastructure, the testing and commissioning phase will begin, which is the thorough and exacting process of cutting over to the new system and verifying that the new system is functioning properly.

When the testing and commissioning phase is complete and the Green Line has fully transitioned to the new signals, the new system will provide the MBTA Operations team with improved train detection, better train congestion management, and more consistent train spacing, which provide the foundation for improved service frequency. These operational upgrades also mean more reliable service for riders with fewer unplanned disruptions and emergency repairs caused by the older, aging signal system.

Compatible with the upcoming fleet of new Type 10 Green Line cars, these signal upgrades also help prepare the MBTA for future generations of riders.

The unencumbered access to the Green Line track area allows the MBTA to accomplish many other piggybacking projects. This work includes the following:

• Maintenance of Way crews are continuing the critical station upgrade work at Symphony as well as replacing ties and ballast in the track area of the station.
  
• Power maintenance crews inspected and repaired power cables and underground access boxes, and clean or replace switchboxes.
  
• The Vehicle Engineering team continued work on the critical Green Line Train Protection System.
  
• With the new fleet of Type 10 cars soon arriving, crews performed modifications to curbs and platform edges between Boylston and Haymarket as well as the "Brattle Loop" track area near Government Center to provide clearance for the new larger vehicles.
  
• Crews upgraded radio infrastructure throughout the diversion area and began the installation of new radio system cable within the E Branch tunnel area.
  
• Crews relocated the electric overheard catenary wires, which power Green Line cars, at complicated sharp curve area in order to accommodate both existing vehicles and the new Type 10 fleet.
  
• At Park Street, workers performed over 400 feet of full-depth reconstruction of the eastbound track and rebuild the pedestrian crossing.
  
• Station brightening, critical maintenance, and repair work took place at all stations between Kenmore Station and North Station, including painting, assorted repairs, HVAC maintenance, and inspections.
  
• Through close coordination with utility partners, Verizon also installed a manhole casting near Amory Street.

Significance of Multi-Day Outages

The MBTA is reminding riders that service outages such as these are a critical and necessary part of maintaining the infrastructure improvements that took place as part of the 2024 Track Improvement Program while also making further system upgrades and modernizing the MBTA's infrastructure. This work cannot be performed during the overnight hours when the MBTA does not operate, and would be extremely inefficient and costly if planned during single weekend outages.

Closing a section of the transit system for multiple days is the most efficient way to perform the MBTA's routine maintenance, revitalization efforts, inspections, and upgrade work, and combines the efforts of multiple contractors and the MBTA workforce around the clock 24/7 to maximize productivity. This work is necessary and continuous to maintain the reliable service riders count on.