Work is needed on the MBTA tunnels under the streets of downtown Boston

Summer inspections of the MBTA tunnels revealed that work is needed on the subway structures that run under Boston’s downtown streets, MBTA General Manager Philip Ng said during a presentation Thursday on the agency’s reform plans for next year. Reviews in August identified “the structural work we need to do on the tunnels above that support the streets, and the street level above our Green Line,” Ng told members of the MBTA Board of Directors’ Safety, Health and Environment Subcommittee. The planned closure of the Green Line from North Station through Kenmore to Heath and Babcock to address tunnel issues is scheduled to begin on Nov. 27, he said. The Green Line tunnels extend under several major thoroughfares, including parts of Boylston Street, Tremont Street, Beacon Street and Huntington Street. “This structural work is critical. It’s critical to safety, and we want to make sure we address this before winter,” the engineer said. During the closure, which will last through Dec. 5, Ng said crews will also address the 10 speed restrictions related to track issues and catenary issues related to overhead wires that Ng said were recently identified. >> America’s first subway: Abandoned interior under Boston The work needed inside the Green Line tunnels is one of a few projects the MBTA plans to tackle before the end of the year and part of a larger work plan that extends through 2024. The general manager said the plans are significant SAM Engineers Cho introduced Thursday will address all current speed restrictions that are causing trains to move at a slower pace than usual. The engineer said there are currently 191 speed restrictions, of which 39 will be lifted by the end of this year and the rest by the end of 2024. It is expected that a total of 188 days of phased closures will be needed for these reforms over the next year. Under the plans, the restrictions will be addressed through a series of additional closures and diversions across the MBTA system. The duration of the closures will range from a few days to a few weeks. According to the MBTA’s Speed ​​Restrictions Dashboard, restrictions across the Blue, Orange, Red and Green lines make up 23% of the agency’s routes. Restrictions have been imposed due to track erosion or other identified issues. As each defect is validated and corrected, the block constraint length is reduced until the velocity constraint is completely removed. Last month, the MBTA lifted speed restrictions on the Green Line following construction on the Squires Bridge in Somerville. It was completed ahead of schedule. The speed restrictions, which caused trains to slow down at up to 3mph on some sections of track, were put in place after a survey found the space between the tracks had narrowed slightly. Also in October, the Red Line’s Ashmont Branch and the entire Mattapan Line were closed to address dozens of speed restrictions that were slowing trains.