page_title: Silver Line (MBTA)
section_title: Phase III plans
hierarchical_section_title: Silver Line (MBTA) / History / Phase III plans
context_page_description: The Silver Line is a system of bus routes in Boston and Chelsea, Massachusetts, operated by the Massachusetts Bay Transportation Authority (MBTA). It is operated as part of the MBTA bus system, but branded as bus rapid transit as part of the MBTA subway system. Six routes are operated as part of two disconnected corridors. As of 2019, weekday ridership on the Silver Line was 39,000.
  The four Waterfront routes operate out of an underground terminal at South Station and run through the South Boston Piers Transitway – a dedicated bus tunnel through the Seaport District with stations at Courthouse and World Trade Center. At Silver Line Way, they fan out on the surface: the SL1 to Logan International Airport, the SL2 to Design Center, and the SL3 to Chelsea via East Boston. An additional short turn route, SLW, runs only at peak hours between South Station and Silver Line Way. The Waterfront routes use articulated dual-mode buses that operate as electric trolleybuses in the Transitway and conventional diesel buses on the surface. Two routes operate on Washington Street between Nubian station and Downtown Boston.
context_section_description: The Boylston extension, as planned in 1993, would have run west from South Station under Essex Street, Avenue de Lafayette, and Avery Street. The Chinatown platform would have been under Hayward Place east of Washington Street, and the Boylston platform under the existing Green Line station, with a turnaround loop under Boylston Street and the Central Burying Ground. The 1999 decision to combine the Waterfront and Washington Street projects as the Silver Line resulted in the addition of a southern segment, likely using the same abandoned streetcar tunnel as had been proposed a decade before. A new underground station would have been built under Tremont Street, connecting to the existing New England Medical Center (NEMC) station, with a portal to Washington Street just north of Oak Street. In April 2000, the MBTA adjusted the alignment to use Boylston Street instead of Avenue de Lafayette and Avery Street, with side platforms at the stations. The new alignment would conflict less with development, provide a straighter route, avoid the need for a pedestrian crossing and a lengthy pedestrian tunnel at Chinatown, and move the Boylston loop away from the Burying Ground.
  In January 2002, the MBTA began seeking federal funding for 60% of the project cost. The FTA approved the project for further planning that July. The Boston Regional Metropolitan Planning Organization rated the project as "high priority" in its May 2003 Program for Mass Transportation, citing its high estimated ridership, low operating cost and service to environmental justice neighborhoods. In 2003, the preferred portal location was moved slightly north to avoid the need to demolish the YMCA building, and the NEMC station was removed. A proposal to consolidate the Chinatown and Boylsyon stations was rejected due to steep grades required and lack of cost savings, and a proposal to eliminate the loop was rejected because of the need to short turn most buses at Boylston. Further changes in 2003–04 were caused by the need to add a second platform at Boylston due to high expected ridership, and to reduce impacts to the historic Boston Common from the loop. One alternative placed the station and loop under Tremont Street south of Boylston Street; the other enlarged them under the Common.
  Continued concerns about the Common, concerns from Bay Village residents about impacts to Eliot Norton Park, and desires to add Back Bay service resulted in further changes in 2004–05. The platforms at Boylston were to be aligned east–west under Boylston Street west of Tremont Street, with the loop further to the west at Charles Street. New portal alignments were considered, including one on Columbus Avenue to the southwest. Capital cost was originally estimated at $768–812 million depending on the portal location; completion was moved from 2010 to 2013. Daily ridership for the completed Silver Line system was estimated to reach 160,000 by 2025. In August 2005, the MBTA put the Phase III project "on hold" in order to build community consensus on a locally preferred routing.
  In February 2006, State Transportation Secretary John Cogliano proposed a $94 million plan that would eliminate most of the tunneling and cost of the original proposal while still connecting the two phases of the service. Under Cogliano's plan, the Silver Line would run on the surface via Kneeland Street and Surface Road to a new tunnel portal on Essex Street near South Station. A fare-controlled shelter would be added at Downtown Crossing for routes still terminating there. The plan also included expansion of surface Silver Line service, with a new branch running from Copley Square into the Essex Street portal to provide a one-seat ride from the Back Bay area. The southern branch would be extended from Dudley to the Red Line stations at Mattapan via Blue Hill Avenue (replacing route 28) and Ashmont via Washington Street (replacing route 23) The plan was popular with Bay Village residents who had been worried about the full-length tunnel, but attracted criticism because it would not substantially speed travel ti
caption: Silver Line Phase III alternatives, showing the original 4 alignments plus the Charles Street Modified (CSM) alignment. The preferred route at the time of the project's cancellation was the CSM alignment (pink) feeding into the core tunnel (green).