TheBoylston Street subway is alight rail tunnel which lies primarily underBoylston Street inBoston, Massachusetts. In operation since 1914, it now carries all four branches of theMBTAGreen Line fromKenmore Square under theBack Bay into downtown Boston, where it joins with the olderTremont Street subway. The tunnel originally ended just east of Kenmore Square; it was extended under the square to new portals atBlandford Street andSaint Mary's Street in 1932.[1]: 44
The eastern end of the tunnel is at theTremont Street subway, just west ofBoylston station near the intersection of Boylston Street andTremont Street next toBoston Common. It then runs westward under Boylston Street;Arlington station is located at Arlington Street, andCopley station is at Dartmouth Street inCopley Square. TheHuntington Avenue subway branches off to the south just to the west of Copley. The main line continues west under Boylston Street; at Hereford Street, it curves northward intoHynes Convention Center station atMassachusetts Avenue, then runs west underNewbury Street and theMuddy River and intoKenmore station atKenmore Square.[1]: 44
The depth of the tunnel varies based on street considerations and other geography. At Arlington, Hynes Convention Center, and Kenmore, the tunnel is substantially below street level, and the stations have below-ground fare mezzanines offering access to both platforms; at Copley, the tunnel is shallower, and the fare gates are at platform level, with a free crossover to reverse direction not possible. The deepest section of the tunnel is under the Muddy River, in theFenway neighborhood of Boston.[2]
Media related toBoylston Street Subway at Wikimedia Commons