premise: Tremont Street Subway is incapable of serving any stations.
hypothesis: Tremont Street Subway . It now forms the central part of the Green Line , connecting Boylston Street to Park Street and Government Center stations . The tunnel originally served five closely spaced stations : Boylston , Park Street , Scollay Square , Adams Square , and Haymarket , with branches to the Public Garden Portal and Pleasant Street Incline south of Boylston . Park Street , Scollay Square , and Haymarket stations were altered over the next two decades as transfers were added to the Cambridge-Dorchester Subway , East Boston Tunnel , and Main Line Elevated ( now part of the Red , Blue , and Orange Lines , respectively ) .