Tremont Street Line (TR) Malden Extension (ME) Washington Street Line (WD) Charlestown Division (CD) Washington Street Tunnel (WST) Roxbury Division (RD) Forest Hills Extension (FHE) Beacon Hill Tunnel (BHT) Dorchester Street Line (D) East Boston Tunnel (EBT) Industrial processes and equipment Employees and offices Vehicles Allston Arlington Belmont Boston - Back Bay Boston - Beacon Hill Boston - Boston Common Boston - Downtown Boston - Haymarket Square Boston - North End Boston - North Station Boston - Scollay Square Boston - South End Boston - South Station Boston - Waterfront Boston - West End Brighton Brookline Cambridge Charlestown Chestnut Hill Dorchester Dorchester Avenue East Boston Everett Fellsway Huntington Avenue Jamaica Plain Malden Mattapan Medford Milton Roxbury Somerville South Boston Measured drawings of the Sanford-Covell House, Newport , R.I. 1870 Set of architectural drawings of the Lady Pepperell House, Kittery Point, Maine, 1923 Image of the Spencer House, Newport, R.I., 1926