The Red Line is an MBTA rapid transit line in the Boston, Massachusetts area. Its northwestern terminal is at Alewife near Fresh Pond Parkway and Route 2 in West Cambridge, from which it passes through downtown, with transfers to the Green Line at Park Street and the Orange Line at Downtown Crossing. South of downtown it splits into two branches; one branch runs to Braintree and the other to Ashmont, with the Ashmont-Mattapan High Speed Line continuing to Mattapan.