High Quality Content by WIKIPEDIA articles! The Red Line is a rapid transit line operated by the MBTA running roughly north-south through Boston, Massachusetts into neighboring communities. The line begins west of Boston, in Cambridge, Massachusetts at Alewife station, near the intersection of Alewife Brook Parkway and Route 2. The line passes through downtown Boston, with transfers to the Green Line at Park Street station, the Orange Line at Downtown Crossing, and the Silver Line at South Station. South of downtown, the line splits at JFK/UMass station, where one branch provides service to Braintree station and the other to Ashmont station. A connection to the Ashmont-Mattapan High Speed Line extends the reach of the Ashmont branch to Mattapan station.