High Quality Content by WIKIPEDIA articles! Porter is a station on the MBTA rapid transit Red Line and the commuter rail Fitchburg Line, at Porter Square in Cambridge, Massachusetts. It is at the intersection of Massachusetts Avenue and Somerville Avenue and serves northern Cambridge and portions of Somerville. The modern station was designed by Cambridge Seven Associates and opened on December 8, 1984. At 105 feet below ground, the subway section is the deepest station on the MBTA system. Porter is 14 minutes from Park Street on the Red Line.