 The main portion (between Alewife and Somerville Junction) had been constructed by the Boston and Lowell Railroad to connect its main line to the Lexington and Arlington Railroad; the remainder west of Alewife forms what is now known as the Fitchburg Cutoff Path.Except for deviation in the first quarter mile east of Alewife, the right-of-way between Alewife and Davis Square became the underground Red Line extension in the 1980s.Portions of the surface between Alewife and the Lowell Line (including over the Red Line) have been turned into the Cambridge Linear Park and the Somerville Community Path, and the remainder is slated to become an eastward extension of the Community Path.