The Ashmont-Mattapan High Speed Line (or Mattapan-Ashmont Line, or just the M Line) is considered part of the MBTA's Red Line, even though it uses different equipment (trolleys) and passengers have to change at Ashmont Station . It is the only MBTA line to run through a cemetery.

Rolling Stock

The rolling stock of the Mattapan-Ashmont Line consists of refurbished, historic PCC streetcars that formerly ran on the Green Line.

Stations

• Mattapan
• Capen St.
• Valley Rd.
• Central Ave.
• Milton
• Butler
• Cedar Grove
• Ashmont (transfer to Dorchester branch of the Red Line)