Watch Online Free on Watchseries. The Ashmont-Mattapan High Speed Line operates 2.6 miles of track from Ashmont Station to Mattapan Station just south of Boston. We capture this neat little commuter operation in the state of Massachusetts. They operate with all PCC trolley cars! This operation offers a vital link to commuters to get to Boston easily from the suburbs of Boston! It is a landlocked line that connects with the Red Line at Ashmont Station! Filmed in 2022 & 2023 at 7 of the 8 stations.