[4] Passengers must transfer at Ashmont to access the rest of the Red Line, which uses heavy rail metro rolling stock.

Unlike most heritage streetcar lines, it is an integral part of the modern MBTA transit system rather than a tourist attraction.

[5] Most Mattapan passenger service switched to use the new branch east of Milton, as it ran through dense urban neighborhoods rather than swamps.

[7]: 7  Under that plan, a bidirectional rapid transit loop would run south from Andrew along the Old Colony main line, take over the Shawmut Branch and Milton branch to Mattapan, cut over to the Midland Division on a tunnel, and return to Andrew via the Midland Division right-of-way and another tunnel segment.

[2][8] In January 1981, the MBTA proposed to close the Mattapan Line at all times beginning that March due to severe budget issues.

[9] The closure was cancelled, though the Mattapan line and the Ashmont branch were closed from June 20, 1981, to January 16, 1982, for track replacement and tunnel repairs.

A new elevated loop was built at Ashmont – part of a major reconstruction of the station – and the aging canopy at Mattapan was replaced.

Rehabilitation of the existing fleet is happening at the same time, to extend trolley life a few more years until LRVs arrive.

[1] The line begins and ends within the city of Boston, but most of the southern half of its route is in the northern part of the neighboring town of Milton.

The first two trolleys had stopped to avoid a police car, which had become stuck on the tracks while the officer was investigating teenagers drinking near the line.

[17] Using funding from the American Recovery and Reinvestment Act of 2009, the MBTA conducted a pilot test of technology similar to a collision avoidance system in an automobile, using radar and increasingly fast beeping to warn train operators of obstacles ahead.

Other T lines simply run regular trains to clear the tracks of snow, but the PCC cars' traction motors would short out if they were used for that purpose.

[24] During the latter rebuild, the cars were repainted from their former Green Line paint scheme to a brighter orange and cream design, similar to their original coloring.

The plan also allocated $5 million for "PCC Car Replacement-Alternative Service" which was to be used for future funding should an alternate form of transportation be decided upon.

[27] In 2017, MBTA began a $7.9 million project to overhaul the trolleys and update the propulsion systems, but further problems such as fluctuations in power damaged the four operating trains in early 2018.

In January 2019, eventual conversion for use of new light rail vehicles (or Type 9 LRVs transferred from the Green Line) was reported to be the most viable option.