[1] Horsecar service on the Beacon Street line began between Coolidge Corner and downtown Boston on June 1, 1888.

[2]: 54  Electrified service began between Allston and downtown Boston via Coolidge Corner on January 3, 1889.

[2]: 48  Service was extended west from Coolidge Corner to Reservoir on January 12, and from Allston to Oak Square the next day.

[7][8] A 1911-built electrical substation designed by Peabody and Stearns is located in Coolidge Corner on Webster Street.

Coolidge Corner and Washington Square were originally to have one mini-high platform apiece as well; however, portable lifts were added at the stations instead.