The Orange Line at one time had elevated railway lines on its north side (Everett Terminal), and on its south side (Forest Hills Terminal). The Everett line was demolished in 1975, and the Forest Hills "L" was torn down in 1987.
On March 6, 1913, a southbound Forest Hills "L" car jumped a switch at the Guild Street train yard, just south of Dudley Street Station. The forward car of the train then struck empty coaches with significant impact, and came to rest on the ties in a switching area of the elevated structure. The passengers were thrown from their seats, but thankfully no one was seriously hurt. The following was reported in the March 7th issue of the Boston Globe:
"The Forest Hills train left the Dudley-st Terminal about 8:52 [p.m.]. Preceding it by a small margin was an empty train, which had been run into the Guild-st yard. Following closely behind, the motorman of the passenger train did not notice the open switch as he passed the tower house, and before he was aware of the mistake the trucks of the forward car of the four-car train had taken the switch and had rounded the curve leading into the yard. Quickly shutting off the power and applying the brakes, he did everything within his power to avert the collision.
Notwithstanding the fact that the momentum of the passenger train had been greatly decreased by the application of the emergency brakes, the forward car bumped into the rear end of empty train which was standing still. The sound of the breaking glass in the vestibule of the first car of the passenger train created consternation, but quiet was quickly restored."
The accident occurred 53 feet above street-level, and the shattered glass fell onto the street below. The rear wheels of the empty coach were forced off the track, and came to rest near the third rail. Thankfully, the operator had reacted quickly in the emergency, as the accident could have been much worse. The rear 3 cars of the passenger train were detached and brought back to the main line. The train then continued on to the Forest Hills destination.
The photo above is from 1975, and was taken from the last car of a four car train heading to Forest Hills. This view is very near where the last car of the passenger train would have been in the 1913 accident.