The Boston City Archives has posted some photos of the aftermath of a crash on July 22, 1928 when a four-car elevated train crashed on a sharp curve at Beach Street and Harrison Avenue, killing two and injuring several others.
According to an Associated Press account from the time, the train's speed going into the curve just before the station was estimated at 40 m.p.h., far faster than it should have been going there:
It was scarcely a third of the way around when the trucks of the leading car left the rails and tore zig-zag fashion across the other track to crash into the abandoned Beach Street station.
The second car in which the two men who were killed were riding hurtled its nose into the side of the leading car and then jumped back and half-way across the flat roof of a building at the southerly corner of Beach street and Harrison avenue, carrying away the stone facing of the structure, crushing the walls and dropping its heavy trucks through the trestle. The two rear cars left the tracks but remained upright.
The accident occurred in a heavy rain. As the cars piled across the third rails, a great blue flash was visible for blocks around and the sound, heard clearly in the Lagrange street police station, brought a detail of men to the scene almost before the train had ceased motion.
The train was heading towards what was known as the Atlantic Avenue Loop, a stretch of track that diverged from what later became the Orange Line to travel along the waterfront before meeting back up with the main line near North Station. The loop was abandoned due to declining ridership in 1938 and torn down for scrap during World War II.
The curve, shown in a 1901 photo (from the Boston City Archives):
You can still see an echo of the old tracks at the corner today: There's a single-story building where the elevated used to go.