I heard that a MFL (Market Frankford Line) here in Philly derailed before.
http://en.wikipedia.org/wiki/Market%E2%80%93Frankford_LineMarch 7, 1990: Three people were killed and another 162 were injured when the last three cars of six-car train #61 derailed leaving 30th Street Station westbound at 8:20AM. It is believed that one of the traction motors dropped out of the rear truck on the third car (M3) somewhere between 15th and 30th street stations, and it became entangled in a switch immediately upon leaving 30th street station. The front truck of the fourth car (M3 #818) followed the third car, while the rear truck of the fourth car took the diverging track, causing the car to shear halfway upon striking the steel pillars separating the tracks beyond the switch.