The Montparnasse derailment occurred at 16:00 on 22 October 1895 when the Granville–Paris Express overran the buffer stop at its Gare Montparnasse terminus. With the train several minutes late and the driver trying to make up for lost time, it approached the station too fast and the driver's application of the train air brake was ineffective. After running through the buffer stop, the train crossed the station concourse and crashed through the station wall. The locomotive fell onto the Place de Rennes below, where it stood on its nose. Although the passengers survived, a woman in the street below was killed by falling masonry.

In rail transport, a derailment is a type of train wreck that occurs when a rail vehicle such as a train comes off its rails. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway system and they are a potentially serious hazard.