Derailment

A derailment is said to take place when a vehicle such as a train runs off its rails. This does not necessarily mean that it leaves its track. Although many derailments are minor, all result in temporary disruption of the proper operation of the railway system, and they are potentially seriously hazardous to human health and safety. Usually, the derailment of a train can be caused by a collision with another object, the mechanical failure of tracks, such as broken rails, or the mechanical failure of the wheels.

History

In the nineteenth century derailments were commonplace, but progressively improved safety measures have resulted in a stable lower level of such incidents. In the US, derailments have dropped dramatically since 1980 from over 3,000 annually (1980) to 1,000 or so in 1986, to about 500 in 2010.

Causes

Derailments result from one or more of a number of distinct causes; these may be classified as: