Egyptian officials have charged three men with involuntary manslaughter over a train collision that left 18 dead

Two train conductors and a third man, who allegedly abandoned his monitoring post, have been taken into custody.

The crash happened on Saturday on a line south of the capital, Cairo, and was caused by a water buffalo that had wandered onto the tracks.

The first train stopped after hitting the buffalo and was then rear-ended by the second train travelling at full speed.

The collision badly damaged the front carriages of the second train and crushed the rear carriages of the stationary train.

Egypt's rail network has a poor safety record and has been hit by a series of fatal accidents, usually blamed on poorly maintained equipment.

The country's worst railway disaster took place in February 2002 when a train heading to southern Egypt caught fire, killing 363 people.