At least 25 people were killed and 55 others injured when a passenger train drove full-speed into the back of another on Saturday in Giza, southwest of the Egyptian capital, witnesses and police said.
A first class train, filled with passengers, rammed into a mostly empty stationary train on the same track, security sources said. At least two carriages were destroyed.
The sources said they believed the death toll could rise as rescue as recovery operations continued
The trains collided near the village of Guerzah, around 40 kilometers (25 miles) from Cairo, when one train stopped unexpectedly and another, also heading south from the capital, ploughed into it from behind, the security official said.
The first train, heading to Fayyum, 100 km (65 miles) south of Cairo made an unscheduled halt, apparently after hitting a cow.
However the second train, on a southbound journey from Cairo towards Assiyut, 400 km (250 miles) from the capital, travelled onwards at normal speed until it slammed into the back of the stationary train, the official said.
Al-Ayyat was the scene of Egypt's deadliest ever train crash when the bodies of at least 361 passengers were recovered from a train following a fire in February 2002.
Egypt's national railway system is the biggest in the Middle East, with nearly 5,2D0 km (3,150 miles) of track, according to Egyptian National Railways, which employs 86,2D0 people.
There have been other fatal crashes on the busy rail network.
In July 2008, at least 44 people died near Marsa Matruh in northwest Egypt when a runaway truck hurtled into bus, truck and several cars waiting at a level crossing, shunting the vehicles into the path of a train.
In August 2006 at least 58 Egyptians were killed and 144 wounded in a collision between two trains travelling on the same track. Following that crash, an Egyptian court sentenced 14 railway employees to one year in prison for neglect.