Prosecutors in Alexandria have ordered the detention for 15 days of the drivers of two trains that collided near Alexandria on Friday killing dozens of people, state-run news agency MENA said on Sunday.
The prosecutors ordered the two drivers be detained and given drugs tests pending the results of a probe into the causes of the crash.
The two trains collided between Cairo and the coastal city of Alexandria, killing 42 people and injuring dozens more. One of the trains stopped on the tracks and the other train ploughed into it from behind, according to preliminary investigations.
One of the trains had been travelling to Alexandria from Cairo, while the other was coming from Port Said.
On Saturday, Transport Minister Hisham Arafat said the crash was caused by the Egyptian railway's manual-operation system and poorly developed infrastructure.
Egyptians have long complained that successive governments have failed to develop the dilapidated transport network and guarantee basic railway safety standards.
Several deadly railway crashes have taken place in Egypt over the years. In 2012, a train ploughed into a school bus south of Cairo, killing 50 people, mostly children.
The country's worst train disaster took place in 2002 when a fire swept through a passenger train heading to the south, killing some 360 people.