The collision occurred around 500km from the port city of Karachi on Friday.
At least one person has been killed and 40 injured after a train derailed in southern Pakistan.
The train derailed between the Rohri and Sangi stations in the southern Sindh province on Sunday and caused a temporary suspension of railway traffic in both directions, said Kamran Lashari, a railway official.
The 18-car train that departed from Karachi for the eastern city of Lahore derailed and six fell into a shallow ditch, Lashari added.
It was not immediately clear how many passengers were on board and what caused the derailment.
Darkness and the remote location of the derailment caused delays in rescue efforts, rescue official Muhammad Arshad said, adding that the body of the woman who died and 40 injured passengers were taken to hospitals in nearby towns.
Train accidents are common in Pakistan, where successive governments have paid little attention to improving the poorly maintained signal system and ageing tracks.
Last month, at least 18 people, including women and children, were killed when a passenger train collided with a bus at a crossing in southern Pakistan.
More to follow …