At least 10 people were injured on Tuesday when four bogies of the Peshawar-Lahore bound Jaffar Express derailed in Gujranwala, rescue officials said.
The train derailed near the Qila Chand bypass and the bogies fell over into water gathered by the side of the rail track, they added.
Rescue teams used ladders to climb through the windows of the train and pull out passengers trapped inside, the sources said.
Army troops arrived at the site of the accident to assist civil administration in rescue efforts, Inter-Services Public Relations said.
Around 50 passengers have been pulled out so far, rescue officials said, adding that 10 among them were injured.
The injured are being transferred to District Headquarters Hospital while the rescue operation is ongoing.