Two children were pulled out alive from an overturned coach of the Indore-Patna Express in Pukhraya as rescuers looked for survivors among the heaps of metal and scattered baggage.
The two boys, aged six and seven, were pulled out from the S3 bogie of the train, police officials said.
A woman, suspected to be the mother of the boys, was found dead near them, police said.
Two girls are also trapped in another coach, AK Singh, NDRF Commandant said.
"There is another coach that was smashed and two girls are still trapped inside it. We can't use cranes to pull them out. But I want to assure you that they will be rescued. After that, we will execute a search operation to find the bodies before closing the operation," he said.
Singh said crowd management was obstructing rescue operation.