Nearly a dozen carriages of a packed express jumped the rails in the northern state of Uttar Pradesh on Sunday, while a second derailed as a result of a suspected bomb attack in the restive northeastern state of Assam.
In the first accident, the force of the derailment caused some carriages to mount each other and badly crushed several others, making it difficult for the emergency services to get to survivors.
"We are still searching," the army officer leading the rescue operation, Colonel A.D.S. Dhillon, told.
Later Sunday, at least 100 passengers were injured -- 20 of them critically - when their train derailed in the northeastern state of Assam as the result of what police believe may have been a bomb placed on the rails by separatist rebels.
The Guwahati-Puri Express was nearing Ghograpara, about 70 kilometres from Assam's main city of Guwahati, when it was apparently hit by a strong blast.
In Uttar Pradesh, police said at least one Swedish citizen was among the dead from the earlier derailment of the Kalka Mail, which was heading from Howrah, the main station for the eastern city of Kolkata, across India to the capital New Delhi.
The Press Trust of India news agency reported the driver was among the injured and that the train, carrying about 1,000 people, was moving at near its top speed of 108 kilometres an hour when it left the tracks.
Prime Minister Manmohan Singh, who is acting railways minister, expressed "deep sorrow and shock at the loss of lives."
Anxious relatives and friends of the passengers gathered at Howrah and other stations along the line seeking information about their loved ones.
