Indian officials say evidence has been found suggesting that the fire may have been deliberately set off by up to two homemade bombs.
Officials say the victims were apparently mainly Pakistanis, along with some Indians.
Indian authorities have described the incident as a suspected "terrorist" act possibly aimed at disrupting the peace process between India and Pakistan.
The Pakistani government has denounced the incident as "terrorism" and called on India to punish the perpetrators.
The fire is reported to have engulfed two carriages as the train traveled early today near the town of Panipat, north of New Delhi, in the northern Indian state of Haryana. It had left from New Delhi on a trip to Atari, near the Pakistani border.
Reports quoting witnesses suggest some of the victims may have been trapped in the burning train due to bars across the windows.
(compiled from agency reports)