Forensic investigators on Wednesday were trying to determine what caused a fire that engulfed two train cars and killed seven passengers, including an Australian researcher.
The fire broke out before dawn Tuesday as the express train was traveling in Jharkhand state on its way from Kolkata to the north Indian city of Dehradun.
The train's engineers managed to detach the two blazing cars from the rest of the train, but were unable to save seven people who died from suffocation or burns.
The victims included a 4-year-old girl and 21-year-old Kati Scanlan, from Australia's Tasmania province. She had been traveling with three fellow Australians, who survived and were being treated Wednesday for injuries including smoke inhalation.
The four women were in India to research Buddhism at the Bodh Gaya holy site in northern India, where tradition has it that Buddha reached enlightenment.
Australia's foreign affairs department said it was in contact with the surviving women, as well as with their families in Australia.
Arjun Munda, Jharkhand's chief minister, expressed condolences Wednesday as well as concern over India's high number of railway mishaps. He urged authorities to improve safety.
Accidents are common on India's railroad network _ one of the world's largest with some 14 million passengers daily. Most collisions and fires are most blamed on poor maintenance and human error.
On Wednesday, a passenger express train and a cargo train collided in a railway station in Orissa state, leaving four people injured. Authorities blamed the accident on a faulty signal.
Another train derailed Wednesday near Anantnag town in the Indian-controlled portion of Kashmir, and several passengers suffered minor injuries.