A fire swept through a train car packed with sleeping passengers in southern India on Monday, killing at least 32 people and sending panicked survivors rushing for the only clear exit once the train stopped, officials said.

Investigators found charred remains of victims still in their sleeping berths and were struggling to identify them.

A railway station worker noticed the burning coach as the overnight train from New Delhi to the southeastern city of Chennai passed through the town of Nellore at about 4 a.m., local official B. Sridhar said. Nellore is about 310 miles south of Hyderabad, the capital of Andhra Pradesh state.

Once the alarm was raised, the train was stopped and the coach was detached from the rest of the train to prevent the blaze from spreading.

Passengers were evacuated once the train was halted.

"Since the fire had engulfed one door of the coach, people had to rush to the other end of the coach to exit," Sridhar said by telephone from the accident site.