BAHANAGA, India - Rescuers and families searched through mangled train carriages on Sunday for more victims of India's worst rail crash in more than two decades with signal failure emerging as the likely cause.

At least 275 people were killed on Friday when a passenger train hit a stationary freight train, went off the tracks and hit another passenger train passing in the opposite direction near the district of Balasore in the eastern state of Odisha.

The death toll, earlier estimated at 288, was revised down on Sunday after it was found that some bodies had been counted twice, according to a statement by Odisha Chief Secretary Pradeep Jena to ANI news agency.

Five more bodies were brought to a school being used as a mortuary near the scene of the accident early on Sunday.

"We do not know how many more bodies will come," a health worker said.

State-run Indian Railways, which says it transports more than 13 million people every day, has been working to improve its patchy safety record because of ageing infrastructure.

Prime Minister Narendra Modi, who faces an election due next year, visited the scene on Saturday to talk to rescue workers, inspect the wreckage and meet some of the nearly 1,200 injured. "Those found guilty will be punished stringently," Modi said.

Preliminary investigation

A preliminary investigation has indicated that the Coromandel Express, heading to Chennai from Kolkata, moved out of the main track and entered a loop track – a side track used to park trains – at a speed of under 130 kph (81 mph) and crashed into a freight train that was parked on the loop track, a railway official said.

The crash caused the engine and the first four or five coaches of the Coromandel Express to jump the tracks, topple and hit the last two or three coaches of the Yeshwantpur-Howrah train heading in the opposite direction at around 115 kph at the same time on the second main track, the person said.

This caused the Yeshwantpur-Howrah train to also jump the tracks and resulted in the massive wreckage, said the source who spoke on condition of anonymity as they are not authorised to speak to the media.

The drivers of the two passenger trains are injured but survived the crash, the person said.

Restoration work

Workers with heavy machinery were clearing the damaged track, wrecked trains and electric cables, as distraught relatives looked on.

More than a 1,000 people are involved in the rescue, the Railway Ministry said on Twitter.

"The target is by Wednesday morning the entire restoration work is complete and tracks should be working," said Railway Minister Ashwini Vaishnaw.

At a business centre where bodies are being taken for identification, dozens of relatives waited, many weeping and clutching identification cards and pictures of missing loved-ones.

Kanchan Choudhury, 49, was searching for her husband at the centre. Five people from her village were travelling on the train, of whom four were being treated at the hospital for injuries. However her husband was found dead, Kanchan Choudhury told Reuters as she wept while waiting to claim compensation at a counter in the centre, carrying both her and her husband's identity cards.

Families of the dead will get 1 million rupees ($12,000) in compensation, while the seriously injured will get 200,000 rupees, with 50,000 rupees for minor injuries, Vaishnaw said on Saturday.

U.S. President Joe Biden, Canadian Prime Minister Justin Trudeau, British Prime Minister Rishi Sunak and French President Emmanuel Macron have expressed condolences.