India’s railway Minister has suggested a signal fault led to the Odisha rail disaster, with a “change in electronic interlocking” the likely cause.
Ashwini Vaishnaw later said the cause and people responsible for the deadly three-train crash in eastern India had been identified but did not elaborate.
India’s Railway Board said there had been “some kind of signalling interference” rather than failure.
A report into India’s worst rail accident this century is due later.
Meanwhile the death toll has been revised down to 275 after some bodies were counted twice, officials said.
Of the 1,175 injured people taken to hospital, 793 have been discharged. Some families are still searching for their loved ones.
In railway signallingthe electronic interlocking system” and said investigations indicated “some kind of a signalling interference” rather than failure.
“Whether it was manual, whether it was incidental, whether it was weather related, whether it was because of wear and tear related, whether it was a maintenance failure, all that will come out after the inquiry,” she added.
Infrastructure expert Partha Mukhopadhyay told the BBC it should not be possible for green signals to display on the main line if the track is set for the loop.
“Signal interlocking is supposed to be failsafe and this level of failure is quite unprecedented,” Mr Mukhopadhyay, from the Delhi-based think tank Centre for Policy Research, said.
On Saturday Prime Minister Narendra Modi visited the crash scene and vowed that anyone found guilty would be “punished stringently”.
Around 2,000 people are thought to have been on board the two passenger trains – the Coromandel Express, travelling between Kolkata (formerly Calcutta) and Chennai (formerly Madras) and the Howrah Superfast Express travelling from Yesvantpur to Howrah – when the crash happened at about at about 19:00 (13:30 GMT) on Friday.
Odisha state official Pradeep Jena told the BBC that at least 187 bodies remained unidentified and officials were uploading pictures of the victims on government websites and would carry out DNA testing if needed.
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Rescue work was completed on Saturday and efforts were underway to clear wreckage and restart train traffic, officials said.
India has one of the largest train networks in the world with millions of passengers using it daily, but a lot of the railway infrastructure needs improving.
Trains in India can get very packed at this time of year, with a growing number of people travelling during school holidays.
The country’s worst train disaster was in 1981, when an overcrowded passenger train was blown off the tracks and into a river during a cyclone in Bihar state, killing about 800 people
