A New York commuter train that derailed, killing four people, was travelling nearly three times faster than the speed limit, officials said.
The seven-carriage train had been travelling at 82mph before entering a 30mph speed limit zone on a curved section of the track where it crashed.
The train's brakes were working but they were applied "very late in the game", National Transportation Safety Board member Earl Weener told reporters.
He added that investigators were considering a driver error being the cause of the crash but had not yet ruled out other possibilities.
More top news
GPs have a public duty to tell authorities if a patient is driving against medical advice, new guidance from the GMC says.
The Government may be about to announce a new levy on council tax of up to 2% to replenish social care budgets.
How do you solve a £4.4 billion hole like tax credits? At 12.30pm on Wednesday, we'll find out.