Investigators say a train which killed 7 people when it derailed in the US was going twice as fast as it should have been.
The National Transportation Safety Board says it will give the train's engineer a few days to recover before asking him about the crash near Philadelphia yesterday.
Philadelphia mayor Michael Nutter described the scene as "an absolute disastrous mess" and said not all of the more than 240 people on board have been accounted for.
He said: "I've never seen anything like this in my life. It is a devastating scene down there.
"We walked the entire length of the train area, and the engine completely separated from the rest of the train, and one of the cars is perpendicular to the rest of the cars. It's unbelievable."
The train, which was travelling from Washington DC to New York, was carrying 238 passengers and five crew members.
