"The next thing we know, we're being slammed into the front of our seats, windows are breaking, we stop, and there's water gushing out of the train".
Sheriff's spokesman Ed Troyer said no motorists were killed but several were injured when carriages struck vehicles.
It said the injured people were receiving treatment at Good Samaritan Hospital, Allenmore Hospital ad Tacoma General Hospital in the Pierce County, Washington State on the USA west coast.
Daniel Konzelman, and his girlfriend, Alicia Hoverson, were among the first on the scene after an Amtrak train derailed traveling along an overpass in Washington state. The locomotive and several of the train's passenger cars landed on the interstate.
It added that Amtrak service south of Seattle is temporarily suspended, but service from Seattle to points north and east is continuing to operate. "WSP is investigating this incident".
Autopsies underway for Canadian billionaires found dead
Police said homicide investigators are involved in the case, though the deaths have not officially been classified as homicides. Sherman's wife, Honey, was a member of the board of the Baycrest Foundation and the York University Foundation.
He said he and Hoverson climbed inside the trains and moved wreckage out of the way to find passengers who might be stuck inside. "I'm not sure what happened at this juncture".
"We got cars everywhere and down onto the highway", he said.
The train was reportedly travelling at more than 80 miles per hour when it derailed. However, it derailed 7:30 am local time in the city of DuPont, Washington.
"Come back when there is that accident and try to justify not putting in those safety enhancements, or you can go back now and advocate for the money to do it, because this project was never needed and endangers our citizens", he told local outlet KOMO news earlier in December.
The deadly crash "shows more than ever why our soon to be submitted infrastructure plan must be approved quickly", tweeted President Trump, who was briefed on the derailment.
But the technology was only expected to be used next year when it is activated on the entire rail corridor, according to the Washington State Department of Transportation.