An Amtrak passenger train derailed on a bridge over a major highway in Washington state on Monday morning, sending part of the train crashing down onto Interstate 5 and killing several passengers, authorities said.A spokesman for the local sheriff's office, Ed Troyer, told reporters at the scene there were "multiple" deaths but did not have a specific number to report. He also said no motorists were killed, though some were injured when part of the train struck several vehicles.Amtrak passenger Chris Karnes told local news outlet KIRO 7 that passengers were forced to kick out train windows in order to escape, because emergency doors were not functioning properly following the derailment."We had just passed the city of DuPont and it seemed like we were going around a curve," Karnes said. "All of a sudden, we felt this rocking and creaking noise, and it felt like we were heading down a hill.""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. People were screaming," he added.