The train derailment near Tacoma, in the US state of Washington, happened during the Monday morning rush hour and multiple people witnessed it or arrived moments later.
Train passenger Chris Karnes told local news outlet KIRO 7 that passengers were forced to break train windows to escape because emergency doors were not functioning properly after the derailment.
“We had just passed the city of DuPont and it seemed like we were going around a curve,” said Karnes.
“All of a sudden, we felt this rocking and creaking noise, and it felt like we were heading down a hill.”
Danae Orlob was travelling on Interstate 5, where the accident happened, and told CNN: "There were cars [train carriages] on both sides of the bridge falling onto the freeway."
About 70 people were aboard the train, the state transportation department reported.