Passengers killed after Amtrak train derailment near Seattle

At least six passengers have been killed after an Amtrak train derailed on a bridge near Seattle, leaving at least one train car dangling onto the highway below.

The derailment happened on the first day that Amtrak trains began using a new track between the cities of Tacoma and Olympia in Washington state, according to the state's transportation department.

Seventy-eight passengers and five crew members were aboard when the train derailed about 64 km south of Seattle before 8am, Amtrak said.

Transitdocs.com, a website that maps Amtrak train locations and speeds using data from the railroad's train tracker app, says Train 501 was going 130 km/h moments before the derailment.

The state Department of Transportation posted information online about the US$180.7 million ($258m) project that says the maximum speed along that stretch of track is 127km/h.

The new route was designed to speed up service by removing passenger trains from a route along Puget Sound that is bogged down by curves, single-track tunnels and freight traffic.

The mayor of Lakewood, Washington, a city along the route, predicted a deadly crash. But Don Anderson thought it'd involve a fast-moving train hitting a car or pedestrian at a crossing.

Pierce County sheriff's spokesman Ed Troyer said multiple people were killed in the crash, but none of the fatalities were in cars and trucks when the train came off the tracks on to I-5.

President Donald Trump is using a deadly train derailment in Washington state to call for a boost to infrastructure spending.

In a tweet sent about three hours after the crash that authorities said killed at least six Monday, Trump says it shows "more than ever why our soon to be submitted infrastructure plan must be approved quickly."

Trump adds: "Seven trillion dollars spent in the Middle East while our roads, bridges, tunnels, railways (and more) crumble! Not for long!"Trump is expected to release a framework for increased infrastructure spending in January, relying on a mix of federal, local and private spending.

Chris Karnes was on the train, three or four cars back from the front.

"I'm not sure what got hit. I'm not sure what happened," Karnes said.

He was unhurt but medical tents have been set up in a median area between north and soundbound I-5, just south of DuPont.

"The only car that is on the tracks is the rear locomotive. There are several cars that are hanging over the overpass," Karnes said.

Amtrak said Train 501 offered service from Seattle to Portland.

"Emergency services are on the scene and Amtrak management is responding. Some injuries are reported," Amtrak said.

All southbound lanes of Interstate 5 were closed south of Joint Base Lewis-McChord, and motorists were being warned to avoid the area.

The train derailed just south of Tacoma, Washington.