LOS ANGELES, United States (AFP) — An Amtrak passenger train traveling on a new route for the first time derailed Monday in Washington state, killing “multiple” people as cars flew off a bridge onto a busy highway at the height of rush hour, officials said.

Pictures from the scene near the city of Tacoma showed one Amtrak train car overturned and crushed on the interstate highway and others dangling from the overpass.

The incident occurred over Interstate 5, a busy highway that connects the busy Seattle metro area to the state’s capital city Olympia to the southwest.

The train, which was carrying 78 passengers and five crew, was part of a newly expanded rail service along the route linking Seattle and Portland, Oregon — featuring new locomotives and a new bypass to make the trip quicker.

The train derailed about halfway between Tacoma and Olympia on a curve that passes over the highway during the morning rush hour at about 7:40 am (1540 GMT).

“There’s multiple fatalities,” said Ed Troyer, spokesman for the Pierce County Sheriff’s Department.  

“It’s pretty horrific,” he said.

Troyer put no number on the fatalities, but local media said at least three people were killed. None of the people in vehicles travelling on the highway below the train were killed, according to Troyer.

Local officials had expressed safety concerns in recent months ahead of the start of the new, faster service. The National Transportation Safety Board has sent a team of experts to investigate the incident.

Dozens of people were reportedly taken to area hospitals for treatment, with several said to be in serious condition.

“When we got to the scene, it was obvious there were fatalities and injuries, and some people were able to get off the train,” Troyer said.

“No fatalities on the roadway. As you can see by the large response, we have taken them out and people that were able to walk are under the tents being cared for by multiple groups,” he said.

– ‘People were screaming’ –

The accident snarled morning rush hour traffic and officials warned that that section of Interstate 5, would be blocked for at least the rest of the day.

“We had just passed the city of DuPont and it seemed like we were going around a curve,” passenger Chris Karnes — the chair of the Pierce Transit Community Transportation Advisory Group (CTAG) — told local CBS News affiliate KIRO-TV.

“All of a sudden, we felt this rocking and creaking noise, and it felt like we were heading down a hill,” said Karnes, adding that several cars had gone off the tracks and passengers kicked out the windows to escape.

“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.”

Karnes said the tracks were supposed to have been upgraded to accommodate higher speeds.

“I’m not sure what happened,” he said.

– Safety concerns –

A passenger identified as Alex told the local KOMO News TV channel that the train had attracted rail buffs excited over the new service.

“There were a bunch of people who wanted to be a part of this historic moment and they were on board the train this morning headed for Portland,” he said.

The new service came after tens of millions of dollars were invested to modify a part of the tracks on the line, improve signalling and add newer locomotives.

Local officials had worried about trains going at higher speeds through the curves in the area. The trains were expected to reach speeds of 79 miles (127 kilometers) per hour through the densely populated area with the improved systems and track.

In early December, Don Anderson — the mayor of Lakewood, Washington, a Tacoma suburb just a few miles from the accident site — had warned that more needed to be done to ensure safety on the route.

“Come back when there is that accident, and try to justify not putting in those safety enhancements,” he said, according to KOMO News.

US President Donald Trump said the accident underscored the need to invest in infrastructure.

“The train accident that just occurred in DuPont, WA shows more than ever why our soon to be submitted infrastructure plan must be approved quickly,” he wrote.

“Seven trillion dollars spent in the Middle East while our roads, bridges, tunnels, railways (and more) crumble! Not for long!”

The new train cars were to be pulled by new Siemens Charger locomotives that include an “on-board positive train controls system,” designed to automatically stop the train in dangerous situations and mandated for trains around the country.

But on the Washington train, 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.  

In 2015, an Amtrak train going far over the designated speed for a stretch of curves in the track in Philadelphia derailed, killing eight.

At the time, analysts said positive train control technology could have prevented the accident.