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The scene where an Amtrak passenger train derailed on a bridge over interstate highway I-5 in DuPont, Washington, U.S. Dec...

Everything we know about the Amtrak train derailment (so far)

Investigators are still trying to piece together exactly what happened Monday when an Amtrak train derailed during morning service, killing at least three people and injuring dozens more.

Here’s what we know so far.

What happened?

Around 7:38 a.m. PST Monday, Amtrak Cascades Train 501 ran off the tracks as it crossed an overpass, sending cars crashing off the rails and onto Interstate 5 below.

It was the first day of service for a new high-speed route between Seattle and Portland. Thirteen cars left the track, officials said, and several vehicles, including two tractor trailers, were damaged on the highway below.

The 467-mile Cascades route connects 18 cities between Eugene, Oregon and Vancouver, British Columbia, according to Amtrak.

How many people died or were injured?

About 80 passengers and five crew members were on board when the train went off the tracks in DuPont, Washington, south of Tacoma, near the Eagles Pride Golf Course, Amtrak said in a statement. Three people died and another 10 people were injured and in serious condition. More than 70 people were injured, 10 of them seriously, according to the Washington State Patrol.

“On behalf of everyone at Amtrak, we are deeply saddened by all that has happened today,” Amtrak President Richard Anderson tweeted Monday. “We will do everything in our power to support our passengers and crew and their families.”

How fast was the train traveling?

The National Transportation Safety Board said a data recorder revealed that the Amtrak train traveled at 80 miles per hour — 50 miles over the speed limit — when it derailed, the Associated Press reported.

The train was part of an $800 million federal high-speed rail project launched in 2014 under the American Recovery and Reinvestment Act, according to Amtrak.

It was not operating with new automatic braking technology, called “Positive Train Control,” mandated by Congress after a 2008 crash in California, USA Today reported. The technology must be operational by 2018. In Washington, parts of the system have been installed, but it’s still in testing. The system as a whole “hasn’t yet been linked together or certified as operational,” a transit spokesperson told USA Today.

It’s not clear what role speed or other factors played in the crash.

What’s next?

Amtrak opened a passenger and family assistance center at a Courtyard Marriott in Tacoma, Washington, along with an incident hotline at 800-523-9101.

Federal investigators will be on the scene of the crash for at least a week, an NTSB spokesperson told reporters Monday night.

Among the things investigators could focus on, CNN says: the condition of the track, the speed of the train and conversation between the train’s crew members captured on the train’s “black box.”

“At this time, we will not speculate about the cause, and we encourage others not to speculate as well,” Amtrak said in a statement.