Federal investigators said technology known as positive train control would have prevented the deadly derailment of an Amtrak train south of Tacoma late last year.

Related: How Life-Saving PTC Technology Works — And Why It Didn't Stop Amtrak Crash

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Three people died and 62 were injured when a Seattle-to-Portland train derailed on the first trip along a new inland bypass designed to save time.

The full federal investigation into the cause of the crash will take months, but a preliminary National Transportation Safety Board report released Thursday confirms the train was going almost 50 miles an hour over the posted speed limit.

Read the report: Preliminary Report Railroad Amtrak Passenger Train 501 Derailment DuPont, Washington

Investigators said video from seconds before the derailment shows the engineer and a conductor were not using cell phones or other electronic devices that could have distracted them. The engineer did appear to apply the train’s brakes just before the crash and made a comment about going too fast six seconds before the derailment. Signs about the speed limit were posted two miles ahead of where the train derailed.

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Positive train control is a congressionally mandated safety technology designed to prevent derailments caused by speed. It can automatically slow or stop trains.

NTSB investigators said the technology would have prevented the Amtrak crash: “In this accident, PTC would have notified the engineer of train 501 about the speed reduction for the curve; if the engineer did not take appropriate action to control the train’s speed, PTC would have applied the train brakes to maintain compliance with the speed restriction and to stop the train.”

Related: 911 Calls Show Chaos Of Deadly Washington Amtrak Derailment

Trains on the new Amtrak route were scheduled to get positive train control next year, but officials opted to open it for service before positive train control was in place. Federal regulators have pushed back the deadline for installing PTC on all U.S. rail lines to the end of this year. Positive train control is not in place for Amtrak passenger trains along the rest of the route from Seattle to Portland, including the Puget Sound stretch that is being bypassed by the new route.

The NTSB report also estimates total damage from the crash at $40.4 million. That doesn’t include the potential costs to Amtrak and government agencies from lawsuits: The conductor who was in the front locomotive when the train crashed sued Amtrak Wednesday, alleging the crew did not receive enough training on the new route. The conductor’s lawyer said his client was on the locomotive to familiarize himself with the route and was looking at paperwork as the train approached the curve where it came off the tracks.

He also said train crews were primarily trained on the new route, which avoids sharing lines with freight traffic along South Puget Sound, at night and in large groups.

At least one passenger on the derailed train has also sued Amtrak. The lawyer in that case said at least nine other people injured in the crash also plan to sue.

NTSB investigators haven't yet interviewed the engineer or conductor because of their injuries, according to the report.