As investigators combed through the wreckage of the Amtrak train, officials vowed to restore confidence in rail safety.
The passenger train derailed Monday after careening around a curve at almost three times the speed limit, hurling passenger cars off an overpass onto rush hour traffic below.
Three people were killed and about 100 injured when the train was flung off the tracks in DuPont, Washington. The National Transportation Safety Board member Bella Dinh-Zarr said it was unclear why the train had been traveling 80 mph in a 30-mph zone.
"There are a thousand unanswered questions about this right now," said Washington Gov. Jay Inslee, referring to the incident. "One of the questions is could that speed control have made a difference? We don't know that for sure at the moment either."
Amtrak's incoming CEO, Richard Anderson, called the crash a "wake-up call" and said the company was committed to running "the safest railroad in the world."
"It's not acceptable that we are involved in these kinds of accidents. We are terribly sorry to the people that are involved," Anderson said on Tuesday.
It was a disastrous start for the Amtrak Cascades 501, which had set off Monday on its inaugural journey with paying customers, on a new section of the route from Seattle to Portland.
-- Two of the three people who died were train enthusiasts, reported CNN affiliate KIRO.
-- All crew members are hospitalized and the NTSB is setting up interviews with them. "As they are able, we will get more information from them. We want to be respectful of their injuries," Dinh-Zarr told reporters Tuesday.
-- The emergency brake appeared to have been automatically activated, rather than by the engineer during the accident, Dinh-Zarr said.
-- Two people had been in the cab in the front locomotive during the crash, she said. The engineer was joined by a conductor who was learning the new route, she said. Amtrak's Anderson said that is not unusual.
-- The engineer had been on this stretch of track before, NTSB lead accident investigator Ted Turpin said. Investigators don't yet know how many hours of previous travel that involved.
-- Data recorders from the front and rear locomotives have been recovered, Dinh-Zarr said. Cameras from the train were damaged and have been sent to Washington, DC to see whether video can be retrieved.
Two of the victims were identified as Jim Hamre and Zack Willhoite, the Rail Passengers Association said. They were riding the first trip on the new service route.
The two friends traveled to ride trains together, CNN affiliate KIRO reported. They were also members of All Aboard Washington, a rail advocacy group in their home state.
"Jim was among the country's most respected and effective rail advocates and a good friend and mentor to me. I will miss his counsel, and our community is poorer for his loss," Rail Passengers Association President Jim Mathews said in a statement. "Both Jim and Zack have been advocates of transit and passenger rail for decades, and we can't thank them enough for their work."
Willhoite worked as an IT customer service support specialist for the public transit agency in Pierce County, Washington.
Those who survived were injured and severely shaken.
"It was like being inside an exploding bomb," passenger Charlie Heebner, 79, told CNN affiliate KOMO.
He and his wife, Beverly, had been looking forward to the route's inaugural run. But their adventure was soon marred by carnage. They were catapulted across the train car and had to crawl to safety.
"There was this body lying there," Beverly Heebner said. "I mean he hardly had any clothes on, the clothes had just been ripped off of him. And he was obviously dead."
'A thousand unanswered questions'
At the crash site, cranes hovered over the wreckage that had spilled onto Interstate 5 as flatbed trailers hauled off the mangled train cars.
Investigators will likely examine the track, human performance, operations and the mechanics of the train. The track in Washington state had undergone millions of dollars of improvements and weeks of testing.
"We have to assure people's confidence in rail transit," said Gov. Inslee. "It's very difficult to understand but rail transit is still the safest method of transit today. But that's not good enough for us. We want zero accidents and zero tragedies of this nature."
Positive train control (PTC) -- technology that automatically slows down and stops a speeding train -- wasn't activated, much to the dismay of the NTSB official.
Sound Transit, which owns the segment of the tracks where the crash happened, had Centralized Traffic Control (CTC), which is not PTC, said Dinh-Zarr on Tuesday.
"CTC cannot enforce speed restrictions on a train like PTC can. The locomotive was in the process of getting a system of PTC installed but it was not yet functional," she said.
NTSB has recommended PTC for decades. Railroad companies have until the end of 2018 and a possible extension to 2020 to implement the system.
Amtrak CEO Anderson told reporters on Tuesday: "It's not clear yet from the NTSB whether PTC would have prevented the accident or not. We really must wait for the NTSB to give us that information."