Federal investigators say inward-facing cameras also showed that the crew were not using any personal electronic devices prior to the crash.
At least three people died, and more than 70 were taken to hospitals, after passenger train cars plunged onto traffic below on an interstate in Washington.
Philadelphia's district attorney had previously said there was not enough evidence to prosecute the 34-year-old engineer, but the state attorney general disagreed and filed charges Friday.
Rescue operations are continuing to save those trapped in the damaged carriages and remove the bodies of those killed.
The Altamont Corridor Express was traveling from San Jose to Stockton when it derailed in Alameda County. It was a “miracle” no one was killed, authorities said.
"There are no immediate reports of life-threatening injuries following the derailment," the national railroad said.
Eight people have been confirmed dead as a result of the derailment near Philadelphia. These are some of their stories.
A train carrying crude oil derailed and exploded near Charleston, destroying one home and contaminating local water supply. One person was treated for possible respiratory problems.
The train derailed in downtown Lynchburg, Va. No injuries have been reported.
The train hit an escalator at the end of the platform. Update: The operator of the train has told her union officials that she dozed off before the train jumped the tracks.
New York City's mayor kept playing golf in Bermuda after learning about a deadly train accident in his city. Here's why that's OK.
The engineer snapped out of the daze just moments before the deadly crash and slammed on the brakes, his attorney said. But by then, it was too late.