A Southern California commuter train slammed into a truck and derailed in a rural area near Oxnard on Tuesday, injuring dozens of people including four critically, authorities said.
The truck caught fire and three Metrolink rail cars derailed and toppled over after the crash shortly before 6 a.m. At least one other car derailed but stayed upright.
Twenty-eight people were transported to area hospitals with injuries that ranged from "significant head trauma" to back and neck injuries, said Steve Carroll of Ventura County Medical Services. Twenty-three people did not require transportation to medical services, Carroll said.
Sergio Martinez, a battalion chief for the Oxnard Fire Department, told CNN the truck driver fled the scene and that authorities found him unhurt and took him into custody.
Local resident Jorge Garcia, 56, told the Los Angeles Times was getting ready for work when he heard the crash.
"I just heard a bang and then an explosion," Garcia told the newspaper. "It was a big old boom. And then the ambulances started. ... You could see it was something big."
The National Transportation Safety Board tweeted: "We are aware of the rail accident near Oxnard, CA and are currently gathering information about the event."
It later tweeted that it was "launching a team" to the site. Oxnard is about 75 miles west of downtown Los Angeles.
Three of the four derailed cars featured a "crash energy management" system aimed at easing the impact of a crash on passengers, a Metrolink official told the Times.
Metrolink operates a rail network of almost 400 miles on seven regional lines: Ventura County, Antelope Valley, San Bernardino, Riverside, Orange County, Inland Empire-Orange County and 91 Line. Trains can travel at speeds of up to 90 mph.
On September 12, 2008, a Union Pacific freight train and a Metrolink commuter train collided head-on, killing 25 people. That crash was the deadliest accident in Metrolink history.
Last year Metrolink unveiled a new safety program, saying it was the nation's first rail line to introduce "positive train control" technology. The technology uses GPS and other systems to determine when it should override the train engineer and slow or stop a train to avoid an accident.