A commuter train's on-board camera captured a fiery crash with a pickup truck abandoned by its driver, and federal investigators say the video could give a big boost to the search for a cause.

The video, taken from the outward-facing camera on the front car of the Metrolink train bound for Los Angeles, was sent back to the Washington home of the National Transportation Safety Board for analysis, board member Robert Sumwalt said at a Wednesday afternoon briefing near the Oxnard crash site.

Sumwalt also said that while the truck wasn't stuck in the way that vehicles sometimes get trapped between railroad crossing safety arms, investigators have not ruled out that the truck was somehow stranded and will determine why it traveled 80 feet down the tracks and remained there with its parking brake engaged.

"I don't think anybody would put a car or truck on ... railroad tracks and not try to get it off if there's an approaching train," Sumwalt said.

Three of five train cars derailed and 30 people were injured, four critically, after the Tuesday pre-dawn crash.

The truck driver, Jose Alejandro Sanchez-Ramirez, a 54-year-old from Yuma, Arizona, was arrested on suspicion of leaving the scene of an accident with injuries and was expected to be arraigned Thursday afternoon.

His attorney said Ramirez made repeated attempts to get the vehicle off the rails and then ran for his life as the train approached.

He accidentally drove onto the tracks and made the situation worse by continuing forward in an attempt to get enough speed to get his wide pickup over the rails, attorney Ron Bamieh said. When that effort failed, he tried to push the truck and then fled before the impact.

"He hits his high beams trying to do something. He's screaming. He realizes, 'I can't do anything,' and then he tries to run so he doesn't get killed," Bamieh said. "He saw the impact, yes. It was a huge explosion."

Police said Ramirez was found 45 minutes after the crash 1.6 miles away, though Bamieh said he was only a half-mile away and that he has phone records that show he spoke with police much sooner.

"When someone goes through a huge trauma like that and not only thinking they almost died, but they think other people are dead and you don't know what to do and you're confused ... what is a normal reaction to such an event?" Bamieh said.

Police said Ramirez did not call 911 and made no immediate effort to call for help. But Bamieh said Ramirez, who doesn't speak English well, tried to get help from a passerby, tried calling his employer and eventually reached his son to help him speak with police.

Police would not discuss drug and alcohol test results, but Bamieh said he was told there was no sign Ramirez was impaired.

Ramirez had a drunken driving conviction in Arizona in 1998 and a pair of traffic citations. Bamieh said the citations were minor and the DUI was too old to be relevant to the current circumstances.