LOS ANGELES -

Federal investigators say they will seek the cell phone records of two teenagers and a train engineer as they probe whether text messages factored into a fiery commuter train crash that killed 25 in Southern California.

Kitty Higgins, a board member for the National Transportation Safety Board, says her agency is also talking with the two teens and their families. The teens told KCBS-TV that they received a text message from the engineer at 4:22 p.m. Friday, just moments before the deadly crash.

Higgins said that the engineer's cell phone was not recovered at the crash site yesterday.

She declined to say what the teens and their families have told investigators thus far.

The engineer, whose name was not released, died in the wreck.

Federal investigators continued yesterday to comb the twisted wreckage of the commuter train in the Chatsworth section of Los Angeles as fresh details emerged that a Metrolink dispatcher tried too late to warn the engineer that he was about to collide with a freight train.

Metrolink officials said Saturday that the commuter train's engineer apparently failed to heed a trackside red light near a junction with a railroad siding. But they did not disclose how they knew the red light was functioning properly.

Regular riders on the route said the Metrolink train heading toward Simi Valley, northwest of Los Angeles, often stops at the junction to wait for a Union Pacific freight train headed toward downtown Los Angeles.

But on Friday the Metrolink train continued north before the freight train had passed, tripping an alarm at the commuter line's dispatch center in Pomona, 30 miles east of Los Angeles.

A Metrolink dispatcher called the train and reached the conductor, according to a Metrolink spokesman. But by then, the crash had already occurred on the curve leading west toward Simi Valley.

Beyond the death toll, 135 passengers were injured, 40 of them critically, when the freight train's locomotive pushed the Metrolink engine back inside the first coach.

Yesterday morning, earthmovers were clearing broken passenger seats, shattered glass, insulation and detritus from both sides of the tracks. Waiting patiently a few yards away were sheriff's deputies wearing rubber gloves and holding cardboard boxes in which to store personal belongings passengers left behind. Others were collecting bloodied clothing and other items left behind at triage centers.

Cranes rumbled into position beside the disabled passenger car and crumpled engine. Deputies and Metrolink workers and federal investigators clambered in and around the cars, snapping photographs and recording video footage.

Among those who felt compelled to visit the crash site yesterday were Debbi Cherry, 42, and 10 members of her family.

"A close, close friend's daughter died here. She was 18," Cherry said of the victim, Maria Elena Villalobos. "I feel numb, and it makes me angry because of the negligence on the part of the engineer."

Metrolink's swift placement of blame Saturday prompted NTSB officials to say they were reserving judgment on the cause of the collision, and a union representing 125,000 rail workers - although not those who work for Metrolink - called the assignment of blame "terribly premature."

"The signals might not have been working" properly, said Frank N. Wilner of the United Transportation Union, noting that officials had not yet examined the "black box" and other crash-site evidence. "We don't know if there was glare or if he succumbed to a heart attack or a stroke."

The engineer had at least 10 years of experience working for Amtrak and more recently for a private company, Veolia Transportation, which has contracted with Metrolink to provide engineers since 2005, officials said. The train he drove Friday was carrying 225 passengers.

The engineer was certified specifically on the Los Angeles-to-Simi Valley route, his regular assignment, and was familiar with signal locations, officials said.

Moreover, the Union Pacific freight train and the 3:35 p.m. Metrolink train routinely passed each other near Chatsworth.

"That is a daily freight train. It's a regular traveler on those tracks," said Francisco Oaxaca, a Metrolink spokesman. The engineer is responsible for checking signals and abiding by them, Oaxaca said. Typically, when an engineer encounters a signal, he radios the train's conductor, who is supposed to radio back confirming the signal's color.

It wasn't clear whether that procedure was followed Friday.

The Associated Press contributed to this article.