LOS ANGELES — Federal investigators plan to subpoena the cell phone records of the engineer who is said to have been exchanging text messages in the minutes before his commuter train ran through a red signal and smashed into a freight train here Friday, killing 25 people.

Kitty Higgins, a member of the National Transportation Safety Board, which is leading the investigation, said Sunday that the agency would subpoena the records and also question the young men who told KCBS-TV that they had taken part in an exchange of text messages with the engineer just before the crash.

Whether the engineer, Robert Sanchez, who was killed, had been distracted is among the bevy of questions investigators are seeking to answer. Others include whether the three-car Metrolink train and track equipment were functioning properly and what role dispatchers controlling train traffic might have played.

In the deadliest train accident in the country in 15 years, the commuter train, headed from Union Station here north to the suburbs, collided head-on with a Union Pacific freight train during rush hour Friday near a residential area of the San Fernando Valley. The crash, which also injured 135 people, nearly obliterated the front car of the commuter train and trapped the living and the dead for hours.

Officials at Metrolink have said the engineer passed through a red signal without stopping, probably causing the accident.

But federal investigators cautioned against jumping to conclusions and predicted that the investigation could span many months.

Why the two trains were on the same track heading toward each other at about 40 miles per hour has puzzled officials. The claim of the text message exchange is among the more sensational factors officials are investigating.

KCBS-TV reports on Saturday quoted a group of young railroad buffs as saying they had a friendship with the engineer and displaying messages they said came from him immediately before the crash.

The last message, at 4:22 p.m., about a minute before the crash, tells one of the group that the engineer would be meeting another passenger train. It says, "yea ... usually (AT) north camarillo," apparently a reference to a town about 25 miles west of the crash site in the Chatsworth neighborhood in the San Fernando Valley.

One of the young men, Evan Morrison, would not comment Sunday and the others could not be reached or did not answer e-mail messages. Morrison is one of the more prolific within a group of rail devotees who post pictures of trains and other information on Web sites.