California regulators have issued a temporary order banning all train operators from using cellphones while they are on duty.

The California Public Utilities Commission unanimously passed an emergency order Thursday that bans the use of cellphones and all other personal electronic devices while operating a train.

The ban comes less than a week after a commuter train ran a stop signal and slammed into an oncoming freight train near Los Angeles, killing 25 people and injuring more than 130 others.

Federal safety authorities said Wednesday that an examination of phone records showed that the engineer on the commuter train did send text messages while on duty the day of the collision, but officials would not say when the messages were sent or whether text messaging played a role in the collision.

Safety review

Federal safety officials are still trying to determine the exact cause of the crash. The National Transportation Safety Board found no problems with the signals or tracks, and has narrowed its investigation to human error.

In Washington, Senator Dianne Feinstein introduced legislation Tuesday requiring the installation of technology to prevent train crashes and warned that there would be more disasters without it.

The California Democrat hopes Congress will pass her requirement for so-called positive train control before recessing at the end of next week. The House and Senate have already passed separate legislation to implement the technology but the differing versions have not been reconciled.

The technology is designed to engage the brakes if a train misses a signal or gets off track. It has been installed on just a fraction of U.S. rail tracks.

Feinstein blamed "a resistance in the railroad community in America" to the price tag of installing the systems.

Failure to act now, she said, amounts to "negligence, and I'll even go as far to say I believe it's criminal negligence not to do so."

In July 2007, Metrolink Chief Executive David Solow warned Congress that requiring the safety devices would involve "substantial cost," according to the Los Angeles Times. A Metrolink spokesman declined comment when called by The Associated Press.

The Association of American Railroads, the lobbying arm for the freight railroad companies, has said it does not oppose the legislation but is concerned that the technology has not been perfected.

With files from the Associated Press