LOS ANGELES -- A new proposal would have Metrolink engineers watched by real-time surveillance cameras, but the idea is drawing criticism.

The proposal comes more than three months after a head-on collision between a Metrolink train and a freight train in Chatsworth killed 25. Investigators determined that the engineer of the Metrolink train was sending text messages immediately prior to the accident, in violation of Metrolink safety policies.

The cameras, which would be installed within six months, would help ensure that safety procedures are followed, according to the Metrolink board. They would also eliminate the need for an extra crew member, the board says.

Railroad unions counter that the plan is costly and will be mostly ineffective. California Sen. Diane Feinstein agrees.

What's more, they feel the cameras would be a major invasion of privacy.

The proposal is getting attention at about the same time as new findings about the crash are being released. Investigators say that the position of trackside warning signals could have contributed to the crash.

Apparently, several hundred yards and a few seconds before Metrolink engineer Robert M. Sanchez arrived at the Chatsworth station, he passed a critical solid yellow signal that should have warned him to stop at the next light.

Experts say, however, that the warning signals are too far apart, leaving too much time for engineers to forget and offering too many distractions in between.