A cutting-edge proposal to focus live video cameras on engineers at the controls of Metrolink trains is drawing fire from employee groups and skepticism from California's senior U.S. senator.

In response to the Chatsworth disaster in September, which occurred just after the commuter rail service's engineer illicitly sent and received cellphone text messages, Metrolink officials are forging ahead with plans to use on-board surveillance cameras to enforce safety rules.

"We're talking about the ability to look into a [locomotive] cab in real time and see what's happening," said Metrolink board member Richard Katz, who Los Angeles Mayor Antonio Villaraigosa placed on the panel after the deadly Sept. 12 crash.

Metrolink appears to be among the first commuter rail systems in the country moving to install the live cameras. They could be on trains in as little as six months, officials say, part of a series of efforts to reduce the chances of another Chatsworth-like catastrophe.

Twenty-five people died and 135 were injured when Ventura-bound Metrolink 111 ran a red light and slammed head-on into a freight train, according to federal investigators.

Railroad unions say the surveillance proposal will be costly, ineffective and an invasion of privacy.

"You've got Big Brother looking over your shoulder," said Tim Smith, state chairman of the Brotherhood of Locomotive Engineers and Trainmen, which represents Metrolink train operators.

Live video would be chiefly "punitive in nature," he said.

The priority should be installing technology "to stop the impending doom" of a collision when an engineer passes out or makes an egregious error, he said.

U.S. Sen. Dianne Feinstein (D-Calif.), who recently won approval of legislation requiring the installation of automatic train-stopping systems on Metrolink and other rail services by 2015, also is questioning the strategy.

"I find it hard to understand how adding cameras instead of extra engineers is a more effective way to increase passenger safety on Metrolink," she said.

"Candidly, I don't understand how an inanimate object like a camera protects against a crash. A camera can't speak out. It can't pull a lever. It can't stop the train. It can't take any action."

Live video recently was endorsed by a panel of safety experts after a two-month review of Metrolink operations.

Indeed, part of the thinking is that video cameras can eliminate the need for a second crew member in locomotives, a "second set of eyes" precaution that Metrolink officials added to several lines after the Chatsworth accident.

Some research has found that a second crew member can create distractions and actually contribute to accidents.

One important benefit of video and voice recordings is to understand and prevent accidents, said Mark V. Rosenker, acting chairman of the National Transportation Safety Board, which is leading a multi-agency inquiry into the Chatsworth collision.

For years, the NTSB has called for crash-proof voice recorders on trains, although Metrolink and many other rail lines don't have them.

Now, the agency is urging federal rail regulators to consider making it mandatory for rail lines to install hardened recorders that can capture video and sounds.

"I think video in the cab clearly would have been a valuable tool" in the Chatsworth probe, Rosenker said. "A whole host of information . . . would have been on the tape. It would have been a factual [record] of what the engineer was doing and not doing."