BOSTON -- The Massachusetts Bay Transportation Authority is poised to announce major safety changes Wednesday in the wake of last week's Green Line trolley crash.

NewsCenter 5's Gail Huff reported that the MBTA is expected to issue a total ban on all cell phones for drivers while they're on the job. They're already prohibited from using them while working and the new rule may ban them from even having them in their possession while on the clock. It may be a first-of-its-kind ban on cell phone possession for public transit drivers.

The MBTA's Carmen's Union appears to support the move.

"MBTA drivers should be held to a very high standard," Carmen's Union president Stephen MacDougall said.

The union argued that Friday's Green Line crash and last year's fatal collision in Newton, could have been prevented.

"If there was a true committment to safety, we would not be running the Green Line on an antiquated signal system," MacDougall said.

The union is pushing for automatic fail-safe switches that would keep trains from getting too close to one another.

"How many more accidents have to occur before the T will make this appropriate investment?" MacDougall said.

The MBTA, however, said the switches are costly and impractical and said mechanical failure was ruled out in Friday's crash after the trolley operator, Aiden Quinn, 24, admitted he was texting while driving.

"I think we're back to operator error and we've already got an operator who's admitted that they were texting," MBTA chief Dan Grabauskas said.

In the wake of the accident, there is a renewed call on Beacon Hill to review safety policies for all of the state's 16 transit authorities.

Some lawmakers want to ban all bus, trolley and train operators from carrying cell phones on the job, across the entire state.

"I've often said that you can't legislate common sense, but I'm getting to the point where I think in some of these cases, with younger folks, we need to," State Senate Transportation Committee Chairman Stephen Baddour said.

"I think it would be appropriate to have a ban on people who are driving other people around from losing their attention span. Especially driving commercial vehicles," State Sen. Stephen Brewer said.

Gov. Deval Patrick said he was "outraged" by the crash and called for a complete review of the transit agency's hiring and training policies.

Patrick said the T should reconsider its minimum age of 18 for operators.

The Democrat said even though his daughters, ages 23 and 19, are responsible, he is not sure he would want them driving a trolley.

Meanwhile, Quinn's lawyer released a statement that said, in part, "Aiden is extremely remorseful about the accident which occurred on the T last Friday ... He is scheduled to have surgery on his shattered wrist later this week."

He is staying with his mother at her Quincy home and has missed two meetings with federal investigators and MBTA officials. He has been ordered to meet with his superiors on Friday.