Massachusetts on Wednesday banned drivers of trains, street cars and buses from using or even carrying cell phones at work, the toughest such measure imposed by a U.S. state transit agency.

Any driver working for the Massachusetts Bay Transportation Authority caught talking or text-messaging on a cell phone or similar device will be suspended for a month and managers will recommend their dismissal, the state said.

Drivers found carrying their phones on duty face a 10-day suspension for a first offense. If it happens again, they will be suspended for a month and face a dismissal recommendation.

The tough new rules were imposed after two trolleys collided in a Boston tunnel on Friday, injuring 49 people, when one of the drivers failed to stop. He told authorities later he was sending a text message to his girlfriend at the time.

I know what I saw on Friday night in that tunnel. I know what the cause was. And I know that this new policy would have prevented it, said Daniel Grabauskas, general manager of the Massachusetts Bay Transportation Authority.

The National Safety Council, an independent, nonprofit group, said the rules were the most stringent of any U.S. state transit authority.

I predict what we do here in Massachusetts today will soon become a national model, Massachusetts Transportation Secretary James Aloisi told a news conference.

Massachusetts had already banned state transit operators from using cell phones. The new, tougher rules take effect on Monday.

The transit authority set up a hotline service in case a driver needs to be contacted by family in an emergency.

(Reporting by Jason Szep; Editing by Helen Popper)