The MBTA trolley operator who investigators said was text messaging his girlfriend before a crash in Boston last week has been fired.

The transit system said General Manager Daniel Grabauskas notified the trolley operator, Aiden Quinn, on Thursday that he had been discharged.

About 50 people were hurt when the Green Line trolley that Quinn was operating rear-ended another train between the Government Center and Park Street stations last Friday.

Quinn, 24, from Attleboro, Mass., was a two-year employee of the MBTA. He had skipped meetings with MBTA and federal investigators since the crash, saying he was not feeling well, MyFOXBoston.com reported Thursday.

Also Thursday, the MBTA's main labor union reversed course and decided to challenge the transit agency's new ban on the possession or use of cell phones while working.

The Boston Carmen's Union said in a letter Thursday that "the rule is unreasonable under the contract" with subway and trolley drivers. The members said they support some change in policy, but only after it has been negotiated.

Under the new policy, operators caught talking or text-messaging on a cell phone will be discharged immediately.

There will be a 10-day suspension for a first offense of carrying a phone or PDA. A second offense will be punished by a 30-day suspension with recommendation for firing.

The policy change announced Wednesday is the strictest in the nation. The state already bans transit operators from using cell phones while they're on the job.

Transportation Secretary James Aloisi says the policy is designed to avoid a repeat of "the error of judgment" that led to Friday's accident.

ABC News had cited a transit source who said Quinn was hired as a minority because of his transgender status, but the Massachusetts Bay Transportation Authority refuted that claim, saying there was "nothing unusual" in his hiring and that he was picked out of a hiring lottery in 2004.

Quinn may face criminal charges for his role in the crash, which occurred when his car ran a red light. Some passengers had to be taken away on stretchers. Quinn suffered a broken wrist.

Damages from the accident are expected to top $9 million dollars, according to the MBTA.

Click here for more on this story from MyFOXBoston.com.

The Associated Press contributed to this report.