The MBTA said today it is firing the driver responsible for a collision at Boylston station last week that sent three dozen people to the hospital with minor injuries and caused $500,000 in damage to trolleys.

Acting MBTA General Manager Jonathan Davis said the driver told investigators he had come off a midnight-to-8 a.m. shift at another job when he started his first run of the day on the Green Line at 11 a.m. - about 45 minutes before the collision at Boylston.

Davis said he could not say if the driver, who had been driving for the T full time, fell asleep but that he was clearly "inattentive" when he ran his train into a stopped train at the station. He said the T's investigation had ruled out any physical problems with the tracks or trolleys and that the driver admitted everything seemed to be working fine in the moments before the collision.

Davis said the T has no policy against second jobs or requirements that workers inform managers about second jobs, but that drivers are expected to be fully alert while driving trains - and that the three-hour gap between the end of his second job and the start of his first run on the Green Line did not leave the driver enough time to get adequate sleep.

He declined to name the driver and the location and nature of the second job.