Massachusetts Bay Transportation Authority

The Massachusetts Bay Transportation Authority (abbreviated MBTA and known colloquially as "the T") is the public agency responsible for operating most public transportation services in Greater Boston, Massachusetts. The MBTA transit network includes the MBTA subway with three metro lines (the Blue, Orange, and Red lines), two light rail lines (the Green and Mattapan lines), and a five-line bus rapid transit system (the Silver Line); MBTA bus local and express service; the twelve-line MBTA Commuter Rail system, and several ferry routes.

Source: Wikipedia — Massachusetts Bay Transportation Authority (CC BY-SA 4.0)