The Massachusetts Bay Transportation Authority was its department within the Commonwealth of Massachusetts before becoming a division of MassDOT in 2009 .
The MTA was replaced in 1964 with the present-day MBTA , which was established as an individual department within the Commonwealth of Massachusetts before becoming a division of the Massachusetts Department of Transportation ( MassDOT ) in 2009.The MBTA and Philadelphia 's Southeastern Pennsylvania Transportation Authority ( SEPTA ) are the only U.S. transit agencies that operate all five major types of terrestrial mass transit vehicles : light rail vehicles ( the Ashmont–Mattapan High Speed and Green Lines ) ; heavy rail trains ( the Blue , Orange , and Red Lines ) ; regional rail trains ( the Commuter Rail ) ; electric trolleybuses ( the Silver Line ) ; and motor buses ( MBTA Bus ) .
Massachusetts Bay Transportation Authority