The MBTA Commuter Rail is the regional rail arm of the Massachusetts Bay Transportation Authority, in the Unite States. The line's characteristic purple-trimmed coaches run as far south as Providence, Rhode Island, and as far north as Newburyport and as far west as Worcester, both in Massachusetts. Because of this coloring, locals often call the system the Purple Line, to match the names of the colored subway lines. The trains have two terminal stops in Boston—South Station and North Station—both linked with Amtrak and the local bus and subway lines. (See "Boston transportation".)