Central subway (Boston)

Boston's central subway is the system of tunnels through which the MBTA Green Line operates light rail transit (LRT or "trolley") service in the urban core of the city.

Boston's subway operator, the MBTA, sometimes also refers to the Red Line and Orange Line heavy rail tunnels as part of the central subway tunnel.

[4][5][6] The original vehicles used were early single-unit electric trams with trolley poles to pick up the electric power from an overhead wire, which Boston had a decade of experience with.

[7] Frank Sprague introduced electric multiple unit (EMU) trains in Chicago, also in 1897, and those came to Boston a few years later, not in the trolley subway but in the new "elevated", the Boston Elevated Railway (BERy), which mostly served the West End.

By 1901, Boston had the first EMU trains running underground, using some of the tracks and modified platforms of the Tremont Street subway.