Haymarket is an MBTA subway station serving the Green and Orange lines, located at the corner of Congress and New Sudbury streets in downtown Boston, Massachusetts. Haymarket allows transfers between the Orange and Green lines, as does North Station one stop to the north. Haymarket was named for Haymarket Square, which has served as a produce market since around 1830.Unusually, the two subway lines that converge at Haymarket are not stacked vertically underground, but instead are parallel at approximately the same level. The Orange Line access consists of two side platforms to serve the line's two tracks, while the Green Line is served by a single island platform which is divided mostly in half by a wall. Passenger transfers between lines require changing levels via stairs or elevator, so it may be preferable to transfer at more-spacious North Station, which also allows convenient cross-platform transfers for inbound trips.The station is fully wheelchair accessible.HistoryTremont Street SubwayThe Tremont Street Subway (future Green Line), including Haymarket, was built starting in 1894 and opened on September 3, 1898. The original trolley station was much more spacious than the current station, and consisted of four tracks with a pair of island platforms. The inner pair of tracks served cars from the northern suburbs which turned at Brattle Loop at Scollay Square (now Government Center) station, while the outer tracks served streetcars that ran through the entire Tremont Street Subway to the Public Gardens Portal and Pleasant Street Portal. All cars entered the subway through the Canal Street Incline just north of Haymarket.