Park Street is a subway station on the MBTA subway system, located at the intersection of Park Street and Tremont Street under Boston Common in downtown Boston. One of the four subway hub stations — and one of the two oldest stations on the "T", the other being Boylston — Park Street is a transfer point between the Green and Red Lines. Park Street is the fourth-busiest station in the MBTA network, with an average of 19,836 entries each weekday in 2010. Throughout the Green and Red Lines, trains labeled "inbound" are headed towards this station, Downtown Crossing, or Government Center, while those labeled "outbound" are headed away.