South Station underground concourse and Red Line connection

South Station is Boston's primary intermodal rail terminal and contains underground concourses and platforms that connect the main headhouse to the Red Line subway and to commuter rail and intercity bus facilities. The Red Line's South Station platforms are located below the main station concourse and provide direct underground transfers to the commuter rail and bus terminal areas. South Station's subterranean passages are a major node in the city's transit network.