both platform types. For on-street stations, stairs are deployed within the vehicle to allow boarding from low platforms; as the trains move underground, the stairs rise until they are flush with the floor to allow boarding from high platforms. See also List of buses Low floor Low-floor bus Low-floor tram Railway platform height Street running Tram stop References External links This article is based upon a translation of the German language version as at August 2011. Passenger rail transport Tram vehicles Buses by type