A drive apparatus for boarding and unboarding devices, in particular for passenger doors, boarding ramps, retractable steps and the like on public transport vehicles having an electric drive motor the driven element of which is connected to the input element of a first reduction gear the output element of which is coupled to the actuation devices for the boarding and unboarding devices where the drive apparatus is constructed as a compact drive where the electric drive motor, the first reduction gear and a second reduction gear as well as an energizable clutch are disposed axially behind each other inside a tubular housing between the first reduction gear and the second reduction gear.