Abstract: A stairway wheelchair lift includes a stationary motor drive unit, a rail assembly extending along the stairway and a mobile platform movable along the rail. A flexible drive member, such as a chain or cable, within the rail assembly, is driven by the motor drive unit and is connected to the mobile platform to move the platform in either direction along the rail. The mobile platform is adapted to support and transport a wheelchair-bound passenger during use, and to fold upwardly out of the way of the stairway when the lift is not in use. An automatically actuated brake mechanism stops further movement of the mobile platform when the speed of the platform relative to the rail exceeds a predetermined threshold, and a plurality of safety sensing switches prevent operation of the lift in the presence of obstructions along the stairway or other unsafe conditions.