Abstract: The present invention is directed to a stairway chairlift system that includes a rail assembly mounted adjacent a wall along a stairway and further includes a motorized chair unit movable along rail assembly in ascending and descending directions along stairway. More particularly, the stairway chairlift system is normally powered from an Electric power supply 108. However, during AC power failure, the chair lift system automatically switches to battery power to enable chairlift 10 to run a number of trips after a power failure. After the power outage ends, the chairlift system automatically switches back to AC power supply for lift operations and the batteries are then recharged. Thus, if AC power is available, the batteries are not used or drained. Furthermore, the batteries are not continually charged and discharged as they are in a DC battery-operated system.