A lightweight motorized and tracked sled for attachment to a variety of stair chairs is described. A power supply or power source provides power to a motor driving a track configured to engage a set of stairs. The motor and track can lift and support the stair chair and a patient thereon up or down one or more flights of stairs. The track driven by the motor has a length sufficient to simultaneously engage the lips or edges of a pair of sequential steps, but may be otherwise limited in length to reduce the weight of the track. To ensure that the sled and attached stair chair are stably supported while ascending or descending stairs, the sled may have rails, skis, or passive tracks having a length sufficient to ensure that the rails, skis, or passive tracks are always over the edge or lip of no fewer than two steps.