Stairway height adjustment is made by means of a hydraulic power pack. Stability is provided by four screw jack stabilizers, located on either side of the frame.The stairway chassis frame is constructed of steel tube, to which the step assemblies are attached. The stairway has a rigid axle with 4:00 x 8 solid rubber tires on the plane side, and swivel casters with solid rubber tires on the forward end of the stair. The ZT25TKT, Passenger Stairway is equipped with 2 stabilizer assemblies at the stair corners to stabilize the stairway and keep it locked in place. Stainless steel handrails give the passengers a solid structure to hold on to when boarding or deplaning. Illumination lights are located on the stairway and platform for easy nighttime boarding. Aluminum diamond plate provides a nonskid walking surface..