Abstract:The antioverturning capacity of straddling monorail vehicle is significantly affected by the contact states of stabilizing wheels and guiding wheels with track beam. When one side stabilizing wheel on bogie leave the side surface of track beam, the antioverturning ability straddling monorail vehicle of will decrease significantly. The overturning equations of straddling monorail vehicle are established and the formula of flexibility coefficient is deduced, and the influence of the contact state between the stabilizing wheels and guiding wheels and the track on the height of buoyancy centre and flexibility coefficient is analyzed. The critical roll angle is proposed to evaluated the change of antioverturning capacity of straddling monorail vehicle, and the formula of critical roll angel is derived and verified by UM software simulation. The reasonable value of prepressure on stabilizing wheel is discussed according to critical roll angle. When the preload pressure of the stabilizing wheels is determined, the maximum and minimum negotiation speeds at curves should be set to ensure dependable antioverturning capacity of the vehicles.