A wagon–track dynamics interaction model has been developed to investigate the dynamics of suspensions with friction wedge dampers that are widely used in three-piece bogie wagons in Australia. The wagon is modelled using 66 degrees-of-freedom, accounting for the three-dimensional movements of all wagon components. The mass of the wedge has also been modelled. The track is modelled with rails as Timoshenko beams and discretely supported by the spring and damper elements representing the elasticity of pads, fasteners, and ballast. An assumed track geometry irregularity, i.e. top surface profile, is used for the analysis of suspension dynamics. The simulation results of the wagon–track dynamics interaction model have been compared with those from a VAMPIRE model. The VAMPIRE model uses the normal user level approaches without special subroutine development. Effects of the wedge friction conditions and the effect of track geometry irregularity have been investigated for the better understanding of dynamic performance of three-piece bogie suspensions.