effects of the longitudinal and lateral axlebox clearance on hunting, curving and wear behavior of the three piece bogies

three piece bogies are widely in use by the freight railway services throughout the world. in comparison with the other freight bogies they cost less and are easier to maintain. however, they do not exhibit favorable curving behavior. amongst the methods to improve the bogie performance is the proposal to introduce lateral clearance in the bogies’ axleboxs. in the case of the three piece bogies, the lateral clearance has been used by some of the practicing engineers. it obviously added to the non-linear effects in the bogie tribological system and its dynamic performance. this study includes simulating the effects of the axlebox lateral clearance on hunting and curving behavior of the three pieces bogies. the effects of lubricating the rails at curves and adding to the track gauge are also investigated. the simulation is with the universal mechanism (um) engineering software. it involves a loaded freight wagon equipped with two three piece bogies of type 18-100. propositions are made in order to improve the vehicle dynamic performance and to decrease its maintenance costs.