Mohsen Dargazi - Head of rolling stock research group, Iran Railway Research Center
Reza Hatami - Technical Manager of Iran Railway Research Center
Zia Saadatnia - MSc. Student of Rolling Stock, School of railway engineering, Iran University of Science and Technology
Morad Shadfar - MSc. Student of Rolling Stock, School of railway engineering, Iran University of Science and Technology

Three pieces bogies are generally used for transporting heavy loads in vast countries. Stable dynamic behavior during operation, high velocity in straight lines, low initial cost and easy maintenance are the main advantages of these bogies. However, severe wear of wheels in curves, warping, high friction in center bowl and high un-sprung mass have created problems in operation. As the result of un-sprung masses, dynamic forces are noticeably increased and accelerate track deterioration and wheel damages. High friction forces in center bowl makes bogie tends warping and have high wheel wear rate. Different solutions have been presented to improve the performance of these bogies. However, none of these solutions could face and solve all of the problems mentioned. ZK1 bogie has been presented by designers to fix all the problems mentioned simultaneously. However the performance of this bogie in comparison with the three pieces one in the Iran railway network is still a question. In this paper by modeling of the ZK1 and three pieces bogies, considering nonlinear effects of friction wedges, dynamical performances of bogies are studied. The parameters are velocity and radius curvature and the effect of these parameters are examined on derailment and wear of the wheels and it is concluded that ZK1 plan is successful in performance improvement.

Three pieces bogie, ZK1 bogie, Dynamic Analysis, Derailment, Wear