The purpose of this study is to explore the causes leading to the rail gouging from the perspective of armature dynamics. The axial, lateral motion and rotation equations were derived, and a set of calculations according to the experimental conditions were conducted. The calculated in-bore processes of the armature exhibit apparent non-linear features. Especially with the contact interface of armature being worn rapidly, the armature gradually leans toward one side of the bore, and forms a trend of oblique impact to the rail that may lead to the gouging. This study offered an insight on the transient processes of armature in bore, and helped to better understand the gouging failure mechanism.
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