Technology Digests / Analysis of Asymmetric Hollow Worn Wheels

TD22-026

October 1, 2022
Authors
  • Ulrich Spangenberg
  • Kenny Morrison
  • Scott Cummings
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Key Findings

  • Asymmetric hollow wear is not caused by initial diameter difference of mate wheels within the allowable variation of the same tape size.
  • The tape size matching required by AAR Standard S-659 does not result in unacceptable asymmetric hollow wear performance.
  • Asymmetric hollow wear develops more frequently on intermodal and vehicular flat railcar types (AAR types Q, S, and V).
  • Asymmetric hollow wear does not cause a greater angle of attack, but results in a lateral offset of the wheelset relative to the center of tangent track.
  • The difference in hollow wear of mate wheels is related to a difference in hollow wear location and a difference in flange wear.
  • Hollow wear of an individual wheel is not strongly related or dependent on any other wear parameter of that wheel.

Analysis of Asymmetric Hollow Worn Wheels

As part of the Association of American Railroads’ (AAR) Wheel/Rail Profile Design and Maintenance Strategic Research Initiatives project, MxV Rail (formerly TTCI) investigated the formation of hollow worn wheels in an effort to reduce asymmetric hollow wear (i.e., the development of a substantial difference in hollowing between the two wheels of a single wheelset). Wheels with excessive hollow wear are a cause for removal according to AAR Field Manual of Interchange Rules, Rule 41.A.1.ab and Rule 41.A.2.b.1 MxV Rail researchers conducted a study of worn wheel profiles and wheel wear data from wayside wheel profile detector (WPD) systems to understand the development of hollow worn wheels. In addition, the team studied wheelset assembly practices, hollow wear prevalence on given railcar types, and the wheelset on-track performance. Figure 1.Definition of hollow wear and hollow wear position INTRODUCTION Hollow wear is a typical and anticipated form of wheel…