Speakers and Topics: Principles Course Sessions Abstract
Topic: Railroad Wheel Design Considerations, Service Defects and Failure Modes
Presenter: Cameron Lonsdale
Railroad wheels are key components that must not only guide the freight car or locomotive along the rails and support large mechanical loads, but also must withstand severe heating from tread braking. This presentation is designed to provide a broad general overview of factors that affect wheels in service, and to give attendees some background information on important metallurgical and manufacturing issues. First, a brief overview of railroad wheel history is provided. Next, wheel design, heat treatment, and manufacturing/quality considerations are discussed. Wheel profiles, contact stress, and current freight, passenger and locomotive wheel service issues are then reviewed. Significant attention is given to various service-related wheel defects (shelling, spalling, built-up-tread, slid flats, etc.) and to wheel failure modes such as vertical split rims (VSRs.), shattered rims, broken plates, etc. Recent research work into the development of axial residual tensile stress in the wheel rim while the wheel is in service, and the relationship of this axial stress to VSRs, is discussed. The development and testing of AAR Class D wheel steel, along with field testing on a major freight railroad, is described. Finally, additional recent research efforts to improve wheels are reviewed.