Wheel shelling is a phenomenon that is well known to North American rail operators, and is a form of rolling contact fatigue (RCF) damage. RCF damage occurs when the wheel steel is overstressed. The damage occurs in the form of cracks that initiate at or below the wheel tread surface. These cracks grow and branch together under the surface until the steel above them no longer has sufficient strength to bear the imposed loads. The surface steel can then fall out of the wheel, revealing a shell which has the appearance of a small and shallow crater in the tread's surface.
Shelled wheels impose high dynamic loads on the rails, which can increase the risk of rail failure. The regulators of the North American railway industry have rules that determine when a shelled wheel must be removed from service, to manage the risk of rail failure. The rules include visual assessment of wheels by trained inspectors at terminals, but the railways have also invested heavily in permanently installed trackside monitoring systems that measure the dynamic loads of all wheels on trains as they run along the track. This enables railways to not only "catch" wheels that have shelled to undesirable levels in between terminals, but to use predictive algorithms to schedule rail cars for preventive wheel maintenance.
Despite advances in technology, wheel shelling continues to be a logistical and economic problem. Railways affected by cold temperatures in particular are known to suffer much greater rates in the winter months compared to the rest of the year. This seriously affects rail car availability because car repair shops become overwhelmed with change-outs for shelled wheelsets and with maintaining a winter stockpile of wheels. As well, many shelled wheelsets are scrapped prematurely even though there is still a lot of wearable metal left on the tread.
What is RailWheelS?
The RailWheelS industrial R&D group is an NRC-led research initiative to develop innovative technological solutions to seasonal railway wheel shelling issues. The NRC and RailWheelS R&D group members share benefits, risks and costs associated with large-scale R&D activities that aim to reduce the costs associated with wheel shelling and improve railway safety. The NRC is leveraging its research experience and unique research facilities to develop ways to reduce wheel shelling's impact on railways affected by cold climates.
- VIA Rail
- Quebec North Shore and Labrador Railway Company Inc. (QNS&L)
- TTX Company
- ArcelorMittal Infrastructure Canada
- L.B. Foster Company
Currently accepting new membership applications to RailWheelS.
Why join RailWheelS?
- Identify root cause(s) of wheel shelling as a function of wheel type, wheel longevity, operating environment or other factors that will be determined through the review and research processes
- Access to large-budget research project results at a fraction of the cost
- Competitive advantage: research results and potential solutions are only shared with RailWheelS members. All R&D group members have access to the same research results and conclusions
- Sharing of research ideas within a collaborative group allows more meaningful definition of the shelling problem and practical mitigation strategies for members
- Comprehensive, reliable research performed by Canada's leading scientific research and development organization
How does RailWheelS work?
- The RailWheelS structure uses an unbiased scientific approach to the wheel shelling problem. The R&D group fosters collaboration and discussion among members to streamline implementation of solutions in member operations
- Projects are focussed on addressing issues identified by members, based on their needs. This approach facilitates effective transition of research results into member operations
The RailWheelS Industrial R&D Group is currently accepting new members. For more information on how to become a member, please contact:
North American freight Class 1s, short lines, long-distance passenger service providers, railway suppliers and service providers that experience business disruptions or incur significant costs due to seasonal wheel shelling defects.