Allan Zarembski
University of Delaware
Brad Kerchof
Norfolk Southern
Abstract:
Wheel Climb Risk at Turnouts
Most wheel climb derailments at switch points are caused by a combination of a worn switch point and a worn wheel. And while the mechanical department has a number of AAR-approved gauges to evaluate wheel profile compliance, there is precious little guidance provided by industry or government for identifying high-risk switch points. Railroad territories that have few switch point derailments benefit from skilled switch inspectors, who likely acquired their knowledge through experience – by seeing first-hand which switch point profiles caused derailments. This is a costly way to develop a switch inspector. Recognizing a deficiency in inspector education as well as a significant opportunity to improve track safety, the University of Delaware Railway Engineering Department submitted a successful switch inspection research proposal to the TRB’s Safety IDEA Committee.
The project team, which included rail industry partners, began by identifying switch point inspection practices used by two European railroads. The team found that these railroads employed a number of gauges that identified undesirable wheel flange contact and assessed switch point shape and stock rail fit. Concluding that these gauges greatly enhanced the effectiveness of switch point inspection, the team replicated four of the gauges and tested them on worn points in a US rail yard. While two of the gauges were judged ineffective, two were recognized as offering real value in identifying wheel-climb risk. After several modification and test iterations, three gages were selected for further study, including a gauge that reflected the climbing potential of a worn wheel.
In the project’s second phase, the team will complete the development of a set of gauges that will identify high-risk switch points, confirm industry acceptance of the gauges through field testing on several railroads, and promote their use as an aid to switch inspection.