Interface - The Journal of Wheel/Rail Interaction

EDITORIAL

Drawing a Technology Roadmap
April, 2009

This issue of Interface Journal looks at the industry’s ongoing efforts to manage wheel/rail interaction.

The Transportation Technology Center, Inc., long known for its research into the effects of operating heavy axle loads, has played an increasing role in examining wheel/rail interaction — measuring component wear, and vehicle and track performance. The results from a number of wheel/rail-related tests conducted in Class 1 revenue service and at the TTCI’s high tonnage loop in Pueblo, Colo., were covered during the Association of American Railroads / TTCI’s 14th Annual Research Review.

This month’s lead article, “Meeting the Industry’s Technology Goals,” provides coverage of the TTCI’s research into wheel/rail interaction, including the developing technology that can be used to measure it. The article also covers the benefits to be gained by being attentive to the wear and dynamic action that occurs.

“Understanding what’s going on at the wheel/rail interface moves us from reactive to proactive maintenance,” Lisa Stabler, BNSF’s Assistant Vice President for Quality and Reliability Engineering, told the railroaders, researchers and suppliers in attendance. She also pointed out that “unless there is a smoking gun, like a burned-off journal or a broken rail, a service failure is likely caused by an interaction.”

Contact Mechanics
Jude Igwemezie, President of Applied Rail Research Technologies Inc., provides a clinic on the fundamentals of contact mechanics, wheel and rail geometry and friction at the wheel/rail interface — an understanding of which can help rail managers prolong rail and wheel asset life. His article on “Understanding the Effects of Track Gauge, Wheel/Rail Geometry and Friction on Stresses at the Wheel/Rail Interface” also examines the role of lubrication and grinding to balance surface wear and the development of subsurface defects that occur when the rail is over-lubricated and there is not enough friction or wear.

With the appropriate level of friction, there is opportunity to wear away rail surface material that is damaged by contact fatigue, Igwemezie says. Too little friction (or too much lubrication) allows fatigue-related cracks that initiate at the rail surface to be driven “underground” to propagate beneath rail surface, where they are not visible or easily detectable.

“The challenge for rail operators is to find a balance between rail wear, acceptable depth of subsurface crack initiation, and risk of detail fractures and transverse defects that are not visible until it is too late,” he said. “The geometry of the wheel/rail contact and the friction between them becomes paramount.”

Performance-Based Tie Assessment
Also covered in this issue is the industry’s move toward the use of performance-based measurements to identify weak components and to plan the appropriate maintenance. As Robert Madderom, Vice President and General Manager of Holland LP, points out in “Using Performance-Based Assessment of Reserve Gauge Strength to Enhance Tie-Replacement Planning,” technology has changed the ways in which railroads plan most of their maintenance programs over the past 30 years.

“Modern technology is used to monitor track and component conditions in order to effectively plan and budget for maintenance requirements. Laser and optical systems are used to measure wheel and rail wear. Ultrasonic technologies can detect rail flaws before they mature,” Madderom says. But in 150 years of railroading, little has changed in terms of crosstie renewal. “Railways still select ties for replacement and plan a significant portion of their maintenance budgets based on visual inspections by walking tie inspectors.”

Gage Restraint Measurement Systems (GRMS) have been used to quantify the reserve track gauge strength — a key parameter in the selection of crossties for replacement or maintenance. “Gage Widening Projection,” which is derived from GRMS data, currently provides the best objective, performance-based measurement of the ability of ties and fasteners to hold gauge.

All signs point to the fact that technology, data and the information culled from it are moving the industry into an era of quantitative analysis of every day occurrences where the wheel meets the rail.

Enjoy the issue.

Bob Tuzik
Publisher