Interface - The Journal of Wheel/Rail Interaction

EDITORIAL

Managing the Basics
January, 2010

Managing the wheel/rail interface is a complex process. Procedures such as rail grinding are required to maintain the desired rail profile shape — an essential component of wheel/rail interaction.

Rail grinding has been shown to effectively control rail surface conditions by removing corrugation, plastic deformation and rolling contact fatigue cracks that can reduce the service life of rail. Coupled with an effective friction management program, rail grinding can effectively double the life of rail in track. Grinding can also help to manage vehicle steering forces that affect vehicle/track performance and component life. Grinding cannot, however, correct all track ills.

"Grinding will not compensate for wide gauge, or correct tipped rail," Norm Hooper points out in "Successful Grinding: Starting with the Basics."

"In fact," he says, "profile grinding tipped rail can cause serious steering problems if the rail is re-set to the proper cant without an immediate re-grind. Grinding also will not improve the ride quality, if the track has poor crosslevel or alignment."

Hooper considers some of the "truths" about track and maintenance procedures, and provides recommendations on how Maintenance Departments can make the most of grinding and other maintenance procedures.

Automated Wheel/Rail Contact Inspection
In order to effectively manage the interface, wheel/rail profiles and contact conditions must be measured and analyzed.

The Transportation Technology Center, Inc., (TTCI) has developed an automated Wheel/Rail Contact Inspection (WRCI™) system, which performs real-time assessment of wheel/rail contact conditions, comparing measured rail profiles to wheel profiles that are drawn from cars that normally travel over the route being inspected.

The TTCI’s Huimin Wu and Semih Kalay explain how the (WRCI™) system predicts the effects of wheel/rail contact on vehicle performance and determines the need for rail reprofiling in Parts 1 and 2 of "Management of the Wheel/Rail Contact Interface in Heavy-Haul Operations."

Wear and rolling contact fatigue of rails and wheels are common problems under heavy-haul operations. "Increasing axle loads can increase the capacity of a railway system, but also can increase the stress state of the system," the authors point out. "Reducing the energy input into the wheel/rail interface is a key strategy to reducing wear and RCF."

Primary elements of the wheel/rail interface management technique are:
• Development of an automated wheel/rail contact inspection system for conducting system-wide wheel/rail contact inspection.
• Identification of undesired wheel/rail contact conditions causing vehicle performance problems and excessive wear and RCF on both wheels and rails.
• Guidance for wheel and track maintenance to correct the identified wheel/rail contact problems.

While analysis is currently based primarily on wheel/rail profile geometries and static wheel loads, further development will include creepage and dynamic wheel/rail forces from a large population of cars with varying performance characteristics in order to quantitatively assess rail wear and the initiation of RCF.

This technique of managing wheel/rail contact will be implemented on track geometry inspection cars, ensuring that both track geometry and wheel/rail contact conditions will be inspected at regular intervals. With this, a more complete evaluation of track conditions can be used to determine the need and priority for rail maintenance.

Enjoy the issue.

Bob Tuzik
Publisher