Nature of the Problem

IEM has worked with several Class 1 railroads to investigate alternative modes of wheel inspection that may be integrated with our WISE™ wheel inspection systems. One major concern expressed by IEM’s railroad customers focuses on a gap in current technology for effective detection, evaluation, and reporting of wheel flaws such as broken rims and flanges, rim rollover, and material accumulation on the tread adjacent to the flange. All of these conditions are external flaws that can significantly affect proper rolling efficiency of the wheels, which affects fuel efficiency, and are associated with derailments that cost the railroad industry millions of dollars every year.

IEM's WISE Solution

The problem of wheel flaw detection is certainly not new. Current methods employed by railroads focus on use of non-destructive ultrasonic methods. However, implementation of ultrasonics is expensive and requires development of special facilities and diversion of cars from freight service to a maintenance facility just to be evaluated. The railroad industry has expressed to IEM that their preferred approach would be evaluation of the wheels while the cars are in service. Even better, conducting this evaluation at a mainline supersite where various wheel measurements are already being conducted (such as found in IEM’s current WISE SuperSite™ high speed inspection system)  will enhance the usefulness of this inspection capability.

IEM has previously investigated alternative wheel flaw detection methodologies. IEM developed and demonstrated our EMAT-based wheel flaw detection technology (US Patent 6,523,411) that IEM later incorporated as an optional module in our Low Speed Humpyard WISE system . This system is limited to low speed measurement and detection of flaws such as cracks in the outer few millimeters of the wheel tread. IEM also investigated optical wheel flaw detection technology focused on low speed detection of flat spots and out of round wheels (US Patent 7,564,569).

Subsequently, IEM conducted a preliminary proof of concept study demonstrating that a variation of the patented optical approach developed for flat spot detection can be used to detect the types of damage railroads are concerned about. Most important, the approach does not suffer from the same susceptibilities to environmental conditions associated with current ultrasonic and EMAT technologies and can be adapted to work at mainline speeds typical of most supersite locations. Based on the past work and this feasibility evaluation, IEM is presently developing WISE Flaw™, an optical wheel flaw detection system that will specifically address the following goals:

• Ability to detect a variety of wheel flaws such as broken rims and flanges, rim rollover, material accretion on tread, spalling and shelling, and more
• Use of non-contact machine vision technology such as laser-based structured light
• Unaffected by environmental conditions such as electrical interference or adverse weather
• Able to operate from low to high speeds, with a target speed for effective operations of between 40 and 50 mph
• Able to evaluate operating trains and not require that cars be removed from service for evaluation
• Evaluates both field and gage side of wheels and detects flaws on wheel tread
• Integrates with IEM’s WISE SuperSite™ mainline wheel inspection system as well as IEM’s Low Speed WISE™ hump yard wheel inspection system enabling correlation of wheel flaw data with specific wheel sets on specific cars and ability to track flaws over time and provides a direct means for flagging a car for service.