Interface - The Journal of Wheel/Rail Interaction

INTERFACE OPTIMIZATION

Tools and Techniques for Optimizing the Wheel/Rail Interface (continued)

MiniProf®, the first generation of digitized wheel profile measurement systems developed by Greenwood Engineering, changed all that. MiniProf captures a digital image of the wheel profile as a mechanical stylus is advanced across the tread surface and flange of the wheel (see Figure 4). Advances in laser technology have provided new options in digital wheel measurement.

Beena Vision and Rail Sciences Inc. developed LazerView, a hand-held laser profiling system that is attached by a magnetic fixture to the rim of the wheel (see Figure 5). The measurements, which have a resolution of 100 micrometers, are downloaded to a PDA device and are available for immediate comparison against selected AAR, Federal, or railroad maintenance standards. Figure 6 shows a screen shot of the captured profile and the key measurement standards. In addition to the accuracy of the digital measurement systems, an inspector using the LazerView measurement system, for example, can make the four key wheel measurements in half the time as an inspector using conventional wheel gauges.

In addition to hand-held digital measurement systems, automated in-track laser measurement systems have been introduced by railway systems around the world. These systems, which are installed in the ballast between ties or within hollow steel ties, are able to measure both wheels on a wheelset at track speed (see Figure 7).

Beena Vision’s WheelView system, which is marketed by Rail Sciences Inc., can measure and record parameters such as flange height, flange thickness, rim thickness and tread hollow at up to 65 mph with resolution of 0.05 mm, and repeatability of between 90% and 100% for multiple readings of the same wheel. Figure 8 shows an overlay from the database of a wheel profile to a new wheel.

The Massachusetts Bay Transportation Authority installed WheelScan, KLD Labs, Inc.’s automated laser measuring system, on the MBTA Green Line to monitor wheel profile conditions and to “flag” wheels that are at or approaching pre-set wear limits.

These and other types of automated in-track wheel measurement systems are being installed and tested on railways in North America, the U.K. and the Middle East, among others.

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