Even a tiny shift in the angle at which wheels meet the rail – the “angle of attack” – can cause significant increases in wheel and rail wear, waste significant amounts of energy due to the wheel in effect being dragged somewhat sideways, and degrade ride quality for passenger services. Greater divergences in angle of attack can lead to greater damage and possibly even derailments. Other distortions of wheel, truck, axle or even rail can cause other problems with similar results, such as truck “hunting” on the rail. Detecting these divergences has been historically difficult to manage, and only possible in carefully controlled low-speed settings. A few recent systems have attempted to resolve the problem with laser-based metrology, but have met with limited success for a number of reasons.

IEM’s patent-pending Track-Wheel Geometry Measurement System provides a solution. Derived from over fifteen years of experience in patented and patent-pending structured-light measurement of rail systems, the Truck Performance and Hunting Detection System uses multiple methods to provide a clear absolute frame of reference for the wheel-rail system, thus allowing all aspects of the wheel’s relationship to the rail – in all three angular axes – to be accurately measured, at speeds exceeding 100mph (160kph). Several such installations in close proximity can detect active behavior such as hunting as well as static characteristics such as a misaligned truck/axle.