Case Study: TrueProfile™

Railroad wheels wear, just as do tires, and a badly worn wheel is an inefficient and potentially dangerous wheel. Wheels must be inspected, but it is effectively impossible to inspect each and every wheel as frequently as might be desirable; there are literally millions of wheels in service. Ideally, a wheel would be inspected every time it passed through a railyard where – if it was no longer fit for service – it could be immediately brought to a shop and re-trued or replaced.

IEM undertook to develop precisely this system, starting with the experience gained from our design and marketing of our portable Electronic Wheel Gauge. The problem was simple to state: how can a wheel be accurately measured in all dimensions while in motion?

The obvious answer was an in-ground system over or through which the wheels would pass and be measured. To prevent wear and tear, the measurement also had to be non-contact and of significant standoff, otherwise the mechanism would be too close to the moving train components. Based on these points, IEM proposed the development of a structured-light based measurement approach. Initial research was funded by the Federal government’s SBIR program and later by the Transportation Research Board, resulting in a prototype system tested at AMTRAK. The New York State Energy Research and Development Authority also supported this work, resulting in the development of our TrueProfile™ technology.


Now in use in multiple sites in several countries, TrueProfile™ applies patented methods (5,636,026 and 6,768,551) to use projected laser light to outline the wheel from both sides and acquires images from precisely controlled locations to determine the dimensions of the wheel to a precision greater than that available from any handheld gauge. The system can be installed as individual instrument bays or installed as a unit in our patent-pending Integrated Tiebox (ITB) design.