Troy Elbert
Herzog Services, Inc.

Non-destructive methods for railroads have existed for quite some time, beginning with the percussion method, hitting the rail with a hammer and listening to the sound. From the times of the hammer, technology has evolved to include much more sophisticated and volumetric methods of inspection.

Electromagnetic inspection was first developed in the 1930s to find cracks in the rail before it could cause failure and catastrophic events, such as a derailment. This method proved to be useful, but it had low reliability. A more volumetric method, ultrasonic inspection, was introduced in the 1960s and has been the basis of rail inspection ever since. Over the years, the method has been improved with various applications of hardware, software, and advances in ultrasonic technology such as Phased Array Ultrasonic Testing (PAUT).

Providers of ultrasonic rail testing each have their own methods to build better solutions for identifying internal and external damage to rail. However, advanced computer algorithms and hardware are now making the inspection process more reliable and accurate. As we progress through the next phase of implementation, neural networks and artificial intelligence have the potential to analyze data quickly and yield efficiencies much higher than currently obtained. Coupled with Continuous Testing, and new processes that allow for delayed verification, we could be on the forefront of automated testing and multi-pass inspections.