Railway Track & Structures - February 2008 - (Page 23) shelling will block any ultrasonic energy from being transmitted past the area of delaminating steel. With our new search unit, we have optimized the transducer placement to project sound energy underneath the shelling to detect transverse elements that otherwise might be masked. To date, field testing has been successful with the new array and we are moving forward to place the new search units on areas with higher tonnage where defects of this nature are most likely to develop.” Elbert also pointed out another method of detecting this type of defect by using the rail as a “waveguide” to search for discontinuities or deviations from a normal return. “This occurs when an ultrasonic wave is transmitted into the steel and relayed longitudinally over a given distance. Since defects will effectively block an ultrasonic wave, the absent or diminished waveform could be an indicator of a defective section of rail,” said Elbert. “Herzog Services, Inc., has been actively involved in a project in conjunction with TTCI to help develop a test vehicle that utilizes laser-induced ultrasonic waves that utilize ‘waveguide’ technology in a non-contact fashion. We have also explored the possibility of utilizing the rail as a waveguide with conventionally-induced ultrasonic waves (the probes are in contact with the rail surface) to detect base defects, another concern posed by our customers. In an experiment, several EDM notches were placed in a test rail at our facility to simulate base cracks at the outside edges. Although the detection unit successfully detected the notches, other variables need to be added into the Dapco rail inspection vehicle on track looking for flaws. system to continue the research.” Elbert notes that, as always, Herzog Services strives to make the test system as user friendly and accurate as possible and 2008 will be no different when it comes to discussing software and hardware revisions to exploit newer and faster technologies. “Our team of engineers is continually looking at new alternatives with software languages and hardware options to improve our product, making it smaller, lighter and more powerful. An ongoing project within our group is to analyze feedback on our pattern recognition system and refining the algorithms to increase the accuracy of the system beyond current capabilities. Other projects include a complete revision of the acquisition hardware to take advantage of faster signal processors. We have also initiated a program with a major Class 1 railroad to provide them with daily Geographic Information System (GIS) uploads using GPS points automatically accumulated during an inspection. These uploads are used to verify existing track and also to initiate recording the GIS locations of unmapped and new track construction,” said Elbert. “Through all our efforts, the ultimate goal, of course, is to provide the operators and customers with the best tools available to do the job and to provide a consistent, quality service.” www.rtands.com Railway Track & Structures February 2008 23 http://www.ensco.com/trans http://www.ensco.com/trans http://www.rtands.com
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