The Federal Railroad Administration (FRA) co-sponsored Transportation Technology Center, Inc. (TTCI) on a trackwork inspection effort scheduled for completion in September 2022. This research demonstrated the potential for the low-frequency ultrasonic testing (UT) nondestructive evaluation (NDE) method to characterize internal flaws in crossing. First, TTCI fabricated a test sample from the crossing diamond that contained drilled holes (reflectors) at different depths. Second, microstructural analysis and microhardness measurements characterized its microstructural and material properties. And third, researchers applied a low-frequency UT method to detect the reflectors in the test sample.