Non-Destructive Testing of Plastic and Composite Ties

This article describes a non-destructive testing process to inspect the integrity of plastic railroad ties, which are being manufactured and installed by a number of railroads. Plastic and composite ties are less susceptible to decay than wood ties. One supplier of plastic ties developed the testing process, which utilizes x-rays to search for voids or internal defects inside the ties it manufactures. An internal software process determines if the tie should be rejected. Those ties that were rejected were shipped to the Transportation Technology Center where standard bending tests were conducted to determine if the voids affected strength and stiffness of the ties. This series of tests was part of a preliminary investigation. Additional evaluations are planned.