Laboratory dynamic deformation (warp) testing of freight car trucks

Within the context of improved truck design in general and addressing double stack service problems in particular, American Steel Foundries (ASF) has developed a test fixture at their Test Engineering Center for determining the mechanical deformation characteristics of freight car trucks undergoing various modes of motion approximately constrained to the horizontal plane. These motions include distortions of the nominal squared geometry to produce a parallelogrammed geometry (referred to as warp) and a rigid body angular motion that produces a rotated configuration. A review of the capabilities at the ASF truck deformation testing fixture is given. A discussion of the types of tests that are performed, the data parameters that are acquired, and the type of analysis that is performed is presented. A brief examination of test results from two contrasting types of freight car trucks-one conventional and one very stiff-is given. Some suggestions regarding future investigation are presented