A test-rig for measuring three-piece bogie dynamic parameters applied to a freight car application

The warp stiffness is an inherent dynamic parameter of a three-piece bogie; it is not present until a bogie is constructed and its value varies with the bogie status. The methodology for accurately measuring the warp stiffness is important for evaluating the dynamic performance of a freight car with a three-piece bogie. This paper describes a test-rig for measuring warp stiffness and other dynamic parameters relating to the three-piece bogie. The test-rig is composed of a sliding plate with a hydraulic servo-mechanism for applying forces and a measurement system based on virtual instrument technology. The process of measuring warp stiffness on this rig-test is presented in detail. Finally, the application of this test-rig is described and some results such as the warp stiffness of K1 and Z8A bogies are described in the paper.