MODELING AND SIMULATION OF THE HUNTING OF A 3-PIECE RAILWAY TRUCK ON NRC CURVED TRACK SIMULATOR

Generic linear models were developed of a freight car (with a characte ristic North American three-piece truck) on tangent track and on NRC's Curved Track Simulator (CTS). The models were developed using the gen eralized multi body dynamics software MEDYNA. Predictions were made of the theoretical linear model hunting (lateral stability) characterist ics of the freight car, i.e., the critical speeds and frequencies, for five different configurations: (a) freight car on track, (b) the frei ght car's front truck on the CTS and its rear truck on track, (c) frei ght car on the CTS, (d) a single truck on track, and (e) single truck on the CTS. These were compared with the Association of American Railr oads' field test data for an 80-ton hopper car equipped with A-3 ride control trucks. Good agreement was achieved among all the analytical m odels, with all the models indicating a range of hunting speeds of 2% from the highest to lowest. The largest discrepancy, approximately 6%, was indicated between the models and the field test data.