ABSTRACT
Generic linear models were developed of a freight car (with a characteristic North American three-piece truck) on tangent track and on NRC’s Curved Track Simulator (CTS). The models were developed using the generalized multi body dynamics software MEDYNA.
Predictions were made of the theoretical linear model hunting (lateral stability) characteristics of the freight car, i.e., the critical speeds and frequencies, for five different configurations: (a) freight car on track, (b) the freight car’s front truck on the CTS and its rear truck on track, (c) freight 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 Railroads’ field test data for an 80-ton hopper car equipped with A-3 ride control trucks.
Good agreement was achieved among all the analytical models, 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.
