LATERAL STABILITY ANALYSIS OF A RAILWAY TRUCK ON ROLLER RIG

Generic linear models were developed of a freight car (with a characte ristic North American three-piece truck) on tangent track. The models were developed using the generalized multi-body dynamics software MEDY NA. Predictions were made of the theoretical linear model hunting (lat eral stability) characteristics of the freight car, i.e., the critical speeds and frequencies, for five different configurations: (a) freigh t car on track, (b) the freight car's front truck on the roller stand and its rear truck on track, (c) freight car on the roller rig, (d) a single truck on track and (e) single truck on the roller stand. These were compared with the Association of American Railroads' field test d ata for an 80-ton hopper car equipped with A-3 ride control trucks. Ag reement was reached among all the analytical models, with all models i ndicating a range of hunting speeds of 2% from the highest to lowest. The largest discrepancy, approximately 8%, was indicated between the m odels and the field test data.