Vibration Modes of a 70-Ton Boxcar

Vibration tests were performed on a 70-t boxcar both empty and fully loaded, with two packaging configurations. Nine vibration modes were identified: first roll, second roll, yaw, bounce, pitch, body torsion, body bending, and two lading modes. The effect of friction snubbing, gross weight, and amplitude of motion input at the rails was determined. Test results presented are a summary of modal frequencies, the deflections associated with each mode and the range of frequency variation.