Track defects and the dynamic loads due to non-suspended masses of railway vehicles

Abstract

The motion of a railway vehicle on the rail running table is a forced oscillation with a forcing excitation (force), and damping expressed by a random, non-periodic function. The motion is described by formulas and it is illustrated through diagrams which have the form of a "signal". The railway vehicle has the Suspended (Sprung) and the Non Suspended (Unsprung) Masses. The track defects/ faults are the random excitation for the rolling wheels of the vehicle. In the case of the Sprung Masses of the vehicles, the forces resulting from the excitation (track defects) are not large and have small effect on the rolling of the wheel. In the case of the Unsprung Masses the forces resulting from the excitation (track defects) are large and have grate effect on the rolling of the wheel. The track, is simulated (with the observer situated on the wheel) as an elastic means with damping. The general equation that describes the problem is the second order differential equation of motion. In this paper the aforementioned equation is presented for the case of a railway vehicle rolling on a railway track and its solution is presented for the Unsprung (Non-Suspended) Masses of the vehicle that act directly on the track without the presence of any spring or damper.