Ensuring the safety of rolling stock movement when entering transition curves

Abstract

The main factor in the issue of the safety of the rolling stock movement in the rail track is the change in the magnitude of the lateral forces arising from the interaction of the wheel with the rail. The dynamics of changes in lateral forces directly depends on the increase in rolling stock speeds in curves and, especially, in transition curves. To prevent the sudden appearance of centrifugal force, the outer rail is elevated, the track is broadened when moving from a straight line to a circular curve and a transition curve of variable curvature r = l / p, where p is the variable radius of the curve. Within the transition curve, the current elevation h of the outer rail over the inner rail must be proportional to the current curvature value, including at the end of the transition curve, all these factors leading to a sharp dynamic increase in lateral forces. In this case, the elevation h0 of the rail and the curvature r0 = 1/R are the parameters of the circular curve. Due to the fact that r, h and track width S are variables within the transition curve, in case the widening in a circular curve is intended when moving along the transition curve, additional forces and moments arise not present either on a straight line or on a circular curve. It is necessary for any additional force factors (forces and moments) to change gradually and be equal to zero at the beginning (BTC) and end (ETC) of the transition curve, and for the absolute values and intensities (gradients) of their changes within the transition curve not to exceed the allowable values, which is provided by complying with the requirements specified in table.1.