A railway steering system guided by a reference ahead of the train

Abstract

Modern-day bogies have reached a remarkable stage of sophistication, yet the dynamic stability of trains has to still contend with the ability of going through small radius curves. This paper addresses the dynamic characteristics of a guiding system that partially uses the lateral faces of the rails. Instead of hunting, typical of biconical axles, perturbations decay exponentially in straight sections of the track. In curves, the trains may exhibit an overturning tendency, like the Talgo train sets. The transfer function shows the absence of resonance and lower response to small wavelength perturbations. This means less stringent requirements about the radius of curvature and geometrical accuracy of the head of the rails and the thread of the wheels. A possible drawback is that these trains would only move forward in normal conditions (like automobiles) and not in both directions (like most trains). Another possible inconvenience is that these systems need some degree of automatic control.