Investigation of Hunting Phenomenon for High Speed Railway Vehicles Considering Wheel Flange Repulsion Against Rail

During a high speed running test of an actual car of the SHINKANSEN conducted by the Japanese National Railways, a severe truck hunting having a high frequency and a very short wavelength began to occur at a speed of about 180 km/h. It is already known that the main reasons for such a truck hunting are, among others, large clearances of the connecting positions between the truck frame and the bolster anchors, and inadequacy of the supporting stiffness of axles. Taking into account these facts, the authors made a theoretical analysis of the hunting stability of a one-half car model which is an eight-degrees-freedom system. In the analytical calculation, the repulsion of the rail against the wheel flange, the variation of wheel tread conicity due to geometrical contact between the wheel and the rail were taken into account. Consequently, in this basic investigation, truck hunting, which has been an unsolved phenomenon, is now clarified and its preventing method has been established.