Especially at high speeds, the hunting phenomenon of railway vehicles is one of the most important and fundamental problems from the view points of riding comfort and running safety and, therefore, many theoretical and experimental studies on this problem are being carried out for long time in various countries. The informations in wide scientific fields containing wheel/rail contact geometry are necessary for hunting analysis.

Recently, in particular from the vehicle maintainability point of view, positive use of profiled wheels is a matter of concern, and the need of analysing hunting phenomenon for this case is being more recognized. In this connection, it is required to make clear the contact geometry of the wheel/rail system having any cross-sectional profiles.

The main purposes of this study are; (1) to re-examine the expressions of the contact parameters of wheel/rail system having circular profiles which are indispensable to hunting analysis, (2) to develop more generalized linear theory on hunting by considering the wheel load variation caused by the vehicle motion and (3) to investigate the applicability of this theory to bogie design by comparing the numerically calculated results of hunting with the experimental data which have been obtained from a series of hunting tests using two electric vehicles in service.