Dynamics of railway vehicles are strongly influenced by the wheel/rail contact forces. Wheel/rail contact geometric characteristics are important parameters to determining wheel/rail contact forces. In general, geometric relations between wheel and rail are represented by nonlinear functions of the wheelset lateral excursion and the relative yaw angle. There are some analytical and experimental studies to show the influences of the wheelset lateral displacement on wheel/rail geometric relations. Recently radial steering bogie which is designed to have flexible yaw motions of wheelsets was developed to improve curve negotiation performance. The radial steering bogie makes it important problem to study the effects of wheelset yaw motion on wheel/rail geometric relations. This paper describes the method to analyze 3-dimensional wheel/rail contact geometry considering wheelset yaw motion and describes also some computer simulation results.