Each of four wheel in one bogie has a different wheel/rail contact point because of understeering in a sharp curve negotiation. In general, the gauge corner of outside rails and the top of inside rail are lubricated in a shape curve. Each of wheel/rail contact points makes different friction coefficients. Therefore, a bogie has several curving performances according to the each of wheels friction conditions. In this study, an ideal condition in a sharp curve negotiation is proposed by selecting a lubrication combination for each of wheel/rail contact points. The result of stand tests about the influence on curving performance of conditions of wheels lubrication and the evaluation of wheel/rail contact force above are also reported.
