p. 175-179
According to the decrease of the three-axle bogie for locomotives in Japan, the need for diminution of the gauge widening in curved track has been pointed out by rail maintenance division. Meanwhile, bolsterless bogies which can have more steering ability are employed in many rail vehicles, and wheels with profiled tread have been used widely. For vehicles which have such bogies and wheels, it is expected that the gauge widening still keeps its effect on the curve negotiation even now. In this paper, the curving performance under the presence of gauge widening is investigated in detail considering the recent trend. The wheel lateral forces during curve negotiation obtained by numerical simulation are compared among vehicle types classified with truck mechanisms and wheel tread shapes. As a result, it is shown that the effectiveness of gauge widening exists for bolsterless truck and steering truck, but the availability to the trucks with profiled wheel is little because the change of wheel shape, from conical tread to profiled one, gives much effect on the performance. Then, a modification of shape in profiled tread is examined to get further availability of gauge widening.