Contact Geometry Between a Wheelset and Track. Calculation Algorithms and Contact Geometry on Switch Track.

Contact geometry between a wheelset and track is a fundamental problem of railway vehicle dynamics. This paper scrutinizes two dimensional contact geometry. Firstly, the independent variable of the contact geometry is investigated. It is shown that the roll displacement of a wheelset is superior to the lateral displacement as an independent variable especially in flange-contact area. Secondly, minimum-value search for the contact problem is investigated. It is shown that the gradient method is superior to the displacement method from the view point of calculation time. As an application of the algorithms, contact geometry on switch track, which is important in view of safety, is calculated for worn profiles as well as designed profiles.