Keywords: vehicle-turnout interaction on tramways, wheel-rail contact, multiple contact, vehicle dynamics, multibody dynamics.

In this paper, a numerical procedure for the analysis of vehicle-turnout interaction for tramways is developed. In tram systems, single-blade turnouts are widely used. In this type of turnout, used only on tramways, a wheelset traveling over the turnout experiences a back-of-flange contact, while the top of flange comes into contact with the groove of the rail in order to achieve a smooth transfer of contact from the stock to lead rails. This is not common in conventional railroad systems since two tongue rails on both sides of the rail are mechanically switched depending on the direction that the vehicle moves. That is, when the wheelset is passing through a branch line in the direction of movement, the back of flange of the inner wheel supports the most lateral contact forces during curving. Also the contact point of the outer wheel on the stock rail is transferred to that on the lead rail through the top-of-flange contact. Such special contact scenarios that include the three-point contact on the tread, back of the flange and top of the flange of the wheel can be encountered and these contact scenarios are not, in general, considered in existing numerical procedures for the analysis of railroad vehicle dynamics [1]. In addition to such complex contact scenarios special for the tram turnout, the radius of the curved track is usually very small, which is, for example, a 30 m curved radius in the case of street crossings. For this reason, the evaluation of flange climb of tram vehicles on turnouts is crucial for safe and reliable operation of tram vehicles. However, as a result of the difficulties associated with the modeling of multiple wheel-rail contacts in the tram turnout, numerical procedures that can be used for predicting vehicle-turnout interaction of tram systems have in the past not been thoroughly discussed. It is, therefore, the objective of this investigation to develop a numerical procedure for the analysis of vehicle-turnout interactions on tramways and discuss the wheel-rail contact dynamics involved in the tram turnout for their safety evaluation. In the numerical procedure developed in this paper, special contact scenarios that include the three-point contact on the tread, back of the flange and top of the flange of the wheel are considered. Furthermore, significant jumps in contact points on the tram turnout can be detected using the combined nodal and non-conformal contact approach [2]. It is demonstrated by several numerical examples that severe wheel-rail contact scenarios encountered in vehicle-turnout interaction on tramways can be predicted using the numerical procedure developed in this paper. Furthermore, numerical results are compared with the on-track test results in order to validate the numerical procedure developed.

1

A.A. Shabana, K.E. Zaazaa, H. Sugiyama, "Railroad Vehicle Dynamics: A Computational Approach", CRC Press, 2008.

2

H. Sugiyama, T. Sekiguchi, R. Matsumura, S. Yamashita, Y. Suda, "Wheel/Rail Contact Dynamics in Turnout Negotiations with Combined Nodal and Non-Conformal Contact Approach", Multibody System Dynamics, 27, 55-74, 2012. doi:10.1007/s11044-011-9252-0

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