Forced-steering designs have been proposed to improve significantly the curving performance of rail vehicles without sacrificing stability. To predict the curving behaviour of these vehicles, dynamic curving model has been developed. This computer model, called DYNCURV, simulates a rail vehicle traversing a spiral transition followed by a circular curve, and features automatic generation of the equations of of motion with significant non-linearities included. Validation of the model is accomplished by comparing its results to experimental data obtained for a prototype forced-steering vehicle.
The main conclusions are that:
- The model DYNCURV is capable of providing reliable predictions of dynamic curving for forced-steering rail vehicles.
- Considering that a significant portion of curved track is made of transitions and also, that large fluctuations in dynamic response can occur in the transition due to non-linear suspension forces, dynamic curving simulations represent the most reliable method of obtaining valid curving performance predictions. Although expensive, full scale experiments can also be used to obtain curving performance information.
- The small wheel-all angles of attack maintained by forced-steering vehicles represent their major advantage over conventional vehicles
- The curving performance of forced-steering. vehicles is not influenced significantly by differences in creep force predictions, including half-creep coefficients, and
- When two-point contact exists, the frictional work done by flange forces is generally much greater than that of tread forces.