ABSTRACT
This chapter has been designed to provide a hands-on guide to both understanding and analysing longitudinal train dynamics. It improves on previous work in giving a more comprehensive and systematic approach to deterministically modelling draft gears. The approach can be used with both friction and polymer damped draft gears and different draft gear structures. The method incorporates loading and unloading curves, loading rates, hysteresis and structural stiffness and can incorporate either or both friction and viscous damping. The chapter also covers the modelling of the input forces, namely traction, dynamic braking, air braking, grades, rolling resistance and air resistance and curve resistance. Advanced methods of incorporating more accurate traction and dynamic brake performance of the locomotives are also introduced. The relevance of the study of longitudinal train dynamics is given further support by the inclusion of modelling of the interaction of lateral and vertical wagon dynamics with longitudinal train dynamics. Issues surrounding vehicle stability in the presence of large coupler forces on curves and impact forces when coupling heights are mismatched are treated in detail. While the chapter content is, for the most part, specifically focussed on heavy-haul trains, it also includes modelling and analysis relevant to passenger trains and crashworthiness.
