Advanced co-simulation technique for the study of heavy haul train and locomotive dynamics behaviour

Heavy haul train studies are generally focused on the calculation of in-train forces, train speed and driving strategies. Longitudinal train dynamics simulations generally include consideration of traction effort and dynamic braking characteristics in their analyses, but do not consider wheel-rail contact and traction control behaviours of locomotives. On the other hand, locomotive dynamics studies are primarily focused on the dynamics of individual locomotives and do not consider in-train forces other than the tractive efforts able to be realised. It has recently become common to use an approximation or in-time series of lateral coupler forces to replicate a locomotive’s dynamics in curves. While this is very important for the analysis of locomotive dynamics, it does not provide any benefits for train dynamics studies that require more accurate results and progressive adjustments in locomotive tractive efforts to be used during simulations. This means that this approach should provide benefits in both respects, and more development should be done in this area. One of the techniques that allow achieving this is the application of a co-simulation approach between a longitudinal train dynamics simulator and a multibody software package. This paper describes a methodology for the development of a bi-directional co-simulation interface between an in-house train dynamics code and Gensys multibody software. This can be used for detailed modelling of locomotives and their traction control systems. The validation of the proposed technique is performed by means of numerical experiments for train and locomotive dynamics studies with their operation over a hypothetical heavy haul route. The proposed technique allows taking into account the effects of lateral coupler forces, speed and traction characteristics and understanding their influence on the results in both software packages.