Locomotive studies utilizing multibody and train dynamics

Locomotive traction studies have been extensively performed in multi-body software packages. Generally, these research activities have been focused on purely mechanical system design issues and, as a result, there is a limited amount of information available on modeling locomotives under the influence of traction/braking capabilities and train dynamics. Evidence of using results from longitudinal train dynamics simulations as input to locomotive dynamics simulations has also been limited and information on this is rarely presented in the public domain. This means that locomotive traction/braking studies are commonly focused on the dynamics of an individual locomotive and are limited in terms of implementation of intrain forces. Recent progress shows some activities involving the application of approximations of lateral coupler forces to replicate a locomotive's dynamics on the track. However, such an approach has its own limitations and does not fully depict the real behavior of locomotives. At this stage, the optimal technique capable of covering all locomotive behavior issues when traveling in a train configuration is to use a co-simulation approach between a multibody software package and a train dynamics code. This paper describes a methodology for the development of such a technique and presents numerical experiments for locomotive dynamics studies. The results obtained from co-simulation runs for three heavy haul locomotives in a head-end consist, taking into account in-train forces and speeds, are discussed along with limitations found during the development process. © Copyright 2017 ASME.