A Nonlinear Rail Vehicle Dynamics Computer Program SAMS/Rail: Part 3—Applications to Predict Railroad Vehicle-Track Interaction Performance

The dynamic response of a railroad vehicle traveling at speed over track deviations can be predicted by using multibody simulation codes. In this case, the solution of nonlinear equations of motion and extensive calculations based on the suspension characteristics of the vehicle are required. Recently, the Federal Railroad Administration, Office of Research and Development has sponsored a project to develop a general multibody simulation code that uses an online nonlinear three-dimensional wheel-rail contact element to simulate contact forces between wheel and rail. In this paper, several applications to examine such issues as critical speed, curving performance at varying cant deficiencies, and wheel load equalization are presented to demonstrate the use of the multibody code. In addition, the application of the multibody code can be extended to train a neural network system. Neural network technology has the ability to learn relationships between a mechanical system input and output, and, once learned, give quick outputs for given input. The neural network can be combined with the use of a nonlinear multibody code to predict the performance of multiple railroad vehicle types in real time. In this paper, this system is briefly presented to shed light on the optimum use of the multibody code to prevent derailment.