Automated Generation of US Class 6 Track Irregularity Spectrum Files for Railway Dynamics Simulation

The automated generation of US Class 6 track irregularity spectrum files constitutes a critical component for railway vehicle dynamics simulation excitations. Developed under the standards of the Federal Railroad Administration (FRA), these files simulate vehicle movements—including vertical, lateral, and alignment motions—by modeling track irregularities through spectral density functions. The generation algorithm typically incorporates key parameters such as track curvature, gradient, and elevation variations, combined with vehicle properties like mass, velocity, and suspension characteristics. Implementation often involves Fourier synthesis or inverse transformation techniques to convert power spectral density (PSD) data into spatial-domain irregularity profiles. These computationally generated files enable accurate prediction of vehicle dynamics under diverse track conditions, providing foundational data essential for enhancing railway vehicle safety, ride comfort, and operational performance through high-fidelity simulations.