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Description
Accurate simulation of noise generation and propagation during train pass-bys remains a persistent challenge in railway acoustics. Most current rolling noise models are forced into a compromise, suffering from either oversimplified assumptions or expensive computational demands. To address this, the present work introduces the fundamental framework for ROLLAND, a novel time-domain model. By applying an explicit finite difference scheme, the approach achieves detailed simulations while maintaining exceptional computational efficiency. The developed time-domain approach allows for the integration of spatially varying track properties and the implementation of multiple, truly moving sound sources. This provides a comprehensive basis for simulating realistic train pass-bys on tracks.At its core, the model utilizes Timoshenko beam theory to characterize bending wave propagation. Moving beyond the limitations of conventional models that often isolate vertical dynamics, ROLLAND also integrates lateral bending, torsional waves, and rail warping, thereby capturing the complex behavior of coupled waves. The framework also accounts for eccentricities in both rail head excitation and rail foot support. In this initial phase, the study focuses on a continuous slab track, modeled as an infinite structure through the application of complex-frequency-shifted perfectly matched layers (CFS-PML). Initial results, focused on the track's impulse response under vertical and lateral loads, demonstrate excellent agreement with an analytical reference model.