Noise is a serious environmental side effect of rail transport, freight transport in particular. Significant contributors to railway noise are the mechanical vibrations produced by vehicles due to rail roughness. Our paper presents an application of the loading force identification method, based on the inversion of regressive parametric models, in the reconstruction of rail roughness. Rail roughness is identified from the accelerations of vibration signals measured on the axle boxes of rail vehicles in motion. Our article shows an experimental verification of the proposed method.