This promotion thesis is devoted to modeling and experimental investigations of railway transport noise spectra. The spectral features of railway transport noise on Latvian railway are investigated and the character of change of spectra depending on traffic speed, rolling stock type and track conditions is evaluated. The analysis of deterministic, statistical, semiempirical and empirical models is performed and the EU standardized RMR (Reken - en Meetvoorschrift Railverkeerslawaai) model is improved for application in Latvian railway conditions. The improved modeling method based on experimental investigation results is an important contribution to the development of railway transport technologies on Latvian railway. Work results have been implemented within the framework of joint projects of Riga Technical University (Institute of railway transport), Latvian railway and Ministry of education and science of Republic of Latvia.