In this Doctoral Thesis rail steels are considered according to standards EN 13674-1:2011 and GOST R 51685-2013. Rail steel defects and reasons for their causes are reviewed. The statistics of damaged and heavily damaged rails in the network “Latvijas dzelzceļš” in the period 2011–2019 is studied and analysed in detail. The statistics of rail grinding train operation in “Latvijas dzelzceļš” within the year period 2011–2019 is gathered and analysed. A research of hardness of 60 E1 type rail running surface, of metal chemical composition of the damaged rail with code X 10.1., and structure analysis was performed. Likewise, statistics of wheelset rejection in the network “Latvijas dzelzceļš” in the period 2016–2019 are gathered and analysed, as well as the number of wheel rim defects in the railway of Russian Federation. The main defects of wheelsets are reviewed. The actual wear of wheels and rails in Latvia and the stated wear in the railway of Russia are modelled. Repair profiles of rail head grinding for Latvian rail ways are modelled and their influence on side wear determined due to the rail and wheel surface interaction. Calculations regarding the wheels with flange angle of 66.8° from worn out profile durability coefficient were performed for Latvian railway according to the entry conditions on rail profiles, developed in this dissertation. A rail grinding method was developed. The wheelset repair and wheel grinding economic expenses were calculated. Recommendations for wheel and rail side wear reduction are presented. The Doctoral Thesis has been written in Latvian. The thesis contains 5 chapters, conclusions and recommendations. The reference list includes 65 titles.