In the initial part of the thesis we acquaint with rails, which are specially design steel beams - parts of the substructure of the railway line and the most important elements of the railway tracks. The beams perform the function of managing the acquisition of vehicles and direct traffic loads of transport assets. We presented the iron alloy – steel, which is the basic material for the production of rails. We describe in detail the development of the rail and the process of making rails through history. We presente constituent elements and characteristics of rails and describe the most typical types of rail defects and their properties.
In the second part of the thesis we review existing data on the recorded rail defects on the whole railway network of the Republic of Slovenia and analyze defects in rails for each of the main routes. We compare the main routes according to the number of defects on the rails. Upon analysis and comparision, we conclude that the single-track lines stand out by the number of defects per track kilometer. We also observe that one double track lines stands out by the number of defects on rails considering the utilization of the line. The analysis of the Pearson correlation coefficient shows that the number of defects on rails linearly increases with decreasement of the temperatures. For other observed parameters (rail wear, rail age, speed on the track, axle load, the volume of traffic expressed in gross tonnage and gradient), the correlation analysis does not show any particular linear dependence.