Analýza vad a lomů kolejnic

Abstract

This thesis is dealing with the causes of defects in rails. It is an extensive topic to which has continually been devoted a pertinent attention. In this thesis it was not possible to describe in detail all the aspects of the subject, therefore an attention was paid to the most important and the most common causes of rail defects, many of which could lead to the final failure. This thesis describes the most common and the most serious factors that affect the formation of defects or subsequent failure. These factors may be affected by ongoing and regular inspections of rails by a number of methods. In this work factors exhibiting the strong effect on the development of degradation processes are discussed. Among the most crucial factors definitely belong the axle load, frequency of traffic, slope of the track, climate conditions, the wheel flange wear rate and the wheel profile, permitted speed in a given track segment frequency of stops (braking and start-up power) and the age of rails. In the thesis the most common types of rail defects and their causes are discussed. Described rail defects are classified according to the applicable standards. In a limited extent requirements on the rails microstructure are listed, which are reflected in mechanical properties specified in the current European standards. The experimental part of the thesis focuses on investigations on rail failures originating from two inspected track segments.