This book contains the result of many years of integrated researches of the author concerning the development of scientific basis for the provision of guaranteed railway vehicles motion safety by improving the methods of determination of possible reasons for derailment and destruction of supporting elements of railway vehicles. Impact of various factors on the parameters of dynamics and strength of the rolling stock were studied. Problems of addressing the issues of safe operation of high-speed electric trains were considered. The effectiveness of non-destructive examination of body and bogie frames with the use of a complex of materials science tools and methods of stress-strain analysis of bearing structures was demonstrated. Conditions for safe operation of the rolling stock with Automatic Gauge Changeover Systems were investigated. Based on the result of research, requirements for the admission to the regular operation of the railway rolling stock with variable gauge wheelsets have been determined. Original methods and means of rapid determination of dynamic parameters of railway vehicles motion safety and the impact of the rolling stock on the track were presented.