Tokariev S. Improvement of the maintenance standard and design of railway crossovers

The thesis is dedicated to solving a scientific task of improvement of the maintenance standards and design of railway crossovers. In present work the modern designs of crossovers were analyzed and new development trends of an under-rail base within turnouts and crossovers on domestic and foreign railways were established. A progress analysis of the theoretical and experimental researches of the rolling stock-track interaction within straight and curved track, as well as turnouts, which together form any layout scheme of crossovers, has been carried out. A method for estimating the crossover position in plan has been developed, which allowed to establish the relationship between the permissible train speed and irregularity size. The mathematical model of the rolling stock-track interaction has been improved, which allowed determining features of the force action of the rolling stock on track within the crossovers more accurately. According to the experimental results the influence features of the freight wagons on the railway track stress-strain state within the connecting part of crossovers were analyzed. Based on the results of theoretical calculations via the verified mathematical model, the most unfavorable layout scheme of single crossovers by the criterion of impact on railway track and traffic safety was determined. For obtained scheme, the ratio of the norm requirements for a simple track and those obtained by modeling was established, which allowed improving the maintenance standards for crossovers both in horizontal and longitudinal direction. In this work has further developed the calculating method of crossovers which supplemented by checking the intersection of the beam ends of the lateral and straight directions. The proposed additions allow at the design stage to determine the maximum length of beams placed without violating the layout scheme, and allows to reduce the costs associated with transportation and laying. For solving the problem of the beam edge intersection, the design of crossovers has been improved due to the using of a prefabricated under-rail base allowing to be placed them at the inter-track distances less than 5.0 m.