The article study conditions for the passage of wheelsets along turnouts from the point of view of ensuring traffic safety. The norms and tolerances for geometric dimensions in the “wheelset - rail gauge” system are interrelated. Proceeding from this interrelation, an analysis is performed on the probability of occurrence of adverse events in the passage through the turnouts of wheelsets having flanges with different wear values. The thickness of the flanges of the car wheels has a great influence on the safe passage by the rolling stock on the allocated switch point. When wheels is running on allocated point, disorders occurred in track gauge, tongue gapping to the stock rail, and in the case of frequent repetition of these phenomena - even bends and breaks in connecting rods directly threaten the safety of driving on turnouts. Within one article, it is impossible to consider all the features of the movement of rolling stock in turnouts. As an example, conditions for the passage of a wheelset through a frog unit are considered. It can be seen from the materials presented in the article that the current normative base of the geometric dimensions of the “wheelset - rail gauge” system is justified by the result of extensive and comprehensive scientific research. The experience of several decades of operation is confirmed by the fact that this regulatory framework provides for the transportation process and the safety of the movement of trains in turnouts. Introduction of changes in the “wheelset - rail gauge” measuring system should be based on analysis of the actual state of wheel sets and the parameters of the track gauge in turnouts. In particular, in order to determine the possibility of changing the rejection size of the minimum thickness, it is necessary:• to conduct mass measurements of wheelsets and turnouts in operation; to perform processing of the obtained data with the identification of dependencies between different combinations of sizes, including relations between the thickness of the flange and the slope of its generatrix; to perform dynamic-strength tests to determine the dependence of stresses and deformations of the elements of the switches during the passage of wheelsets with different thicknesses and angles of inclination of the flanges; to reveal the available opportunities for changes in the “wheelset - rail gauge” measuring system, taking into account the durability and reliability of switch points; to develop a new methodology for calculating the adverse events that occur during wheelsets passage along the turnouts.

Открытое акционерное общество «Всероссийский научно-исследовательский и конструкторско-технологический институт подвижного состава» (ОАО «ВНИКТИ»),

The paper considers methods for analysis of size combinations of wheelsets and elements of switches that are used at determination of dimensions of gutters for check-rail assemblies. The method of limit combinations, from the one side, doesn’t guarantee a reliable train operation on crossing assemblies in real operation, but, from the other side, it makes unreasonably strict demands to the design of the assembly. In order to eliminate the contradictions the paper proposes to use a method of probable compositions that allows not only solving an issue of limited safe dimensions of gauge and gutters, but also determining repeatability of impacts on check-rails in the most loaded cross sections and repeatability of motion paths of wheels on crossing. However, while using this method the authors have revealed a number of contradictions between calculated results and real operation. They show that it is possible to avoid the contradictions by the use of conditional probabilities method that allows calculating probabilities of phenomena for specific size combinations of gauge and gutters. As a result, the authors have concluded that it is the most accurate method of determination of permissible dimensions for gauge and gutters on switches. With the use of the method the authors have determined the maximal values of check-rail wear for straight track made of SP special profiles in conditions of nonexceedance of «impact effect» in bent part of the check-rail for switches with various angles.

The paper is devoted to a problem of passing of rolling stock wheelsets with minimum deterioration of a crossing joint of a switch. The authors have formulated criteria representing necessary and sufficient requirements, on the basis of which it is possible to determine permissible values of check-rails wear and dimensions of their gutters. The paper also presents a method for calculation of rolling stock passage on the crossing joint equipped with check-rails that are not connected to running rails. With the u se of the experimental and calculation method the authors have highlighted stages for determination of stress-strain condition of check-rails. The have analysed the operation of check-rails made of RK special profiles that are mounted to a running rail by inserts. As a result, the authors have assessed the advantages of application of check-rails with mounts that are not connected to running rails. Since the method of check-rails calculation for the operation in other parts of the switch is similar, they have analysed the operation of a protector checkrail for switches and discussed the efficiency and disadvantages of its application.

Load from rolling stock in contrast with weight of a railway track is dynamic and actually is transmitted to the top of subgrade through a ballast bed. That is why it is more complicated to get a value of strain and a form of its diagram on the top of subgrade, which is considered as an external load on the subgrade, than just from the weight of a track. The paper presents a method of calculation of an equivalent train load on a railway track. For the presentation of intension of equivalent loads the authors have considered two typical examples where they have analysed extreme cases with various loads. The paper shows results of calculations by formulas described in the methodology. The equation solutions allow determining a value of the equivalent load of any field of coverage of acting loads including at asymmetric loads regarding to limits of their restrictions. The authors have made a conclusion on expediency of calculation with the use of equivalent loads. As a result, they have formulated a final formula for the calculation of an equivalent train load on a railway track.