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The wheelset and its components (the axle and the wheel) are subject to technical regulation. Therefore, in order to establish the assigned service life in accordance with TRCU 001/2011 (Technical Regulations of the Customs Union) and the examination frequency taking into account the durability parameters of rolling stock components in accordance with VNIIZhT RD 27.05.01-2017, it is necessary to assess the operational loading obtained from the running testing results, with respect to the part strength characteristics which are calculated during the bench tests. At present, to estimate the stress-strain state (SSS) in various machine-building structures, the strain measurement method is widely used, which allows to assess their performance with high accuracy. However, determining the SSS of a wheelset is not only a difficult task due to the constant rotation and movement of the wheelset relative to the bogie, but also expensive due to the employment of special non-contact measuring systems. Development of a dynamic model using modern software systems allows determination the stress-strain state of the wheelset elements by creating dynamic models as a system of perfectly rigid and elastic bodies connected by strength members and hinges. To confirm the adequacy of the parameters obtained in the simulation, verification is carried out according to the results of running dynamic strength tests. Thus, using the obtained model of the rolling stock and the track it is possible to make life and durability assessment as well as optimize the main rolling stock components. On the example of a freight gondola car model, a diagram of the dependence of dynamic stress amplitude distribution on the frequency of the occurrence in the wheel has been obtained, and considering the results of the earlier bench tests of standard specimens and full-scale wheels the period has been determined for durability from the moment of crack initiation in the wheel up to its fracture, as well as the assessment of the safety factor for durability is given.

In article are considered standard technologies of ultrasonic inspection of under-hub parts of press-fitted wheelset axles accordingly to existing regulations: GD (Guidance Document) 07.09-97 and STO (Standard of the Organization) Russian Railways 1.11.002-2008, and proposed improve-ment measures of nondestructive inspection that are confirmed by calculation and experimentally

The article noted the need to improve the technology of repair locomotive wheelsets. We propose a model describing the process of machining tread on milling machines based on thermo-mechanical approach to cutting metal. On the basis of the model is a method for analytical determination of the forces of milling, the temperature front and rear surfaces of the carbides. Presented results of the comparison of experimental data and data obtained analytically.

In article the questions connected with cranking of bandages on the wheel center arising because of weakening of interference fit. Authors suggest to consider the possibility of use of conic interference fit instead of cylindrical. For this purpose considered possible options for manufacturing the proposed connection. Revealed of the optimum angles conjugation aimed at a uniform distribution of metal bandage volume. Designed wheel design can be widely used in traction rolling stock. The result is reduced the duration of the repair of locomotives associated with the replacement and constriction bandages.

The subject of the study is the process of applying optical technologies for non-contact measurements of geometric parameters of a wagon wheelset during operation and repair. The purpose of the study is to study the methods of field testing of technologies for controlling the geometric parameters of car parts using an optical rangefinder, with mutual verification of the results obtained using numerical modeling using three-dimensional digital models of objects and measuring instruments. As a result of the study, experimental and calculated dependences of the optical sensor readings were obtained during the change in the relative position of the measuring object (wheelset) and the rangefinder. Two laser triangulation rangefinders were used for field tests. For numerical simulation, a program was created that allows generating a three-dimensional model of the rolling surface of a wheelset consisting of a set of points belonging to the surface of rotation. The simulation consists in finding the intersection points of a line defined using the coordinates of the point of the radiation source in space and the guiding vector with the model of the skating surface. After the calculations, the result is given in the form of a table with calculated ranges and visualized as projections of a three-dimensional wire model of a wheel and a rangefinder beam. Visualization of the numerical modeling process is important to avoid misinterpretation of the calculation results and to verify compliance with the physical meaning of the numerical data obtained during modeling. Comparison of graphs shows the convergence of the results and sufficient accuracy of numerical models and techniques that can be used in the future to plan full-scale tests of the designed techniques and equipment for dimensional control of railway car parts.

The subject of the study is the theoretical and practical aspects of the application of optical technologies for non-contact measurements of geometric parameters of a wagon wheelset during operation and repair. The purpose of the study is to develop methods and technologies for monitoring geometric parameters of car parts using an optical linear scanner, as well as a method for processing the results of field tests of the results of the application of optical control technologies. The article analyzes the problems of application of standardized methods of technical condition monitoring using manual measuring and control tools in the context of the adopted technology of maintenance and operation of freight cars. As a result of the study, a review of the state of the issue of the use of optical control techniques on the railway was carried out, the strengths and weaknesses of various options for the implementation of measurement techniques were identified and a methodology and a computer program for automating the creation of a digital standard of the object under study (the profile of the longitudinal section of the rolling surface of the wheelset) were developed. Using a digital two-dimensional image of the shadow pattern of the wheel profile, the coordinates of the points of the contour line of the section of the volumetric wheel in the area of the rolling surface are calculated. To determine the coordinates of the envelope of the section, a step function is used, as close as possible to the chiaroscuro image of the wheel contour. After image processing, the result is output by the program in the form of a table with the calculated coordinates of the profile section and visualized using the wheel profile synthesized by coordinates in the program window. The accuracy of the technique used depends on the resolution of the image obtained by the linear scanner. The methodology and program can be used in the future for field tests of the designed equipment for dimensional control of car parts.

The article presents the results of the study of the influence of deviations of certain design parameters of bogie from established normative values on a relative offset from the crests of wheel pair in mezhdurelsovom space of railway transport. Such deviations occur in the process of the gradual wear of moving parts in real-world conditions of rolling stock and lead to a change of kinematic parameters of bogie. An analysis of dependence of lateral displacement relative to the wheelset of railway track from the difference between the diameters of the tapered surfaces of wheelset, skating from lack of alignment of wheelsets and difference coefficients rigidity of springs of bogie. The proposed mathematical model allows to not only diagnose technical condition of wagon bogies during their movements on the straight section of railway track, but also forecast the rolling stock maintenance dates the whole on the basis of position measurements of wheel pairs regarding railway track.

The analysis of the development of the wheels increased hardness on the example of certain manufacturers, and changing regulatory and technical documentation for production (GOST). A mathematical analysis of the comparison operation wheelsets normal hardness of the wheel pairs of high hardness, based on the receipt of freight wagons from production to unscheduled maintenance. For comparison methods were used: Cramer - Welch and Laplace function. The estimation of av-erage mileage of cars on different types of wheel sets of freight cars and production technology. Developed the basic advantages of high hardness wheelsets.

The article discusses the design features of the mechanical and crew parts of the passenger electric locomotive DC EP2K, which directly have or causes an impact on the rail track. The purpose of the work is to consider the features of the interaction of the crew and the track when moving this electric locomotive in small radius curves by evaluating the forces arising in the "wheel-rail" contact of the three-axle bogies of the EP2K electric locomotive under these conditions. The need to solve such a problem is caused by the results of the analysis of statistical data on the wear of the ridges of the wheels of EP2K electric locomotives. These electric locomotives are operated at the united railway landfill, where there are a large number of curved sections, including curves of small radius. To achieve this goal, a design scheme of a three-axle trolley of an EP2K electric locomotive has been compiled, which allows a quantitative assessment of the forces acting in contact with the wheel ridges with the relay heads. According to the calculation scheme, a system of equations has been compiled, the solution of which makes it possible to estimate the forces between the ridge and the inner face of the rail head. Based on the results of the calculation of the guiding forces of the wheel pairs of the three-axle bogie of the EP2K electric locomotive, it is concluded that the values of the guiding force acting on the second wheel pair are comparable to the forces acting on the first and third wheel pairs, and in some variants even exceed the values of these forces. The obtained results can be used for further research on the development of measures aimed at reducing the wear of the ridges of the wheels of electric locomotives of the EP2K series under operating conditions.