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The article presents the results of a study of the effect of the functional relationship between the parameters of the microgeometry of the brake disc surface and the level of the stress-strain state of the contact area on the thermal resistance coefficient. The results of an experimental study of the process of changing the step and altitude parameters of the microgeometry of the surface of the brake disc under the influence of normal and tangential forces realized during friction are obtained. It was found that under the influence of normal and tangential forces, the height parameters of the microgeometry tend to increase, and the step parameters tend to decrease. It is shown that when calculating the contact thermal resistance, it is necessary to take into account the functional relationship between the geometric parameters of the microroughness of the brake disc surface and the level of the stress-strain state of the contact area. The calculations performed without taking into account this connection lead to overestimated values of the contact thermal resistance and, accordingly, to errors in determining the values of heat fluxes passing through the contact area of the mating surfaces. The values of the constants, which depend on the design features of the friction unit of the disc brake and are used to determine the nature of the change in the geometric features of microroughnesses, have been specified. The correction of the input parameters of the microgeometry of the surface of the brake disc is performed, taking into account the dynamics of changes in their geometry under the influence of force loading. It is shown that it is advisable to take into account the dynamics of changes in the surface microgeometry in the analytical determination of the contact thermal resistance of a disc brake. The results obtained are recommended to be used in calculating the friction characteristics and assessing the heat fluxes passing through the area of mutual contact of the brake disc and brake pads of the disc brake.

The contact network is one of the most vulnerable elements of the traction power supply system. The prevailing number of events in the power supply sector is connected with the contact network. The article is devoted to the method of contactless diagnostics of the contact network of electrified Railways. The paper proposes to use a method for diagnostics of the contact network based on optical elements, followed by digital data processing and calculation of geometric parameters. This method is characterized by a low cost of the device in contrast to analogues and high accuracy of calculation. The analysis and selection of optimal installation locations for optical devices is given. The method of contactless diagnostics of wires of the contact network of electrified Railways is presented.

The article discusses the thermal state of the disc brake elements during braking, taking into account the distribution of heat fluxes between the friction elements. The results of the study of the influence of the thermal resistance of the medium filling the microcontact gaps, caused by reversible deformations of the surface microgeometry, on the thermal state of the disc brake elements are presented. Method - the description of the thermal state of the disc brake elements during braking is made on the basis of the Fourier - Kirchhoff differential equation of thermal conductivity, taking into account the influence of the thermal resistance of the medium filling the microgaps between the surfaces of the brake pad and the brake disc. Results of the work: The calculation of the thermal state of a railway disc brake was carried out taking into account the reversible deformations of the microgeometry of the surfaces of the working elements of the disc brake. The exact dimensions and shape of the disc brake elements are specified in the CAD system (SolidWorks). The graphs of changes in the thermal energy generated and dissipated by the disc brake at different initial speed and duration of braking are given. The obtained dependences illustrate the process of heat energy dissipation into the environment. The inertia of the friction system of the disc brake in relation to the dissipation of the generated thermal energy during braking is shown. It has been shown that the distribution of heat fluxes between the working elements of a disc brake depends on the level of reversible deformations of the microgeometry of the brake disc surface, which directly determine the thermal resistance of the medium filling the microcontact gaps. Taking this circumstance into account makes it possible to increase the reliability of calculations of the generated and dissipated energy by the working elements of the disc brake during braking. The results of the study are recommended for use in calculating the thermal state of the working elements of the disc brake during braking.

Purpose. Constructing a model for predicting a quantitative indicator of the pre-discharge state of the upper structure of the track based on a statistical analysis of the seasonal dynamics of this indicator. Forecasting involves identifying bottlenecks for timely corrective action. This approach allows you to refine the construction of algorithms of the functional risk assessment system on the infrastructure of Russian Railways for managing the technical condition of the railway track and safety and is considered as an element of digitalization of the risk assessment of traffic safety in the Railway Infrastructure Directorate. The development is carried out on the basis of accepted existing regulatory documents and classifiers of risk factors operating for the infrastructure management at Russian Railways. Methods. regression analysis, data validation, modeling based on regression analysis. Results. Dependence was identified and a forecast model of the dynamics of the number of deviations of the 2nd degree rail gauge geometry (GRK) was built based on the use of actual data from the automated system Path (APCS P) of Russian Railways. Testing of the approach was carried out on the basis of the Directorate of Infrastructure of the North Caucasus Railway. The identified dependence allows you to give a fairly accurate forecast of the state of traffic safety and the development of GRK deviations on the 2nd degree for use in practice, effective planning of material costs for planned preventive work and overhaul at linear enterprises, on a specific railway adopted for calculation and on the network of Russian Railways. Practical significance. The constructed model allows predicting the intensity of the risk factor on an objective basis of seasonal patterns, as well as the volume of control impacts on the current content of the upper track structure. The presence of such a forecast will make it possible to establish a relationship between the indicator of the dynamics of the number of deviations of the 2nd degree rail gauge geometry, including seasonal dynamics, and the risk factor, that is, the number of GRK deviations of the 3rd degree used in the risk assessment on the infrastructure. The result of this approach is the solution of a system of tasks that affect the values that reflect the level of risks, and as a result, effective management of financial flows for the maintenance of infrastructure, reduction and prevention of traffic safety incidents.