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The problem of the assessment of the continuous welded rail track stability at its thermal elongation is considered in this paper. The method for determining the stress-strain state of various elastic objects developed by the specialists of JSC “VNIKTI” is analyzed on the example of a rail of a continuous-welded track section. The essence of the method is to determine the dependence of the natural frequencies of rail vibrations on the applied longitudinal force. As a means of obtaining such a dependence, a modal analysis of a track section model carried out using the finite element method was chosen. The methodology for calculating the natural frequencies of rail vibrations and the description of the created model of the track section and its properties are presented in the paper, the contact interactions of the model elements and boundary conditions are defined in it. Calculations for determining the natural frequencies and modes of rail vibrations are performed, the first four modes of rail vibrations obtained by calculation and experimental methods are shown. The assessment of the adequacy of the created model of the track section is carried out by comparing the natural frequencies and modes of rail vibrations obtained by calculation, by modal analysis methods and experimentally when measuring vibrations on a full-scale object - assembled rails and sleepers, having a similar design compared with the model. It was decided to use the distance between the vibration nodes as a criterion for comparing the obtained modes of natural rail vibrations. The first mode of vibration is selected for further studies. Calculations were carried out and the dependence of the natural frequency of the first vibration mode of the rail on the longitudinal force applied to it was obtained using the created model of the track section. The obtained dependence can be used in the method proposed by the specialists of JSC “VNIKTI” in order to determine longitudinal force, applied to the rails on the full-scale section of the continuous welded rail track.

The article presents the equivalent circuit of three conductors, taking into account their mutual influence. The equivalent circuit contains the resistance and inductance of each conductor, the conductivity and the capacitance of their insulation relative to the earth, as well as the mutual inductances, conductivities and capacitances of the insulation between the conductors. The mathematical foundations of calculating the distribution of electrical quantities in the system of three conductors are considered, taking into account their mutual influence. An iterative incremental model of the software life cycle was chosen as the basis for automating this calculation, taking into account existing approaches to software development. Specific features of specialized software are specified. A structural scheme of the software complex and a block diagram of the calculation algorithm are proposed. The algorithm is based on the iterative calculation of currents and voltages for three conductors, taking into account their mutual influence. In accordance with the chosen model of the life cycle of the software, three versions of software with different functionality have been developed. This allowed us to effectively organize the processes of testing, debugging and implementation. As a result, the software complex has a window interface containing four tabs and allowing to enter the initial data for the calculation, display the results in the form of graphs and tables. For saving the results of calculations, a connection with the database has been implemented.

Under consideration the method to determine the positive and negative sequences of fundamental voltage and current harmonic in the three-phase power supply systems, based on the Clark transformation and adaptive filtering.

The article covers stability and accuracy for restoration of uneven sampled signals, using basis functions. The accuracy and stability are explored for different transfer system orders, period between basis functions and offset of the basis functions system against restored samples.

In article the issues of electric power imbalance in train traction research are considered, including the method providing an estimation of the contribution of imbalance components to its total value with the possibility of their separation between the participants of the transportation process: the electrification and power supply service, the automatics and telemechanics service, the directorates of locomotive traction and motorized rolling stock. Described method allows in more detail to analyze the factors that affected the change in the components of imbalance and further develop organizational and technical measures to reduce it.

The analysis of wave processes in the system including electric transmission lines, traction substations, AC traction network and electriclocomotives is necessary to accurately assess to energy performance of its work. This system contains concentrated and distributed parameters, consequently the analysis of such a system is difficult and the rolling stock which is also a part of this system represents a dynamic load. The proposed mathematical model of the alternating current traction power supply system allows us to consider electromagnetic processes at its various points taking into account wave processes.

In this article, the problem of assessing the stability of a continuous welded rail track during its thermal elongation is considered. The article considers the method of determining a stress-strain state of continuous welded rails proposed by specialists of JSC “VNIKTI”, which is based on the use of the dependence of natural frequencies of rail vibrations on the applied longitudinal force. Such a dependence can be obtained with the help of the calculation method using a finite element model of a track section. The reliability of such a dependence can be assessed by comparing the results obtained using the calculation method with the actual values of natural frequencies of rail vibrations, depending on the longitudinal tensile and compression force applied to a full-scale facility. The track panel is chosen as such a facility. In order to obtain the actual dependence of natural frequencies of rail vibrations on the applied longitudinal force, a specialized test bench is developed. The development of the test bench included designing the test bench elements and creating finite element models of main load-bearing elements of the test bench - a stop, support and traction, as well as their subsequent strength calculation to confirm the operability of the selected design under necessary loading conditions. The strength is assessed using the safety factor for the yield strength. Calculations using the finite element method have shown that the test bench design has sufficient strength. The developed test bench will allow performing tests for the purpose of the verification obtained using the calculation method of the dependence of rail vibration frequencies on the longitudinal tension and compression force applied to it, as well as for testing the proposed method to assess the rail longitudinal force during its thermal expansion.

Optimization of insulation of walling of building walls is proposed, taking into account the relationship of structural, heat engineering, operating parameters and economic indicators. The purpose of research is to determine the optimal value of the thickness of the insulation with the heat-insulating material of the object, taking into account the thermal energy released to it. The study used methods of mathematical modeling of heat transfer, an optimization problem. The results of the study of the influence of the thickness of the insulating material on the technical and economic efficiency of the building's consumption of energy resources and material costs are presented. The results showed a decrease in heat losses through the building envelope, consumption of heat and electric energy for the heating, ventilation system and reduced costs.

The paper is devoted to the calculation of the electrical quantities distribution in the system of three conductors. The first conductor is located on the surface of a uniform soil and the other two conductors are located at depths of h and h . As result, analytic expressions of current, potential and leakage current density in the first underground construction with considering the influence of the second construction was obtained. The influence of second construction increases the value of electrical quantities in the underground construction. The analytic expressions were obtained using Fourier transform method. The analysis showed the influence of the leakage current and insulation resistance of the second construction on the electric quantities distribution in the first construction

Described the prospects for the use of highly efficient boilers as an autonomous source for generating heat for the priority tasks implementation of the strategy for the development of railway transport in the Russian Federation until 2030 approved by the Government of the Russian Federation. The features of operation and design of a vacuum boiler, advantages and disadvantages are considered. The necessity and method of heat exchange processes intensification in a vacuum boiler to increase its efficiency and reduce fuel consumption are substantiated. The main provisions of the mathematical model for thermal calculation of a vacuum boiler using the k-ε model ANSYS CFX to describe turbulent flows of a reacting gases mixture, taking into account heattransfer by radiation and convection, and the RPI ANSYS CFX model, describing the liquid boiling processes. The results of computational studies using the RPI ANSYS CFX model for boiling on smooth and finned cylindrical surfaces are presented. The computational studies results of the pressure effect in a rarefied volume on thermophysical characteristics and operating parameters of the boiler, such as wall temperature from the water side, heat losses with exhaust gases on a smooth and ribbed surface are shown. The influence of the ribbing coefficient on fuel economy is shown at various pressures. Reasonable recommendations for creating a design of energy-efficient vacuum boilers with improved weight and size characteristics are presented. The application of the design for an energy-efficient of vacuum boiler with transverse ribbing on the outer flame tube surface with rational geometric characteristics is substantiated; a rational coefficient of ribbing Ψ = 1,89 is presented.

The paper considers the influence of the force characteristics of the damping apparatus on the value of the maximal longitudinal forces arising between the cars. Using the computer program MSC.ADAMS, we performed the simulation of shunting collisions of cars and train transient movement modes. The dependences of the maximal forces at cars' collision at various velocities on the shape of the elastic elements' force characteristics are determined. The operation of various shock dampers for the case of the train starting off electric braking and movement through the parts of the longitudinal track profile was estimated. It is shown that shock dampers with a rapidly growing line of load lead to the emergence and propagation of large shock forces along the train, while a slow growth of the force leads to their reduction due to the amplitude increase in elastic vibrations propagated along the train length . We propose to use high-energy-damping devices to reduce the longitudinal forces in the train, which are characterized by the force slew rate substantially depending on the compression velocity of the shock damper.

Shotcrete lining is one of the most common types of temporary supports in tunnel construction. The influence of shotcrete lining on design calculations of permanent lining is difficult, because there is no method of designing at the present time. This leads to increasing in consumption of materials and labour of construction. The information about the influence of the basic mechanical properties of soils, geometrical size of construction per value of temporary shotcrete lining factor was obtained during research. These data formed the basis for futher development method of designing. Empirical correlations of stress distribution between temporary shotcrete lining and permanent monolithic reinforced concrete lining were obtained during theoretical research. Results of experimental research tensity of temporary shotcrete and permanent lining confirmed the possibility of using in the designing this empirical correlations. Using in the designing proposed empirical correlations will leads to reduction in consumption of materials and labour of construction.

The article is devoted to the development of a methodology for monitoring the alignment and radial runout of the inner cylindrical seating surfaces of locomotive motor-axle bearings. The main reasons for the wear of the working surfaces of the bearings and the consequences of the influence of the clearances in the interfaces of the plain bearings and the axles of the wheelsets on the increase in the intensity of wear of the parts and the deterioration of the dynamic characteristics of the running gear of the locomotive are listed. The paper presents a basic diagram of the basing and control of deviations from alignment and radial runout of the inner cylindrical surfaces of bearings, describes the design and principle of operation of a special control device for measuring these deviations. The purpose of the work is to substantiate the feasibility of monitoring deviations from the shape and location of surfaces during the repair of motor-axial bearings. The paper describes the sequence of steps for measuring the alignment and radial runout of bearings and the interpretation of the measurement results. The features of the design of the control device are considered, the advantages of its use are listed in comparison with the existing analogues of the devices used to control the alignment of the holes of the body parts located on the same axis. At the same time, it was found that the control of alignment and radial runout must be carried out in order to assess the possible degree of misalignment of the traction motor frame and the axle of the wheelset of the locomotive after repair. Thus, the conclusions obtained confirm the need to tighten quality control of the restoration of locomotive motor-axle bearings by introducing into the production process the operations to control the alignment and radial runout of motor-axle necks and motor-axle bearing liners made of lead bronze, tin or lead-tin babbits.

This article describes developed «Collector-brush heat» pc-application », which is aimed to automatically process thermal images, received during thermos-vision of DC machine collector-brush unit. This application allows to calculate the thermal rate and to build collector-brush heating curve. The application is developed in order to apply it in the traction drive diagnostics hardware-software complex.

The article describes the current state of railway non-traction electric power supply system in the electric grid complex. The main drawbacks of the existing electricity metering system in 0.4-10 kV distribution networks are shown. The main directions of non-tractive electric grid complex innovative development are considered, including directed to increase the efficiency of electric energy transformation, transmission and consumption processes due to the management of distribution networks operating modes. The basic principles of "Digital district power supply" constructing are given.

Global investment projects of JSC "Russian Railways" to increase turnover suggest an increase in the load on the existing areas of electrified railways, in connection with what is urgent problem of passing the required number of pairs of trains at railway stations. Electricity consumption in railways AC characterized by a rather high consumption of reactive power due to the specifics of electric rolling alternating current, which leads to increased levels of stress and loss of power and, consequently, reduce the energy efficiency and the potential capacity and carrying capacity of the railways. One of the least capital-intensive, and in some cases the only possible rational way to strengthen the system of traction power supply AC is the use of transverse devices for reactive power compensation. The article describes the method of determining the power and choice of accommodations in the area of ​​the railway regulated and unregulated devices transverse reactive power compensation systems, traction power supply 25 kV and 2 × 25 kV. The calculation of the input impedance of the external inductance and traction power supply, the main options for power supply circuits and sectioning traction network devices and placing transverse compensation of reactive power, check to ensure a minimum level of voltage at the pantograph of electric rolling stock. The results can be used as the design of new railway sections, and in dealing with increasing the capacity of sites in operation.

Various converters are operated at electric railways traction substations whose rectifiers design includes plug-in power rectifiers and pill ones. Such a variety of rectifiers design causes the problem of the power supply reliable operation unavailability both of volumes and of quality information concerning the characteristics and diagnostic parameters of power semiconductors rectifiers. For a possible prediction of the diodes and thyristors proper operation, new instruments as well as simple technologies of the preventive diagnostics, correspondent to the state and industry standards and instructions should be developed. One of the most accurate methods to determine not only the serviceability of rectifiers but also to forecast their wear - life, is the diagnostic method of recurrent peak backward current. This method is the basis for the design of a peak backward current meter which is used on the Western-Siberian railway. Using this device the screening of about thirty thousand rectifiers was carried out which resulted in the sorting of out-of-work rectifiers, predicting long term rectifiers conditions. The statistical analysis of the research allowed to determine the number of measures to improve the reliability of traction substations converters.

This paper describes an algorithm evaluating the effectiveness of energy-saving devices and technologies, based on the methods of mathematical statistics. Diagram presented in the article. It can be applied in the traction system and power supply without traction. Approbation of the algorithm is executed in the traction power supply system. The developed algorithm includes five stages: 1. Stage calculate the required number of observations. The basis of this stage is to evaluate the dispersion and calculating on it the desired number of observations. 2. Stage of the collection and processing of data obtained before the implementation of energy-saving devices and technologies. Collection is carried out on of electricity consumption and factors influencing the process of electricity consumption. Processing includes the calculation of the correlation matrix, the coefficients of determination and the parameters of the regression equation. 3. Stage of the collection and processing of data obtained after the implementation of energy-saving devices and technologies. Data collection is carried out according to the parameters selected in step 2 and the processing is done by the calculation of the parameters of the regression equation. 4. Stage of comparing the data before and after the introduction of energy saving devices and technologies. Comparison of the data obtained before and after the introduction of energy saving devices and technologies produced using the Chow test and nonparametric mathematical statistics such as omega-square (Lehmann-Rosenblatt). 5. Stage of calculating electric power saving. The calculation is made on the consumption of electricity obtained by the regression equation before the introduction of energy-saving devices or technology by substituting the values of the factor after implementation and actual consumption of electricity after the introduction of energy-saving devices or technology. Approbation of the algorithm was successful.

The article presents statistical studies of acoustic control signals when diagnosing power transformers of the railway power supply system. Statistical processing of acoustic monitoring data was carried out on the example of transformers with different levels of insulation condition. Comparisons of histograms of the experimental distribution of amplitudes and dominant frequencies of signals with the nearest theoretical distribution laws, performed in the STATISTICA program according to control data obtained from the automated system. The conducted studies have shown a close correlation of defects registered by the acoustic method with the distribution of signals in the form of laws of distribution of random variables. It is shown that for power transformers with mechanical oscillations, both during the passage of the train and at idle, the distribution of amplitudes and dominant frequencies of the recorded signals corresponds to a uniform law. The distribution of amplitudes and dominant frequencies is not centered around a certain average value. For power transformers containing partial discharges, the cause of which is the deterioration of the insulating properties of the windings under the influence of high voltage, the best approximation, both amplitudes and dominant frequencies, showed the Lognormal distribution. The signals are centered around a characteristic mean value. When the train passes, the acoustic system registers both high-frequency signals from the PD and low-frequency signals from body vibrations. There are two components in the distribution law - uniform and lognormal distribution densities. Thus, by the type of distribution of the recorded signals, their amplitude and dominant frequency, it is possible to determine the presence of a defective state of the insulation of power transformers. The study was carried out with the financial support of the Russian Foundation for Basic Research within the framework of the scientific project No. 20-38-90231.

The article is devoted to checking the validity of the hypothesis that the information on a user's computer system, obtained on the basis of covert monitoring of standard peripherals allow timely recognize disloyal behavior and prevent the realization of the internal threats to information security, which is important for the information systems of rail transport.

Single-phase transformer with an additional tap at the middle point of the secondary winding is a very common element in the various electrical circuits, including on-board electric rolling stock. A typical case is powered from the transformer zero full-wave rectification circuit. The aim of the article is to provide a detailed description of the computer model developed by the author of said transformer, built on the basis of a combination of circuit and operational design principles. The proposed model can also be used to describe the process in a single-phase two-winding transformer without additional tap, given the possible connection group I / I-6 or I / I-0. Connection groups can be considered individually for each half of the secondary winding in case of using of additional tap. Shows an example of embedding the transformer model in a more complex computer model of the electric traction DC motors excitation current stabilization system, which includes a computer model of a saturable reactor, thyristor rectifier, system of pulse-phase rectifier control and control loop with a proportional-integral current regulator and boost nonlinearity. Obtained during the simulation graphics excitation current in the field winding of collector traction motor and its reactive component show that the above system of stabilization of the current and its computer model of functional and successfully fulfill their functions: at the downturn of the armature current excitation current is maintained by the growth of the current make-up of excitation control rectifier. The correct operation and ease of use of the developed computer model of a single-phase transformer with an additional tap at the middle point of the secondary winding is stated.

The article deals with the problem of diagnosing the technical condition of the collector-brush unit of DC motors. The topicality of this problem in the engines operating on the railway transport, which are in the most severe operating conditions, is particularly noted. These studies are aimed at improving the reliability of diagnosing the technical condition of the collector-brush unit through the use of a new method of diagnosing the condition of collector DC motors’ commutation. The proposed method of diagnosis is based on a new principle of processing diagnostic information about the spark pulses under the brushes. The article presents the histograms of the distribution of the pulses' intensity of different sections of the armature winding. The research conducted an experiment using a digital control device that allows to identify and digitize a useful diagnostic signal from multipolar brushes with a high sampling rate and transfer it to a computer. Analysis of the experiment’s results showed that the average value of the pulse’s area increases with increasing the spark’s intensity. Nevertheless, severe sparking at the collector leads to the law of distribution becomes double-modal, and as a result, dramatically increases the standard deviation of the values of the pulses’ areas. Described effect makes misinformation in the diagnosis procedure using the parameters of the laws of distribution of the spark’s intensity. The proposed method of diagnosis allows to eliminate this effect. The copyright for a new method of diagnosing is protected by a patent.

The article considers an approach that allows to reduce the asymmetry of consumed currents by traction substations of railways from a three-phase power supply system using a compensating device with an asymmetric structure installed at the substation. Reactive currents of the compensating device allow to redistribute between phases of the traction transformer active and reactive power of asymmetric traction load and to receive symmetric load of three-phase power supply system. The theorem is proposed to determine the conductivities and reactive currents of the branches of a compensating device with an asymmetric structure depending on the traction loads. The article presents the calculated expressions, which can be used to calculate the conductivity and reactive currents of the branches of the compensating device for any traction load of the feeders, in which the equivalent load, including the reactive currents of the branches of the device and the currents of the feeder zones will be symmetrical and active. As an example of the application of the theorem and the proposed expressions, a test problem is presented in which the secondary winding of a traction transformer with asymmetric traction load of feeders is considered, the conductivity of the branches of the device is calculated. With the use of vector diagrams shows the receipt of a symmetrical system of currents of the secondary winding of the traction transformer. Mathematical expressions allowing to realize the necessary law of regulation of reactive currents of the device are given. The necessary ranges control of reactive currents of the compensating device on traction substation on the set probabilistic laws of change of traction loadings are defined. Various options for the practical implementation of a compensating device that will provide the necessary inductive or capacitive current of each branch are considered.

The article describes two methods to estimate the rotor speed of the induction motor using special spectral components generated by the engine design. After you search for these components is possible to estimate the rotor slip. The aim is to compare these methods under different engine loads and to determine the most accurate method. The result is program algorithm for determining the rotational speed of the rotor of an induction motor, which can be used for a variety of practical tasks that require precise definition of speed, but there is no any access to moving parts to install the speed sensor or the use of sensors is undesirable revolutions.

One of the ways to increase the capacity of railways is to use long-distance freight trains with a distributed traction system. In order to reduce the influence of the human factor, it is advisable to use automatic speed control systems on the locomotives of such trains, that take into account the transients occurring in the train. Determination of the longitudinal forces that occur in the train can be carried out by using either a reference mathematical model of the train, or pre-calculated dependencies of these forces on the parameters of the train movement. The second method allows you to simplify the structure and improve the performance of automatic control systems.