Journal of Transsib Railway Studies V.3(63), 2025

The article discusses the causes of freight train breakage, which occur due to a number of reasons, but one of the main ones is a sudden transition from a compressed state to a stretched one. This becomes possible due to a malfunction of the braking system (leaks, blockage of the calibrated air distributor openings) and, of course, the train control technology. Train control technology depends on the characteristics of the traction and braking systems of the rolling stock, as well as on the experience and skill of the driver in difficult track conditions. The dependence of breaks on the season has been established due to the frequent jamming of the wheelset and a decrease in the strength characteristics of the metal of the coupling. In this regard, it is important to solve the problems of train dynamics to determine the rational methods of train driving. The existing methods of model construction are considered. The results of studies of the longitudinal dynamics of a train based on a discrete model are presented. The calculation was performed for two modes: braking and traction, in the time domain, for which the forces acting on wagons and locomotives were determined in advance, depending either on time (traction and braking force) or on the speed of movement (drag force). As a result of mathematical modeling, the values of displacement and speed for each wagon with a multiple of five were obtained. An analysis of the results showed that significant longitudinal forces occur in the middle of the train during braking. The resulting model allows us to study the forces acting on trains with empty wagons, which require relatively minor forces to squeeze out of the train.

The article considers an important scientific and technical problem of determining the transient resistance in the “rail - ground” system, which is of critical importance for ensuring the safety and efficiency of railway transport. The subject of the study is the mechanism of electric current spreading through the ballast layer, taking into account the features of the contact interaction between the rail and the crushed stone. The purpose of the study is to develop a comprehensive methodology for calculating the electrical parameters of a railway track. To achieve this goal, an analytical modeling methodology is applied that takes into account the mechanical characteristics of the system, the resistivity of materials and the influence of the water layer. In the course of the work, a mathematical model was developed that allows taking into account various configurations of crushed stone contact with the rail, including lateral contact and clamping under the rail. Special attention in the study is paid to the analysis of the influence of mechanical stress in the contact zone, surface and volume conductivity, as well as the effects of contamination and moistening of the ballast layer. As a result of the research, methods for calculating transient resistance have been developed, taking into account various factors, and graphs of resistance dependence on key system parameters have been constructed. The practical significance of the work lies in the possibility of applying the results obtained to predict the electrical characteristics of railway tracks, optimize their operation and increase electrical safety. The developed technique makes it possible to take into account the key factors affecting the transient resistance: the condition of the crushed stone surface, volume and surface conductivity, and mechanical stress in the contact zone. This makes it possible to more accurately assess the electrical characteristics of a railway track and make informed decisions on its maintenance and repair. The study showed that surface conductivity (due to contamination and water film) often has a more significant effect on the overall resistance of the system than the bulk conductivity of the material.

The article considers the problem of assessing the impact of charging stations on the load schedules of transformer substations. The solution of the problem is based on the example of facilities undergoing trial operation in the automotive sector of railway transport. The parameters of the electric vehicle charging station and battery are used for a slow charging option based on an AC charging station and a battery with a rated voltage of 346 V and an energy consumption of 48 kWh. To assess the impact of the charging station operation, the results of the trial operation of an electric vehicle are considered. The assessment was performed for a number of load graph indicators. To consider and evaluate the dynamic processes observed during the operation of the charging station, a simulation model has been developed containing a controlled rectifier converter and a charge current limiter implemented using pulse width regulation. The charging station model has voltage and current level control, which are determined based on factory specifications. The results obtained can be used to evaluate the performance of transformer substation schedules when expanding the charging infrastructure, evaluate electricity quality indicators for various circuit solutions used to regulate charge voltage and current, develop demand management measures in electric vehicle charging processes, and develop recommendations for ensuring electricity quality indicators. The results of the work are an assessment of the effect of the charging station operation on the load schedule of the transformer substation, a simulation model of the charging station for testing control algorithms, battery charging protocols and circuit solutions for current rectification and inversion processes.

The article is devoted to the improvement of regression models of the proper resistance of the elements of a grounding device when passing a sinusoidal current through it in order to increase their accuracy. This type of models allows for a fairly high accuracy in assessing changes in physical quantities. The accuracy of the description depends on the number of factors taken into account when constructing the model and the degree of the regression polynomial. The models presented in the article are based on an experiment to measure the proper resistance of the elements of a grounding device, in which a sinusoidal current with the following frequency was passed through cylindrical conductors of four diameters: 10 mm, 16 mm, 22 mm, 28 mm: 25 Hz, 50 Hz, 100 Hz, 200 Hz, 400 Hz, 800 Hz, 1000 Hz. The strength of the passed current varied from 6 to 40 A with a step of 2 A. Due to the large number of factors and the complex nature of the physical processes occurring inside the conductor, a multifactor regression analysis was used. The accuracy of the regression models presented in the article was increased by increasing the degree of the regression polynomial. After constructing the models, their adequacy was assessed and the coefficients of the obtained models were assessed for statistical significance. The adequacy of the models was assessed using the Fisher criterion. As a result of the assessment, it was established that the obtained models are adequate and accurately describe the experimental data. The practical significance of the research is that increasing the accuracy will allow obtaining more reliable information about the value of the intrinsic resistance of the elements of grounding devices, which in turn will simplify further automation of the design and modeling process of grounding devices.

This article examines the problem of reducing the traction properties of freight electric locomotives under the influence of the dynamic component of torque when passing vertical track irregularities, which can reach 20 %. The analysis identified traction drive designs that can eliminate this phenomenon. It was established that traction drives with a frame-mounted traction motor and traction transmission, due to their design features, make sense when using high-torque traction motors with axial magnetic flux, while traction drives with a frame-mounted traction motor and axial gearbox are suitable in cases where modifications to the bogie frame design are permissible. To modernize the existing fleet of freight electric locomotives with asynchronous traction motors, it is proposed to use a frame-mounted drive with an elastic link, which does not require modifications to the bogie frame design. A search for new options for the placement of elastic elements in the frame-mounted drive is conducted. The proposed design includes a modular axle-support traction drive in which the elastic element is a single elastic-compensating coupling. The design also includes variants of an integrated axle-support traction drive using thin-layer rubber-metal components and placing the elastic elements in a hollow anchor or on the wheel centers. A variant of the traction drive design features a frame-mounted traction motor and a double toothed coupling, in which the elastic elements are located in the wheel center disc, and the axle gearbox is supported on the wheel pair via a hollow shaft and thin-layer rubber-metal components. A utility model patent has been received for the proposed designs, and three patent applications have been filed.

A mathematical model has been developed for an adaptive automatic brake control system for a freight train using an Extended Kalman Filter (EKF) to identify the actual parameters of the train and its braking system. To evaluate the performance of the proposed automatic control system, a simulation experiment was carried out using a probabilistic formulation of the research problem and the developed automatic brake control model. The purpose of the experiment is to determine the probabilistic characteristics of the random variable representing the deviation of the train’s stopping coordinate from the specified value. The adequacy of the number of simulation runs for obtaining reliable statistical characteristics in this study was determined using a method for estimating the confidence interval bounds for the sample mean and variance for the given number of trials. Histograms were obtained for the distribution of stopping-point deviation during targeted braking with the EKF algorithm switched off and on. To estimate the probability that the stopping-point deviation exceeds the specified limit, a theoretical distribution law for the random variable was selected and verified using the nw2 goodness-of-fit test. It is shown that without the proposed algorithm for identifying braking system and train parameters (the Extended Kalman Filter, EKF), the deviation from the target stopping point during precision braking can lead to serious violations of train-operation safety. The proposed automatic pneumatic brake control system provides high-quality control, improving the accuracy of targeted stopping of a train at a specified track coordinate. The work was carried out at the expense of budget financing within the framework of the state assignment No. 103-00001-25-02 dated 20.03.2025.

The objective of this work is to evaluate the influence of a series connected spring deflection rate with a hydraulic vibration damper on the dissipative forces of the damper and the dynamics coefficients in the first level of the rail vehicle spring suspension. The object of research is а single-axle three-mass model with two spring suspension levels which corresponds to a four-axle section of an electric freight locomotive. The vertical vibrations of the rolling stock car body, bogies and wheelsets are simulated with a random kinematic disturbance which is the rail irregularities. These simulations perform with two design variants of the spring suspension stage: with a conventional and an elastic-protected hydraulic damper. The simulation also takes into account the elastic and dissipative properties of the track under the wheelset. The perturbation was determined by expressions of the spectral densities of irregularities separately for the low-frequency and high-frequency ranges. The solution of the vibration equations is performed in the frequency domain with the determination of the real, imaginary and amplitude frequency characteristics of the dissipative forces of conventional and elastically protected hydraulic vibration dampers linking the kinematic perturbation with a change in the forces of these dampers. The effectiveness of series connected spring with a hydraulic vibration damper was verified based on a study of the dynamic properties of a simplified three-mass model of a locomotive with a standard and elastically protected vibration dampers. In addition, based on a study of random processes of vertical vibrations of such a model, the values of the dynamic quality parameters were determined, as well as the maximum dynamic forces acting on the dampers. Based on the calculation results, conclusions were made about a significant decrease in the dynamic forces in the elastically protected damper compared to the standard one with an insignificant deterioration in the dynamic quality parameters, which in both calculation options do not exceed their permissible values. It is recommended that the final conclusions be made after solving the problem of optimizing the parameters of the spring suspension on a full-size model of the vehicle.

This paper examines the feasibility of locating rolling stock on a track section based on the track line's input impedance, taking into account the influence of its hardware parameters and external factors. The aim of the paper is to evaluate the feasibility of using the track section's complex input impedance to pinpoint rolling stock locations in conventional track circuits. The article presents the results of modeling changes in the track section's input impedance using a 25 Hz code track circuit, traditionally used on railways in the Russian Federation and the CIS. Three basic track circuit calculation modes were used as input data: normal, shunt, and control. Using the analytical expressions of classical track circuit theory for these modes and the Smath Studio software package, graphs were obtained of the active and reactive components of the complex input impedance versus insulation resistance, the ordinate of the rolling stock's location, and the location of the rail break. The simulation results demonstrated that it is possible to use the complex input impedance of a track section to determine the location of rolling stock with an accuracy of 50 meters and pinpoint the location of a rail break with an accuracy of 100 meters. These results can be used in the development of rolling stock tracking systems, including high-speed vehicles, as well as in diagnostic systems for rail network components, which will ultimately enable the transition to predictive failure detection systems.

Rapid globalization and growing transportation volumes require the implementation of modern technologies and innovative solutions. Therefore, it is essential to effectively plan cargo transportation using various modes of transport. Freight transportation involves moving cargo from the point of production to the point of consumption. Objective: Freight transportation is driven by the need to continue and complete the production of industrial and agricultural products in circulation, after which they become ready for consumption. The proposed methodology for improving cargo delivery will ensure the calculation of all types of shipments, and will also reduce cargo delivery time. Method: The application of this methodology will help define the decision-making process for various plant processes. The proposed model is based on mathematical modeling of process dependencies for effective decision-making. To test the methodology for standardizing transportation times, it is necessary to organize them taking into account the delays of each technological process. The main reason for implementing standards is to expedite cargo delivery and properly distribute penalties between the railway and customers for late delivery. Scope of application of the results: Ultimately, effective freight flow management in rail transport requires a comprehensive approach aimed at improving all aspects of operation, which in turn will contribute to increased freight turnover and the development of the transport system. The effectiveness of this methodology allows for decision planning by studying factors affecting waiting times for ongoing technological processes to improve freight delivery. This model reduces wagon waiting times and allows for monitoring technological processes.

The article examines the problem of fare fragmentation between urban and suburban transportation within the Tashkent agglomeration, which leads to increased passenger expenses and reduced infrastructure efficiency. The subject of the study is the development of a coordinated fare interaction mechanism between different transport modes and the creation of an economically justified model of fare integration. The purpose of the research is to design a unified fare calculation scheme that incorporates a suburban train trip as an integral part of a multimodal journey within the city transport network. The methodological framework includes a comparative analysis of the existing fare systems, assessment of their impact on passenger costs, and the development of a mathematical model for integrated fare formation. A practical approach is proposed in the form of a fixed transfer discount implemented through the ATTO digital platform. The method provides automatic identification of multimodal routes, unification of all trips into a single transaction, and the application of a regulated discount for transfers between suburban rail and urban transit services. The results demonstrate that fare integration significantly reduces total passenger expenses and increases the attractiveness of suburban rail transport. The practical relevance of the findings extends to fare policy development, transport planning, creation of transport hubs, and digital solutions for managing passenger flows. The study concludes that implementing an integrated fare system based on digital technologies will enhance travel accessibility and convenience, improve the efficiency of the agglomeration’s transport system, and contribute to sustainable mobility development.

The article discusses the issue of the fire hazard of the dielectric medium of a transformer (transformer oil), in which, over the period of operation, the characteristics, including fire-hazardous properties, change. The purpose of the work is to study the transformer dielectric medium (transformer oil) for flammability. The article presents the results of laboratory tests of new and used transformer oil to determine the parameters of the ignition temperature and flash point. Statistical data on fires related to electrical equipment are analyzed. It has been established that with prolonged and intensive production, the physico-chemical properties of transformer oil deteriorate. The presented studies confirm that transformer oil can transform from a flammable liquid into a more flammable liquid. Studies to determine the flash point and ignition were carried out using laboratory equipment in accordance with GOST 12.1.044-2018. The reason for this critical transformation is being investigated and a more in-depth analysis of samples of new and used transformer oil is carried out using a Crystallux-4000M chromatograph. It has been established that during the period of operation, transformer oil loses its properties, including an increased fire hazard, namely, the ignition temperature and flash point decrease by 19% and 32.2%, respectively. It has been revealed that due to changes in the chemical structure of the oil, its fire safety index is deteriorating. Attention is focused on the urgency of the problem of timely replacement of transformer oil, as it is one of the main sources of fire danger. Ways to solve it are proposed in the form of: more thorough monitoring of the condition and replacement time of transformer oil.

The issue of designing devices with optimal characteristics of converting an electrical signal and its shape without distortion is relevant when developing a device with small dimensions for electric rolling stock. In this article, the influence of transformer parameters on the form of voltage transmission is considered and recommendations are given on the choice of values of these parameters. This applies to pulse, differential, and low-power transformers. The study of this issue is moving from theory to constructive calculation. In the era of digital twin design, the computational mathematical model of the transformer will allow for a quick decision on compliance with the inherent requirements for the product. Being universal, the proposed model allows performing calculations for any pulse transformer, provided that the appropriate initial data is specified and will allow obtaining an estimated characteristic of the transformer already at the design stage. The study showed the relationship between the transformer design, the materials used for the magnetic circuit and the shape of the output signal. Obviously, the dissipation inductance and the capacitance of the windings are the main parameters that introduce distortion into the signal. Modeling of the winding design and the selection of magnetic alloys or ferrites help to reduce eddy currents in the magnetic circuit, which improves the characteristics of the output signal and reduces the effect of the constant component of the current at the end of the pulse. A transformer model with reduced core dimensions made of steel with a smaller rolled thickness and a homogeneous domain structure, as well as the use of a distributed winding along the core, which has a minimum intrinsic capacitance, had the least effect on the output signal with an acceptable signal distortion of 3 %. The resulting transformer model can be used to create a finished product.

This article discusses a modern method for diagnosing track circuits using broadband signals. The relevance of this research stems from significant shortcomings of traditional track circuits, such as low information content, strong dependence on ballast condition, and high operating costs, which lead to significant economic losses and risks to traffic safety. The proposed approach using broadband signals enables continuous monitoring of track conditions in real time, precisely localizing defects such as breaks, current leaks, insulation deterioration, and microcracks, which is impossible using traditional methods. This not only improves traffic safety but also significantly reduces the number of false alarms. The paper presents a detailed mathematical model of broadband signal propagation, taking into account key attenuation factors: the effect of current leakage through ballast, sleepers, and track connections. A comprehensive analysis of the signal's frequency characteristics was conducted, including a study of the skin effect in rails and the dependence of the complex ballast impedance on external conditions such as humidity and temperature. To minimize signal loss, a comprehensive approach based on adaptive frequency range optimization and data processing algorithms was proposed. The study focuses on the principle of matched filtering, which maximizes the signal-to-noise ratio at the filter output through effective signal compression and intelligent parameter selection. A structural diagram of the diagnostic system with a detailed description of its functional components was developed and presented. The study results demonstrate that the implementation of a monitoring system based on broadband signals enables continuous monitoring of infrastructure conditions without interrupting service, significantly improving the accuracy and speed of defect localization. Practical implementation of the developed method can significantly reduce operating costs and improve the overall reliability, safety, and throughput of rail transport.

Nowadays a frequency-controlled externally excited synchronous motor intensively uses in highly automated high-power electric drives. Earlier there were less reliable and more carefully maintained electromechanical direct current systems in these applications. At the same time, setting up of the closed-loop automatic control systems with subordinate regulation of the synchronous machines is the more difficult task. This is because a synchronous machine is a more complex control object. The purpose of this work is a comparative analysis of transients. In this case, saturation is taken into account according to the magnetic flux in the air gap. The coordinates of the machine are regulated by two different automatic control systems. The first system is typical, which uses field-oriented control of the magnetic field of the stator, the second system is upgraded, it selects the law of control of the magnetic field depending on the static load. Special attention in the current article is paid to the method of accounting for the saturation of the magnetic system of the motor and the construction of a mathematical and simulation model convenient. This article substantiates the feasibility of synthesizing more complex automatic control systems are ones with variable structure. The choice of the magnetic field control law in such systems avoids the negative effect of saturation of the machine's magnetic system on the quality of transients. The models presented in the current work can be used in the design of real controlled synchronous electric drives operating under high loads.