Table of contents

The materials of the conference present the results of theoretical and experimental studies of the dynamics and strength of rail transport, wear of wheels and rails, traffic safety and materials science.

List of Editors are available in this pdf.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

● Type of peer review: Double-blind

● Conference submission management system: the conference is being held of-line, but some participants, in connection with the COVID-19 pandemic, will take part on-line using scientific conference organization and administration software ZOOM platform

● Number of submissions received: 46

● Number of submissions sent for review: 46

● Number of submissions accepted: 41

● Acceptance Rate (Number of Submissions Accepted / Number of Submissions Received X 100): 89.1%

● Average number of reviews per paper: 4

● Total number of reviewers involved: 10

● Any additional info on review process: all articles have been tested for plagiarism

● Contact person for queries: Ursulyak Ljudmyla Viktorovna

● lydm.urs@gmail.com

The article presents the analysis results for the parameters measurements of the rail track and the ratio between values of the vertical and side wears of rails in curves of different radii under different operating conditions. It is shown that the installed elevations of the outer rail do not meet the contemporary requirements in increasing the efficiency of the track while minimizing the rail wear. At the second stage of the research, various sections were examined by type of traction, technical equipment, plan parameters and the longitudinal profile. As an example, the results of calculations are presented in Lviv-Rava-Ruska section as a promising project that can ensure the integration of railway transport in Lviv-Warsaw direction. Analysis of the results obtained with the help of the software package – MoveRW and RWPlan programmes, allowed to determine such a combination of elevations of the outer rail in curves, so that trains of different categories realize the lowest values of cross unbalanced accelerations, which provide the minimum wear of rails in compliance with regulatory requirements for unbalanced acceleration, changing this acceleration in time, elevating speed of a wheel on the removal of the outer rail.

The authors of the article analyzed existing software systems that are used to study the dynamic behavior of rolling stock, and also emphasized the importance of using a computer experiment to implement this task. An improved spatial mathematical model of the dynamic behavior of a freight wagon when it interacts with a rail track is considered, and it is proposed to study it using an object-oriented approach using the Maple software package. To accomplish this task by writing procedures, separate modules (subprograms) were created that included differential equations of motion for the individual components of the object under study. Based on existing procedures, the main module was created, which reflected the sequence of performing certain functions (calling up the necessary information, especially the use of logic, methods for solving the problem, as well as visualizing the results). Using the created modules in the Maple software package, a computer experiment was used to study the dynamic behavior of a freight car when it interacted with a rail, and also showed the possibility of taking into account the influence of individual parameters of its technical condition on its dynamic behavior.

When considering issues of increasing train speeds, it is necessary to conduct a preliminary assessment of the entire train dynamic characteristics and forces acting in the elements of cars and a locomotive, as well as in inter-car connections when driving at high speeds along a path of arbitrary shape in plan and profile, and also to consider emergency situations, which may take place during the motion. This in turn requires the development of reliable mathematical models simulating the train motion. The study of dynamic characteristics of railway rolling stock is associated with the consideration of vibrations of complex mechanical systems with a large number of degrees of freedom. The vibrations of cars in the train can be described either by one-dimensional or spatial model. The aim of this work is to show that for some studied cases the modelling of train motion by 3D models more accurately reflects the processes occurring in a moving train. Some results are discussed in the paper.

A brief description is given of the comprehensive modernization of standard freight car trucks through the use of devices of American companies adapted for railways with a 1520 mm gauge and wheels with ITM-73 specially developed wear-resistant profile, which allows several times to increase the resource of problematic running gears. An approximate method is proposed for solving the wheel–rail interaction problem with determining the position and size of non-elliptic contact patches, including with conformal contact. Using this method, new profiles have been developed for turning worn wheels (ITM-73-01), as well as new wheels for cars with an axial load on rails of 23.5 tf (ITM-73-02) and 25 tf (ITM-73-03). The data of experimental studies showed that the average wear rate of the wheel flanges of freight cars with complex modernized trucks equipped with wheels with ITM-73-01 profile is 3.5-5 times lower than that of a standard car with a standard wheel profile. According to forecast estimates, the use of wheels with profiles ITM-73-02, ITM-73-03 will allow to achieve even greater increase in the resource indicators of wheelsets for wear of the flanges.

Railway track stiffness is one of the main parameters that determine the track and rolling stock interaction. The inelasticity of the rail base may occur for two reasons: either as a consequence of the deteriorated condition of a track or due to the structural features of a section. As a rule, areas before bridges or tunnels are treated. Today, there are several options for relevant design solutions. The main purpose of this work is to determine the characteristics of a "railway track" object with which it can be represented in the rolling stock models in the simplest way possible but adequate for sections of transient stiffness. The railway track is introduced into the rolling stock model as a sequence of elements with which the wheels of the rolling stock interact. It is assumed that a single element in its characteristics must be equivalent to the track response when passing the wheel from one inter-sleeper section to the next one, that is, to reproduce a sequence that is cyclically repeated. Such a track element will be characterized by reduced mass, stiffness and dissipation factor.

The dynamic loading of the flat wagon supporting structure during the military equipment transportation and conducting fire from it is investigated. A flat wagon model 13-401 by the construction of Dniprodzerzhirsk Car Building Plant (Ukraine) was chosen as a prototype. It was taken into account that the flat wagon was loaded with two anti-aircraft systems of muzzle energy of 89 kJ. The accelerations acting on the supporting structure of the flat wagon are determined using mathematical simulation. At the same time, it was taken into account that a simultaneous shot from two anti-aircraft systems is carried out. The solution of the mathematical model was carried out in the MathCad software. It has been found that the longitudinal accelerations of the flat wagon supporting structure were about 36 m/s², and the vertical ones were about 5 m/s². The obtained accelerations were taken into account when determining the equilibrium stability of the flat wagon, considering the conducting fire. The stability factor in this case was about 9. The calculation results of the strength of the flat wagon supporting structure are presented. The calculation was carried out in a quasi-static state. It has been established that the maximum equivalent stresses occur in the areas of frontal stops of the automatic coupling and amount to about 300 MPa. The results of the research will contribute to the creation of innovative flat wagon load-bearing structures for the military equipment transportation with the possibility of firing while moving.

Comprehensive studies of the interaction of the railway track and the investigated rolling stock under accelerated conditions have been carried out. The basis of the research was to obtain and substantiate the process of stress state, force interaction of the railway track and the rolling stock under conditions of accelerated movement. Introduction of the new rolling stock into continuous operation is a serious task that must be solved comprehensively. The implementation of this direction significantly affects the reliability of the elements of the railway track. Within the framework of the research, the approach was used that takes into account theoretical and experimental parts of the research using the methodology of prof. O. P. Yershkov. As a result of the studies, average stress values were established: in rails, they variate within the range 44.37...70.99 MPa; in the sleeper, they reach 0.78 MPa; in the ballast layer, they have 0.13 MPa; in the body of the subgrade, they reach 0.04 MPa, which is significantly less than the maxima allowable values. While speed change from 140 to 160 km/h, the values of the studied parameters decrease: vertical force (9.39 %), lateral forces (19.79 %); stresses in the edge of the rail flange (15.86 %); stresses in the edge of the rail head (16.67 %); stresses in the neck of the rail (8.74 %). The obtained results made it possible to form trends and recommendations on the feasibility of further increasing speeds development. At the same time, this made it possible to substantiate in more detail the operation of the railway track in the case of accelerated movement.

According to statistics, receipts of forensic railway-transport expertises related to the derailment of freight wagons annually grows. At the same time, an analysis of the available mathematical models of freight wagons for the study of such cases showed that at present they are not sufficiently detailed to the extent that it is necessary to analyze the causes of rolling stock derailment. Therefore, taking into account the main reasons that occurrence of such railway accidents over the last five years on the railways of Ukraine, the article selects the main directions for improving the mathematical model of a freight wagon. These directions, in turn, should cover the whole plural of factors (explicit and hidden) and identify the most significant ones regarding the circumstances of the derailment rolling stock off the track, established on the basis of a computer experiment. An algorithm and a mathematical model are proposed taken into account the influence on the dynamics of the wagon of process of closing gaps in the axle-boxes and slides, and the equations of motion of the wheelset are supplemented by a guiding force, whose value is one of the main indicators of the stability of the rolling stock.

The design features of a motor-grader help it perform a wide range of working operations, which puts it on a par with the main machines in the construction industry. Unlike other earth-moving machines, the motor-grader can perform work operations not only in a cyclic mode, but also in a continuous action mode. Considering these features, not only productivity should be addressed as the main indicator of the efficiency of this machine, but also the indicators of the quality of the working operations performed, in particular, the indicators of road-holding ability in the process of performing continuous working operations. The work has substantiated and developed a mathematical model of the motor-grader movement during working operations. This model makes it possible to predict the expected trajectory of the motor-grader on the basis of deterministic dependencies, which enables to assess the indicators of road-holding ability. The difference between the proposed model and the existing ones is the consideration of a two-stage mode of machine movement: plane motion at the first stage and rotational around the stop point at the second. When describing the external forces acting on the motor-grader, the differences in the formation of resistance forces on the blade during various working operations are taken into account.

The technical level of rolling stock of railway transport directly affects the economic indicators of the transport industry and the economy of the country as a whole, which leads to the need for improvement of the control, quantitative assessment of the dynamic loading o f rolling stock to ensure safe and reliable communication at the railways. Therefore, in the process of designing and operating the rolling stock the quantitative assessment of dynamic loadings is a relevant scientific and technical problem. The purpose of this work is to study the influence of different types of rolling stock, taking into account the speed of movement on their main dynamic indicators and indicators of interaction of track and rolling stock. The basis of the research is the method of mathematical and computer simulation of the dynamic loading of a freight car using the model of spatial variations of the coupling of five cars and a software complex developed in the branch research laboratory of dynamics and strength of rolling stock (BRL DSRS). Theoretical studies have been carried out under condition of movement of several types of freight cars: a gondola car of the model 12-532, a hopper car for coal transportation of the model 12-4034 and a flat car with a long cargo of the model 13-401 and typical bogies 18-100 with the speeds from 50 to 90 km/h in the curves with radii 350 and 600 m, with superelevation 130 and 120 mm, correspondingly.

The paper presents the main indicators of the renewable energy sources in the railway transport structure of European countries. A new structure of railway power supply systems, energy storage systems and control algorithms under the conditions of stochastic mode of renewable energy sources operation are defined as the main problematic issues. Further directions for sustainable development of such systems and factors that influence the modes of operation of traction substations and electric networks were identified. Average power and a random component are two criteria that were used to build local systems. The paper presents the real schedules of daily load on the traction substation terminals and solar insolation with determined power distribution changes. The power deviations indicators depending on the time interval and the type of generation were determined. A normal law of distribution of a random component was determined as a result of all calculations. It is possible to determine the shortage or excess of electric power in the local system in a certain area and to plan the direction of its development in the near future by analyzing the nature of the determined average power change.

The solution to the problem of monitoring the railway track, as well as potentially dangerous objects and phenomena in the adjacent territories, is determined by the need to implement increased requirements for traffic safety (primarily to the geometric parameters of the devices of a long railway track under construction and functioning load-bearing highways), prevention of technological disasters and large-scale negative effects of natural phenomena on the railways. The continuous process of integrating methods and means of monitoring and preventing emergencies into a single information management system is shown. The possibility of determining a dynamic model of the adverse effect of the train on the track and the most unfavorable for the track train and traction parameters, which must be avoided when forming trains in this section, is established. Three key factors are formulated, the use of which will reduce the negative impact on the track from trains. The concept of information technology improvement of the monitoring system for potentially dangerous sections of the railway on the basis of new innovative technologies has been developed.

The primary task of a greenhouse is to create optimal microclimate, which doesn't depend on external climatic conditions, to grow plants. We can observe significant air temperature and humidity difference in a traditional greenhouse during 24 hours. The stable microclimate in greenhouses is provided by different engineering systems such as heating, ventilation, lighting, etc. These systems require a lot of energy. Saving energy and reducing the mode of temperature amplitude inside the operating greenhouse during exploitation period can be achieved by using solar energy in the greenhouse heating system, namely, by using heat accumulators. However, the test method of optimal heat accumulator to equalize the temperature amplitude inside the greenhouse wasn't described in any research. The purpose of this research is to determine the optimal heat accumulator for equalizing temperature amplitude inside the greenhouse under atmospheric effects in spring. The experimental research of the heat-humid regime was carried out for the greenhouse without any heat accumulation. Relationship between the volume and the surface area of the accumulator and its efficiency was identified.

The paper is presenting the procedure used for establishing the cause of the wagon derailment. To do this, the computer simulations and the computational software, developed in the Dnipro National University of Railway Transport (DIIT) were used. The level of longitudinal forces and the wagons dynamic performance have been evaluated using the mathematical models of longitudinal oscillations of a train and the spatial vibrations of wagons, in particular of tank wagons. As a result of modeling we obtained oscillograms of longitudinal forces in each inter-wagon connection, the dependence of the largest longitudinal forces on travel time and distance traveled, the distribution of the maximum longitudinal forces along the train length, the speed dependence on travel time and track coordinates. We also obtained the dynamic performance of wagons: the vertical dynamics coefficients of the axle-box and central suspension, the horizontal dynamics coefficients and the derailment stability coefficient. The influence of the movable load in the tank wagons and the characteristics of rail irregularities on the stability coefficient against wheel climbing onto the rail is also considered. The presented methodology was used to determine the cause of the tank wagon derailment in a non-homogenous freight train consisting of 50 wagon tanks on an existing track section of the Lithuanian railways. When simulating the train movement, it was assumed that the train was equipped with elastic-friction absorbing devices and air distributors, turned on to the average operation mode. As a result of numerical experiments, an assumption was made about the cause of the train derailment.

The statistical and monitoring data confirm the significant impact of the operational mode on the most important noise and vibration parameters, which is relevant for ensuring the efficiency and quality of the operational process with regard to ergonomic and environmental requirements. The article analyzes the acoustic parameters of rolling stock of the railway, emphasizes the peculiarities of noise emission from various elements of rolling stock and a track. Existing approaches towards solving the problem in the organization of railway noise control are outlined. On the basis of existing modern methods for measurement and analysis of acoustic parameters, the authors propose conceptual approaches toward monitoring the acoustic parameters, predicting noise characteristics and constructing the noise maps of railways. The algorithm of the developed acoustic model for the operational monitoring of noise load and the possibility to compile a case of noise maps for Ukrzaliznytsia is presented. The proposed algorithm allows at given basic design parameters and speed of rolling stock, known sound-absorbing and dissipative characteristics of all elements to carry out a rational selection of noise-protective measures in accordance with the sanitary noise regulations for a specific receptive facility.

Ukrainian passenger multiple-unit train upgrading supposes on creation of new power heads with passive safety systems (PSS) to save passengers lives, to reduce rolling stock damage and to minimize consequences at collisions. The purpose of this research is to develop energy absorption devices (EADs) for power head PSS according to DSTU EN 15227. EAD 1, EAD 2, EAD 3 designs have been developed with using successful experience of EP20 locomotive EADs creation and EAD prototype crash test results. EAD 1 design includes two elements which are located sequentially. Element 1 is a box with a single-layer package of hexagonal honeycombs inside. Element 2 is a truncated pyramid of honeycombs with triangular cells. EAD 2 design has three steps in element 2 form. EAD 3 design has been developed on the basis of element 1. It has been recommended to install two EAD 1 in a power head frontal part at the coupling level, two EAD 2 in power head window-sill part and two EAD 3 in the inter-car connection at the coupling level. Finite element simulation of EAD plastic deformation at an impact has been carried out for determination of design parameters.

The problem of railway transport electromagnetic compatibility automation systems in recent years has been aggravated by the use of power frequency converters in electric transport drives, which significantly increase the efficiency of traction characteristics of 3-phase electric engine. However, estimate relevant harmonic levels in the frequency range used in track circuits of railway automation and telemechanic systems. The paper provides theoretical justification for practical measurements of interference. It is shown, that the interference coefficients monotonically increase in the following cases: 1) increase in the value of the harmonic frequency; 2) increase in the propagation constant, taking into account the supports resistance of the contact network; 3) increase in the circuits track length. Operating frequencies of tonal track circuits up to 800 Hz, the interference increase rate in given length of the rail circuit slows down. The increase in interference coefficients depending on the mentioned factors is explained by the fact that with current part growth of the harmonic flows from the traction substation through the earth increases and thereby creates currents asymmetry of the track circuits.

Intensive environment pollution takes place during coal transportation in open wagons. Emission of coal dust from the coal wagons cause contamination of atmosphere and territory adjacent to the railway track. Different ways to reduce coal dust emission from the wagon are used in the world. Unfortunately, in Ukraine, this problem is far from solution and there is no serious research work in this field. The aim of this work was laboratory study of coal dust emission from the wagon model which had different barriers installed on the wagon. Laboratory experiments were carried for coal wagon without barrier and for coal wagon which had barriers of two types. Barrier of the first type had downwind wing. Barrier of the second type had upwind wing. The contamination zones, concentration near the model were studied. The obtained results illustrate that installation of barriers influence intensity of transport corridor contamination. Also a numerical model was developed to estimate wind flow and coal dust dispersion from the coal wagon. Equation of potential flow and equation of coal dust dispersion were used. Implicit difference schemes of splitting were used for numerical simulation of governing equations. Results of numerical experiment, which were performed, are presented.

Diesel locomotives are widely used at Ukrainian railway stations as maneuvering locomotives. Emissions from these diesel locomotives contain different toxic chemicals. It is important to understand air contamination patterns which are formed at railway stations. Understanding of these contamination patterns allows to evaluate the negative impact of diesel locomotive emissions on environment. To solve this problem it is necessary to use mathematical models which take into account the most important factors influencing formation of contamination zones. This paper introduces numerical model which allows to simulate pollutants dispersion from moving diesel locomotive. Developed numerical model is based on three dimensional equation of potential flow and three dimensional equation of pollutant dispersion. The model takes into account pollutants (NO, NO₂) chemical transformation. To solve three dimensional equation of potential flow the implicit difference scheme of splitting was used. To solve three dimensional equation of pollutant dispersion the implicit difference scheme of splitting was used. Euler method was used to solve numerically equations of pollutant chemical transformation. Developed numerical model allows to take into account influence of buildings at the railway station on the contamination zones formation. Developed model consumes not much computer time. Results of performed numerical experiment are presented.

JSC "Ukrzaliznytsia" purchased the first of three planned regional three-car (two main motor cars and one intermediate) diesel train DPKr-3 manufactured by PJSC "Kryukovsky railway car building works". To confirm the declared characteristics and safety indicators of the DPKr-3 diesel train, specialists department of Cars of Dnipro National University of Railway Transport named after Academician V. Lazaryan conducted complex certification tests, which confirmed the compliance of the stated parameters. One of the points of the Terms of Reference was to determine the brake pressure of the linings per 100 weight of the train in terms of cast iron brake pads. For this purpose, according to the methodology adopted in the territory of the former CIS, force sensors, which were installed in the tick mechanisms instead of the brake linings, measured the magnitudes of the forces of pressing the brake linings on the disks. However, during the tests it was found out that the current standards for calculating the provision of train brakes cannot be applied to modern rolling stock. It is recommended for rolling stock where the use of brake pads, and even more cast iron, is not provided by the design, to develop normative documents that would determine the standards for brakes by the results of calculations and tests.

Application of high-voltage frequency converters is one of the most prospective trends in the development of current powerful electric drives, i.e. in high-speed trains. In terms of such converters, a multilevel cascaded H-bridge converter is becoming the most widespread one owing to its increased reliability, survival in terms of one or more damaged cells, and quick repairability due to its modular structure. The research proposes a control method, which provides maximum possible linear voltage in case of one or several damaged cells owing to the shift of zero point and turning of phase voltages. It is also demonstrated how turning angles of phase voltages should be set to preserve spatial position of the linear voltage vectors which provides the least complicated electromagnetic transients in terms of nominal rotation frequency; in case of low or middle frequencies, damage of the cells may have no effect on the motor operation. Fast algorithm to calculate turning points of phase voltages is proposed; the algorithm may be applied in the industrial microprocessor control systems. Algorithm of the operations, which provides implementation of the method, is described.

The current article is devoted to the topic problem of decision making concerning the choice of the protective means for asynchronous motors operated within industrial shop electric circuits under challenging conditions of improper electric supply. In this paper we show how energy economizing model for the asynchronous motor can be presented in the form of predicate disjunction and be applied with the pattern recognition algorithm for making solutions. The major advantage of a new model is its open character and the possibility of knowledge accumulation with respect to electromechanical equipment. We submit the information on the software and hardware complex applied for the research on the characteristics of the circuit voltage and the asynchronous motors in the real time mode directly within the enterprise industrial shop. The publication also reports on the searching for the best protective solution for asynchronous motors. This work is based on the known recognition algorithm of statistical optimization for non-linear objects given as the aggregates of predicates. The algorithm fruitfully applies the local selection principle. The approach proposed in this publication has been approbated at the protective means selection procedure for the asynchronous motor of 7.5 kW capacity, which performance is 80% of the working cycle under conditions of improper electric energy supply in the experimental shop of Ukrspetsservis.

In case of some accidents on railways there may be situations when the shock wave appears and interacts with different objects on the railway (wagons, cargo, buildings etc.). In these cases it is necessary to predict the possible effect of shock wave diffraction on the different objects. Study of these problems on the basis of physical experiments (laboratory experiment or field experiment) demand expensive and unique experimental facility. In some cases physical experiment can't be set. That is why mathematical simulation plays the important role in solving problem connected with shock wave propagation. For practice it is necessary to have predictive quick computing mathematical models which allow to perform numerical experiment on the basis of non-powerful computers. Now, in Ukraine, there is a real deficit of mathematical models which allow to compute quickly shock wave interaction with different objects. The aim of this work was development of quick computing numerical model to simulate shock wave propagation and its interaction with the wagons. The model is based on the numerical integration of Euler equations which are written in integral form. To solve modeling equations difference scheme of splitting was used. Results of numerical modeling are presented.

The paper aims to the topical issue of improving the system in the planning of carriage of dangerous goods by rail subject to ensuring a high level of safety of the transport process and minimal costs for its implementation. Formalization of this process leads to the formation of an optimization task of the two-stage mathematical model. To implement the first stage, a mathematical model in searching the best route based on risk minimization is developed. In order to exclude the unacceptably complex and expensive options for the carriage of dangerous goods from the many possible routes, the authors abided by the condition not to exceed the critical operating costs. The second stage in the process of planning routes for dangerous goods takes into account the hazard identification study in the technological process of car movement with dangerous goods. Considering that the probability of a potential traffic accident is a complex random variable, which is due to a set of elementary previously unknown events, its estimation was made on the basis of the Bayesian approach. Based on the simulation results, the following reliability values are determined at which a transport accident should not emerge.

The paper is devoted to a theoretical study of the car movement stability when exposed to longitudinal forces of a quasistatic nature. The authors obtained the expressions for calculating the resistance coefficient of the car lift by the longitudinal compressive force acting on the car as part of a freight train. The influence of some factor's combination on the longitudinal forces, at which the car movement stability is still maintained, was analyzed using the analytical dependencies to assess the longitudinal loading of cars in trains. The study was carried out by analytical method for assessing the freight car stability when moving at different speeds along curved track sections. The calculations were made in a curve of small radius taking into account the inertia forces from the unbalanced acceleration. In a theoretical study, the influence of quasistatic longitudinal compressive forces depending on changes in speed and force value, as well as the influence of friction in the wheel flange and rail contact and the eccentricity of fastening the automatic coupler shank on the stability were considered. When applying the results obtained, the stability of freight rolling stock can be increased, which in turn will remove some existing restrictions on the permissible speeds and increase the technical speed of train movement. Using the described methodology for determining the lift resistance coefficient will make it possible to justify the cause of derailment, as well as to develop and put into practice technical measures to prevent the lift of carriages, thrusts and shears of the track.

The article discusses one of the options to reduce the electricity consumption for the carry out acceptance of post-repair tests of traction electric machines. Heating tests of traction electric machines at the mutual load stand are the most energy-intensive part of the entire test program. Energy consumption for this type of test can be reduced, for this, an analysis of thermal processes in the windings of traction electric machines during their heating test was given. The energy efficiency coefficient of the mutual load system is formulated. The energy efficiency coefficient for the traction electric machine NB-406 is calculated. The calculation results showed that with an increase in the test current by 30%, the total losses in the motor windings decrease by about one and a half times, while the test time decreases by almost three times. An increase in test current and a decrease in test time do not reduce the quality of the test, and the results obtained. A methodology for assessing the energy efficiency of heating tests is proposed. It can be applied at test sites of depots, as well as repair plants. This will reduce the material costs of testing, without compromising the quality of the tests themselves.

A mathematical model of the inter-car connections used in the long and heavy train is presented. It takes into account the elastic-frictional properties of absorbing devices and gaps in automatic coupler devices connecting the train cars. There are demonstrated the calculation results of a homogeneous train motion along a straight horizontal track section at such non-steady modes as at starting, braking by the locomotive electrodynamic brakes and passing along a track profile section of a complex shape. A comparative assessment of the influence of the kind of the absorbing devices power characteristic on the maximal longitudinal forces arising in the train inter-car connections is carried out using the MSC ADAMS engineering software package. Transients with a smooth and sharp change in traction and braking forces are considered. Based on the obtained results, the main positive and negative properties of rigid, linear and soft power characteristics of the automatic couplers' absorbing devices used on the railway rolling stock are determined. The results of performed computer simulation can be applied to the sphere of design and modernization of absorbing devices of automatic couplers and to the process of composition of various types of cars in trains of any length and weight.

The article assesses the long-term strength of the vibration damper assembly of a double power transmission of electric trains manufactured by «Hyundai-Rotem Company». The technique is described and the analysis of the service life of the elements of the chassis of the electric train is made. The presence and nature of micro cracks in the loaded elements of the vibration damper assembly was evaluated after a full cycle of vibration bench tests. The influence of vertical vibrations of the electric train body on the level of dynamic load and the service life of the bearing elements of the vibration damper assembly is considered. The service life of the vibration damper at the end of the service life has been estimated by comparing working hours and "statistical playback". The calculation of the resource by the method of "statistical reproduction" confirms the possibility of operating the vibration damping module (second modernization) for 50 years from the date of construction. The influence of the vibration damper position on its dynamic loading is checked. The main stages and sequence of tests for estimation the resource of the longitudinal vibration damper module of a double-fed electric train are also considered, including methodological, calculated and experimental confirmation of the reliability and durability of the unit, which was studied as part of a comprehensive work.

Transportation of goods in large containers with loading length of 80 feet is one of the promising directions of railway transport development. However, despite considerable experience in construction of long-wheelbase flat cars, occasionally problems with the strength of load-bearing elements arise at the calculation, design and manufacture of such products. The article presents the technical characteristics of a long wheelbase flat car, as well as the results of experimental studies of fatigue tests of its load-bearing elements. The optimization of the design of the long wheelbase flat car was achieved both by increasing the sizes and shapes, and by using materials of increased strength. An analysis of the study's results of an improved design showed the compliance of the values of the safety factor of fatigue strength and the service life of the flat car with regulatory and technical documentation. The conducted studies allow us to make recommendations regarding the design, rebuilding and testing of long wheelbase flat cars. The primary results of fatigue tests of the main load-bearing structural elements within the scope of experimental studies turned out to be mostly below acceptable values. This article contains facts confirming it. The results of experimental studies to determine the fatigue strength proved that the design elements require improvement and strengthening.

Tests and research can be greatly accelerated by applying a multi-point load to the test wheel. The aim of this work is to substantiate rational parameters of the stand for accelerated life tests of railway wheelsets, in which a multi-point load applies to the rolling surface of the test wheel. On the basis of the laws of the theory of elasticity, we performed analytical calculations of the contact stresses created by the rolling bodies of the load mechanism of the test stand. Research has shown that the dependence of the contact stresses on the wheel rolling surface on the ball's diameter is nonlinear. The decrease in stress is due to an increase in the contact area. We obtained the analytical and graphical dependencies, which make it possible to evaluate the influence of the parameters of the stand for accelerated life tests of railway wheelsets on contact stresses on the wheel rolling surface, taking into account the shape and dimensions of this surface. The authors have proposed a stand design for accelerated life tests of railway wheelsets. The use of a stand with the parameters justified in this work will reduce the test duration by 10-15 times.

Due to changes in the characteristics of the fuel equipment during operation, a considerable part of the life cycle of locomotive engines operate under increased fuel consumption, and thermal voltage, which often causes degraded environmental performance and reduced engine capacity and, as a result, low efficiency of the locomotive. A reserve for improving the performance of the diesel plant and the diesel locomotive in general is the implementation of measures to prevent changes in the characteristics of the fuel system, for example, the development of clean-in-place technique of fuel systems from carbon deposits. In order to determine the effectiveness of such measures, it is necessary to apply new quality control methods of fuel atomization. The article offers a more informative method for evaluating the quality of fuel atomization, which can be used in locomotive depots during research and development work. The method consists of microphotography of the drops of sprayed fuel followed by microscopic analysis and processing of the results using special software. It is proposed to process the results of injectors testing using a statistical method, taking into account the parameters according to the Rosin-Rammler dependence for the relative total curve. As a result of the work, it became possible to develop requirements and implement technical improvements to the test stands for fuel equipment of diesel locomotives.

In the article a comparative analysis of existing methodologies and approaches on the parameters determination of the capacitive energy storages for a metro train with energy recovery systems was performed, disadvantages of each of them were determined. A complex approach for estimation of the on-board capacitive energy storage parameters was proposed; the point of approach consists in determination of the rational power and energy capacity for two parameters of the storage system at once – mass and payback period. The complex approach is based on theoretical researches, which require simulation of the metro train equipped with recuperation system operation by mean of developed software. The objective function was represented and boundary values for the power and energy capacity during determination of the rational parameters of the on-board capacitive energy storage using a complex approach were specified. The recuperation system with rational parameters of the on-board capacitive energy storage for specified service conditions in Public Utility Company "Kyiv Metropolitan" and chosen research metro train was specified. Amount of energy stored due to the installation of the energy storage system with rational parameters was estimated.

The aim of this work is to theoretically determine the total resistance to soil pricking with a wedge-shaped tip to create a rectangular cavity and to determine the influence of the size of the working equipment and soil environment in the repair of earthenware or areas where trench technology can-not be used. To determine the forces of the recess of the replaceable pilot, the law of change of soil pressure on the working surfaces of the working equipment was first determined, which is based on the idea of the change of the soil elastic state at its compaction was determined, which is determined by the compression module of deformation of the soil. The processes occurring during the formation of wells and new approaches to the improvement of calculations have been described. On the basis of the pro-posed model of the piercing process, the laws of change of the normal pressure of soil resistance on the surface of the wedge working equipment are established. Based on its value, the results of theoretical studies have received a rational form and parameters of the tip of the work equipment.

The goal of the article is to evaluate the possibility of improving the design of an open wagon body in order to improve traffic safety when transporting cargoes whose height is beyond the upper belt of the side wall (cargo loading with a "hat"). To achieve it, the authors have proposed a variant of a pull-out bar in a wall rack. In lazy state such bars located inside racks, but during transportation of timber, pipes etc they are pulled out above the wall upper belt to prevent cargo from rolling out. These bars are quite light (mass of one pull-out bar is equal to 3 kg, that corresponds to 36 kg of an additional equipment per a wagon), but they considerably facilitate fixing cargo in an open wagon replacing additional wooden fixing racks. It also makes the transportation more reliable due to elimitation the possibility of skew and jamming of fixing equipment. Strength of the proposed element and the entire wagon side wall is estimated with the finite element method. The proposed bars withstand normative loads, and holes in the upper belt for them do not lead to desrease of the wall carrying capacity.

The article presents the main results of a theoretical study on the analysis of the stress-strain state of the construction of the buffer bar of the electric locomotive for the control of the traction unit PE2U. The estimation of the possibility and effectiveness of attachment on the front wall of the buffer beam of a special securing bracket was considered as a separate task. In both cases, the finite element method based on the SCAD for Windows computing system was used. As a result, it was found that in general, the design of the buffer beam does not meet the requirements of the current standards. Up to 5 zones of high stress concentration are present in the structure, which, given the long service life of the machines (up to 40-50 years), are potential places for the development of fatigue damage. In order to balance the stress level, we recommended to strengthen the contact zone of the supports under the automatic coupling with the system of horizontal truss plates. The additional recommendation is to reinforce the lower sheet of the buffer beam structure up to and including its replacement by a sheet of greater thickness. Attachment to the front wall of the buffer beam of a special securing bracket for holding in emergency mode the coupling of the locomotive-car is possible provided that this zone is strengthened by the system of additional truss plates. The total increase in the mass of the buffer beam reaches 350 kg (25 % of the original weight of the buffer beam structure).

The formation of structure and properties of thermal coatings is largely determined by the transformation intensity of sprayed materials at all stages of obtaining of coating. It is shown that during D – gun spraying, in order to ensure optimal conditions for leading transformations and phenomena that have a decisive influence on structure and properties of sprayed coatings, composition of combustible mixture, geometry and dimensions of barrel, conditions for introducing powder into the barrel and a unit dose of powder, spraying distance, timing of spraying cycle and other technological methods can be used. The possibility of transformation in powders of tungsten carbide and chromium under different methods of thermal spraying is analyzed and the structure and properties of coatings are obtained. The influence of the conditions of D – gun spraying on spraying distances, gas flow rates, type of powder, etc.; phase composition and properties of coatings is studied. The basic physicochemical transformations that accompany D – gun spraying of coatings of alloy WC – C, such as oxidation and reduction of tungsten carbide in high – temperature oxygen – containing media, interaction of composite coating components are considered problems of modelling of bonding of particles with a part surface during thermal spraying of coatings are considered.

The problems of modelling of bonding of particles with a part surface during thermal spraying of coatings are considered. The formation of adhesive and cohesive strength of thermal coatings is considered from the standpoint of the theory of welding of materials in solid phase. The formation of interatomic connections between particle materials and parts is accompanied by deformation processes in contact zone, which facilitate the unloading and rupture of connections in the metal – oxygen system, loading and connections between atoms of interacting materials. The kinetics of formation of interatomic connections between materials of particle and substrate at high collision velocities is satisfactorily described by a modified semi – empirical equation that uses experimentally measured quantities: the magnitude of tensile deformation of interatomic connection, the Young's modulus, the coefficient of thermal linear expansion. Possible influence of nanotopography of substrate surface on the interaction with sprayed particles and formation of coatings with high adhesive and cohesive strength is shown.

The motivation of the research and further development of the new type combined knife system on the non-return bulldozer blade and the results of the first series of laboratory studies of the process of the soil digging with the non-return blade of the bulldozer with the first set of its physical models, which indicate the feasibility of continuing research in this direction is given. The proposed combined knife system makes it possible to realize oblique digging of the soil on the non-return blade of the bulldozer and maximally complete its orientation in the prism of the soil before the blade in order to increase the productivity of the bulldozer with non-return blade by decreasing soil losses in the side rollers, decreasing the time of filling and digging the soil by decreasing the coefficient of specific soil resistance to digging. The paper substantiates the technology of more efficient use of bulldozers with non-return blade compared to their traditional counterparts, which is possible due to the use of the new combined knife system, and argues in favor of expanding the technological capabilities of the bulldozer with non-return blade, equipped with the proposed engineering solutions of the new type knife system with different digging angles and spatial inclination of cutting edges.

The directions of combination of working bodies in the existing soil compactors and machines of the new generation and the technologies of their application for productive and effective soil compaction of the lower track structure, soil structures of roads and other construction objects are given. The basis of the research is the principle of accelerated soil compaction due to the creation on the surface of the contact with the working bodies of the sealing machines pressure, which exceeds the limit of plasticity of the soil and at the same time limiting the slipping of the sides from under the working sealing surface. It is proposed that the working sealing surface modular type that can change its profile depending on the technological requirements. Further research is aimed at creating the required profile of the working body based on the desired compaction core and the structural formula of the working body of the soil compactor. In this case, replacing the elements in the working bodies with the corresponding mathematical models, we obtain a common mathematical model of the working body of the soil compactor, as well as the profile of its working body, based on the specified energy consumption and technological requirements.

A new method to create of the plane section standards of grain metal structures with a previously known size distribution of 3D grains is proposed. A quantitative analysis of G3, G4, G5 indices of the standard ISO 643:2012 was performed. The stereological modeling method taking into account the polyhedral shape of 3D grains was used to create new versions of plane section standards. Versions of 3D grains structures as the diameter size distributions of 3D grains, plane sections of which correspond to the main quantitative characteristics of existing G3, G4, G5 indices have been created. It was shown that these versions should contain 3D grain more than 1.5 times the mean diameter of the corresponding plane sections. Choosing the diameter size distributions of 3D grains, necessary for the standard, its possible to create a visual index as a picture, as it done on the existing standard, and also to give the parameters of 3D structure, plane section of which corresponds to this standard. Using a new approach to creating standards will increase the accuracy of the grain structure parameters determining.

The objective of the study is research into psycho-physiological methods of control over the functional status of a person for higher efficiency of a pre-trip control of locomotive crew members. It is related to the fact that today's medical methods do not reveal some states which decrease a functional reliability level, particularly, a fatigue level and borderline states. The authors selected parameters which, according to the functional system theory, give information on conditions of two regulation levels in the human body, physiological and higher nervous activity, and correspond to the formulated requirements in terms of the procedure. The study experimentally proved the informative value of 27 psycho-physiological parameters for estimation of exhaustion and borderline states. For a state of exhaustion the hemodynamic parameters, including those of arrhythmia, both sinus and slow waves, were of the most informative value. The study revealed the parameter of arterial pressure pulse, the value of which in the post-trip group decreased by 25%. While identifying existence of borderline states by sinus arrhythmia parameters, it turned out that much more people with borderline states were in the exhaustion zone, rather than in the control group (42% and 16% respectively).