Introduction. Diesel generators sets are commonly used to power the refrigeration units of autonomous refrigerated cars. In order to increase energy efficiency of autonomous refrigerated cars it is proposed to switch from diesel fuel to liquefied natural gas (LNG), with transition from diesel fuel to LNG and introduction of cold recovery units from LNG regasification for additional cooling of cargo area in conjunction with the main refrigeration unit. This transition necessitates a comprehensive assessment of the potential for utilising the physical exergy available during the regasification process. The aim of the study is to determine the thermodynamic limits and justify the selection of operating parameters for LNG cold energy recovery in the auxiliary cooling circuit of the cargo compartment.Materials and methods. The study employed numerical thermodynamic processes simulation of an open regasification cycle for LNG fuel. Energy and exergy analyses, along with the heat balance method, were utilised. Key indicators, including specific cooling capacity and second-law exergetic efficiency relative to the Carnot cycle, were calculated.Results. The authors examined LNG cold recovery scheme based on an open cycle with a cryogenic pump. The results of the numerical simulation of the thermophysical regasification processes are presented. The dependencies of specific cooling capacity and exergetic efficiency on operating pressure were evaluated, and parameters ensuring the prevention of LNG boiling outside the recovery circuit were determined. It was established that pressure increase in the regasification line significantly enhances the thermodynamic efficiency of the system with negligible reduction in enthalpy potential.Discussion and conclusion. Exergetic efficiency criteria for autonomous systems were formulated, enabling a transition from an enthalpy-based to an exergy-based assessment of LNG recovery potential. A rational range of operating pressures was identified, achieving a thermodynamic optimum for cold recovery. This operating mode is essential for ensuring the hydraulic stability of the fuel supply system, simplifying the refrigerated car design and unifying the fuel supply scheme during the transition to LNG usage.
Introduction. Due to the redirection of key logistics flows in Russia to the East (Asia Pacific), increasing throughput capacity of the Trans-Siberian Railway is an urgent task. Addressing this challenge requires a comprehensive assessment of the state of railway transport infrastructure facilities. The aim of this study is to analyse the operational characteristics and determine the maximum throughput capacity of the railway station located in a mountain-pass section of the TransSiberian Railway, which acts as its bottleneck. The authors proposed and applied an original comprehensive tool for railway station operation modeling, which enables to increase the reliability of the research results.Materials and methods. Simulation was employed as the main research tool. In order to enhance the reliability of the results, two alternative approaches were applied. The first is based on the use of AnyLogic software. The second relies on queuing theory, with the development of the authors’ own software and algorithmic framework.Results. Two complementary simulation models were developed and used to conduct computational experiments. Based on the results, a scenario analysis of the station operation was performed, including the determination of efficiency indicators for various headways.Discussion and conclusion. It is established that the considered station is capable of handling train traffic with headways of 11 min or more. Station reconstruction would be required to reduce it. The queuing theory mathematical apparatus may be used to study railway stations operation, which reduces the complexity of model construction and analysis.
Introduction. In the context of the global digital transformation of railway transport and the transition from discrete parameter recording to the creation of digital twins of energy systems, it has become increasingly critical to implement systematic modernisation of Automated Information and Measurement System for Commercial Electricity Metering of JSC “Russian Railways”, in order to close technological gaps and ensure predictive control of energy consumption and the technical condition of equipment. The purpose of the work is the development and theoretical justification of the target architecture for a unified model of a digital platform integrating functions of legally significant commercial metering, predictive analytics (forecasting of electricity consumption and equipment failures), interaction with corporate systems, and external intelligent power grids.Materials and methods. The research is based on a systematic analysis of the architectural-functional structure of the existing Information and Measurement System. Methods of structural modeling, comparative analysis of accounting subsystems and metering equipment fleet were used. Regulatory and legal framework was analysed, and a critical review of scientific publications was conducted.Results. The study identified key limitations of the existing Information and Measurement System: technological fragmentation, diversity of equipment fleet, insufficient level of reporting automation. Weak integration with the corporate software environment and low rates of adaptation to the concept of intelligent power grids were noted. The current infrastructure does not provide monitoring of energy distribution from source to consumer and lacks predictive analytics functionality. The obtained results served as the basis for forming the target model of a unified digital platform. A four-level architecture for the system is proposed.Discussion and conclusion. The necessity of transitioning to a unified digital platform integrating predictive analytics functions and seamless interaction with various systems is substantiated. The proposed solution creates a foundation for developing digital twins of energy objects, reducing operational costs and commercial losses.
Introduction. Wagon turnover time change is commonly estimated by the location of wagons at sites, technical stations, public and non-public railway tracks, in local downtime. Experience shows that exclusive use of these data leads to inaccuracies and errors. The purpose of the study is to propose a new refined methodology for analysing the indicator of the wagon turnover time, and to show the influence of the calculated parameters included in it. The application of the methodology would allow to develop effective measures to accelerate turnover and improve the quality of the transportation process.Materials and methods. Statistical data of railway transport operations for freight transportation in 1995–2024 are used. The main theoretical results are obtained based on algebraic transformations of dependencies linking the change in wagon turnover time with the change in the values of calculated parameters in various time periods.Results. The authors developed a methodology for determining the change in wagon turnover time with in-depth details for various calculated parameters, which is used to analyse the influence for each of calculated parameters on the change in wagon turnover time in 2010–2024 for railway network. This period in characterised by the transition from stable values of the wagon turnover time with a general downward trend to a period with significant fluctuations with a significant upward trend, approximately in 1.5 times. This caused an increase in the required car fleet by more than 350 thousand wagons, excessive occupation of station tracks and difficulties in train traffic passage. The share of each calculated parameter in the growth of wagon turnover time and their rating for reducing the impact on the overall indicator have been established.Discussion and conclusion. The developed theoretical proposals allow for a more accurate assessment of the causes of changes in wagon turnover time and provide a basis for making decisions aimed at improving the operation of proving grounds and railway network as a whole.
Introduction. The aim of the paper is to substantiate a set of measures to improve the efficiency of transit train handling in conditions of freight traffic increase. Currently, it is relevant to increase the traffic capacity to achieve the calculated effective mode of operation of the railway, which is provided when the available capacity is equal or greater than the required capacity.Materials and methods. The paper considers options for organising freight trains movement in the entire range of ratios between required and available capacity. At the same time, it is possible to move a significant number of trains according to mixed indications of traffic lights signals — green, yellow, red, and at lower speeds.Results. Obtained analytical ratio shows a decrease in the average speed of freight trains, depending on the permissible train speeds at yellow and green traffic lights, and the distance between the following trains. According to the basic ratio for the average speed, the distance between trains from two to three block sections, fundamental dependence of the average speed of freight trains on the yellow-green traffic light signals on the number of trains is obtained using the example of a 180 km long section, 3 km long block sections, and the accepted speeds for green and yellow at 80 km/h and 40 km/h. Analytical dependences of the section speed on the length of the section, on the average speed of freight trains and on the magnitude of delays in each movement are obtained.Discussion and conclusion. The calculations show a significant effect of reducing the distances between trains and increasing the amount of delays on the reduction service speeds and explains the decrease in section speeds observed in practice on heavy-traffic routes down to 32–35 km/h.
Introduction. Freight car fleet is a crucial production and economic asset for railway transport. Its effective utilisation is a major focus in both industry research and practical applications. Therefore, a relevant analysis of freight car utilisation is essential for developing strategies to improve it in modern environment. This, in turn, necessitates refining the methods used to evaluate the effectiveness of the freight car fleet. The purpose of the article is the analysis of existing approaches to assessing the use of freight cars and proposal development for its improvement.Materials and methods. This paper examines the conventional approach to evaluating freight car utilisation and alternative approaches proposed in academic literature. The article emphasizes the need to enhance the methodological tools used for assessing freight car utilsation.Results. A novel approach to assessing freight car utilisation is proposed, using the “temporal capacity of freight car mileage” indicator. Component and marginal analysis of this indicator is conducted, considering data from a long-term historical perspective.Discussion and conclusion. Comparison of the dynamics of the temporal capacity of freight car mileage with other indicators of car fleet utilisation reveals that the new indicator effectively reflects the actual acceleration or deceleration of freight car turnover. Its application enables an accurate evaluation of the freight car fleet utilisation and the potential for improvement. This necessitates improvements in car flows organisation and implementation of innovative technologies for station and train operations. Simultaneously, a decrease in the temporal capacity of freight car mileage may serve as a cost indicator for implementing identified improvements and as a benchmark for evaluating the success of these strategies.
Introduction. The thermal performance of the passenger car body is strictly regulated, their deviation from the norm leads to a significant excess energy consumption, which is reflected in an increase in the cost of passenger transportation. Over time, due to different operating conditions and ranges, the value of the heat transfer coefficient becomes individual for each production carriage body and heat losses through carriage body guards. The purpose of the article is to develop a new methodological approach based on the heat transfer coefficient of enclosing structures, which would enable to assess the thermal condition of the carriage body with less labor intensity, more quickly and both during the factory production of the car and after its commissioning.Materials and methods. Calculations of the values of the heat transfer average coefficient of the enclosing structures of the carriage bodies at train stand were performed based on the results of thermal engineering tests of passenger carriage bodies using the standardised method of equilibrium modes, as well as the method of nonequilibrium modes.Results. Comparison of the calculated values of the heat transfer average coefficient bodies of four passenger carriage bodies, obtained as a result of a series of thermal engineering tests using a standardised method with similar values calculated according to the method of nonequilibrium modes, did not exceed 3%.Discussion and conclusion. When conducting thermal engineering tests of passenger carriage bodies based on the method of nonequilibrium modes, the value of the average heat transfer coefficient of the enclosing structures of the car could be determined in production conditions in 11 h without compromising accuracy, which is 7–8 times faster than the currently used standardised method. The use of nonequilibrium mode methods enables to organise control of the normative thermal technical indicator of the carriage body after car commissioning throughout the life cycle, which gives opportunities for planning the volume of car fleet energy consumption.
Introduction. Containerisation growth and changing geography of cargo traffic flows under current challenges necessitate improving the efficiency of cargo container terminals. To date, existing approaches to digitalisation fail to account for technological and operational differences among container terminals, which leads to the implementation of excessive functionality and unjustified costs. This study aims to develop a classification of cargo container terminals that establishes minimum requirements for the digitalisation of production processes based on workload and operational technology.Materials and methods. The author employed mathematical methods and analysed statistical data, regulatory framework and technological documentation, which record the current state and established requirements for the operation of cargo container terminals.Results. Data on the operations of railway stations and terminals in the Russian Federation for 2023, regulatory sources, and automation practices of terminals within JSC “Russian Railways” in 2023–2025 were analysed. The revealed key technical and operational characteristics influencing the necessary level of digitalisation are daily container dispatch volume, number of destinations, cargo front capacity, stacking tier height, and type of handling equipment.Discussion and conclusion. Classification of cargo container terminals was proposed, with minimum functional requirements for terminal management systems formalised for each group. Quantitative boundary criteria between groups were developed.
Introduction. At speeds above 250 km/h, significant impact on the way have not only isolated, but also continuous irregularities. The research examines the effect of a specific type of uneven rolling, known as wavy wear of wheel thread described by harmonic functions. The aim of the study is to verify finite element model of wheel rolling along the rail.Materials and methods. Finite-element method is the main tool to investigate the problem in question. The value of equivalent stresses and R65 profile rail displacements at different depth of uneven rolling of wave-type shape at 300 km/h wheel speed was determined.Results. The authors designed finite-element model of interaction between wheel and R65 profile rail, which allows to consider uneven rolling of rail surface, and verified it using analytical dependencies and a similar study. A study was conducted on the effect of uneven rolling on contact force between wheel and rail. Contact force curve between wheel and rail at various depths of uneven rolling of periodic shape is presented. It is shown that force effect from wheel to rail at 300 km/h speed increases by 11 % with a change of defect depth from 0 to 0.2 mm, while displacements and stresses change is less significant (by 8.5 %).Discussion and conclusion. Further validation of the presented finite element model would require its integration with railway superstructure, as well as data on the measurements of the rolling surface and measurement results of their impact on the track. It is also necessary to provide measurements in the direction of rolling circle, since such results are not publicly available. The presented model may be employed for the analysis of uneven wheel rolling effect on dynamic behaviour of high-speed main lines.
Introduction. Train traffic growth, commissioning of commuter trains approximation of residential development to railway lines exacerbate the problem of external noise from railway rolling stock. In order to develop measures, aimed at reducing the external noise level, specialists of the Railway Research Institute, VNIIZhT-Engineering and Scientific-Research and Design-Technology Institute of Rolling Stock jointly conduct comprehensive studies on environmental noise pollution. Since the regulatory framework for external noise as applied to rolling stock is becoming obsolete, it is necessary to update the technical requirements for the main types of electric trains and traction rolling stock. The article provides a brief overview of the conducted work to create a rolling stock external noise classifier.Materials and methods. Field tests, which determined noise characteristics with noise pressure recording, were performed at train stand, as well as in motion at different speeds on tangent level track and in curves.Results. The authors presented and analysed measurements data of the ES1P “Lastochka” electric multiple unit train at train stand and in motion. A database (signatures) of external noise and spectral characteristics of the studied rolling stock has been compiled, based on which a noise classifier of traction rolling stock and electric trains has been developed.Discussion and conclusion. Analysis of the maximum external noise level of the ES1P “Lastochka” electric multiple unit train showed that the influence of rolling stock components on the level of its external noise affects speeds up to 80 km/h, while at higher speeds noise from the contact zones of wheels with rails predominates. The developed classifier would form the basis for further work aimed at localising the increased noise level of specific units.
Introduction. The tasks of car traffic volumes operation in terms of possible changes of service conditions have three solution modes (normative train make-up plan, its periodic changes and operative orders), each of which has its own structure of objective functions, tuning characteristics of controlled variables and constraints, which is the subject of the article. The objective of the article is a formalised statement of the problem and the principal methods of its solution in these modes.Materials and methods. The methods and provisions of the theory of car traffic volumes organisation, the theory of interaction of station processes, set theory, graph theory, and nonlinear mathematical programming are used. The initial data for solving the problems of the car traffic volumes organisation are presented in the form of a structured set of interdependent network models of average daily car traffic volumes and dynamic data on the location of cars. The controlled variables are the sets of goods train destinations and routes, as well as signs of attachment of car traffic volumes to train destinations and train destinations to routes. The objective function is subject to infrastructural, logistical and resource constraints that are interdependent. The objective function of the train make-up plan calculating provides for minimising the average daily cost of promoting car traffic. In the paradigm of the lifecycle of the car traffic volumes operation it is supplemented by a component that considers the cost of transitions between the periods of operation and operating modes of the car traffic volumes organisation system.Results. The need for adjustments to the make-up plan is caused by a change in the flow structure or the availability of resources and is assessed based on a comparison of the working car fleet balance and normative on the railway network division. Depending on this ratio, the authors fundamentally define a set of strategies for finding solutions to normalisation the car traffic volumes organisation system.Discussion and conclusion. The provisions presented in the article are the basis for further structural adjustment of the used economic and mathematical tools for calculating the train make-up plan by the method of step-by-step distribution of car traffic across a network of acceptable train assignments to effectively solve the defined tasks.
Introduction. In this article, a study was conducted focusing on the investigation of fatigue fracture characteristics of elastic clamps used in railway fastening systems, which were subjected to fatigue tests following standard and accelerated methodologies. The problem of improving the quality and extending the service life of rail fasteners, particularly elastic clamps, has become the most acute at the present time. The reason is the development of high-speed and heavy train traffic. In operation, the elastic clamp perceives preloading by mounting force and dynamic loading by cycles of preloading and partial unloading due to the impact of rolling stock. Fatigue life is the most important parameter determining clamps reliability and train safety. The purpose of this study is to analyse the main mechanisms of fatigue fracture of three clamps tested under various cyclic loading modes (according to standard and accelerated test methods) by examining fatigue fracture surfaces.Materials and methods. The elastic clamp CP 369.102 (clamp ZhBR-65) was chosen as the object of the study. The tests were performed using both the standard method that meets the requirements of GOST 33186–2014 and the accelerated Locati method. Fractographic method was used in the analysis of clamps fatigue fracture surfaces.Results. The similarity of processes leading to fatigue fracture has been established for clamps tested using standard and accelerated methods. A fractographic analysis was conducted on the fatigue fracture surfaces of three elastic clamps. An analysis of the fatigue fracture mechanism is provided for each clamp. For the clamp tested by the standard method, a non-metallic inclusion was found at the crack initiation site.Discussion and conclusion. In all studied cases, the fracture of the clamps was accompanied by the initiation of fatigue microcracks originating from inclusions or defects on the lateral surface (the rod surface of the clamp). Current standard does not normalise contamination with non-metallic inclusions intended for the manufacture of clamps. It is reasonable to conduct additional studies in order to assess the influence of non-metallic inclusions in the steel on the fatigue durability of the clamps.
Introduction. Currently, the development of transport highways is strictly linked to urban agglomerations, regional and international logistics corridors, therefore, the urgency of creating multi-level transport interchanges near main hubs is growing. At the same time, it is important to ensure static and kinematic dimensions at various levels of overpasses and underpasses. The article proposes to avoid default usage of beam, arched or truss superstructures and considers a two-support superstructure as an element on which the load from the vehicle is applied to the middle part of the height of the cross-section.Materials and methods. Several standard superstructure designs for automobile and railway transport modes were considered. According to the available engineering solutions, proposals were developed for dividing the cross-section of the superstructure into an upper and lower part relative to the plane of application of the train dynamic load. The stiffness parameters of the superstructure section are represented as a function of orthogonal spatial coordinates. Linearisation method is used as the solution method of the desired functions on elementary time intervals in order to solve the defining differential equations.Results. Dynamic vertical displacements of the superstructure cross-section points are obtained depending on the type of section and the distribution of the stiffness function over height. Variation of the geometric parameters of the bridge span cross-section in the range of permissible values enables to change the maximum movements of the cross-section points to keep them in the line of standard values, which may be in demand during calculation of the structure for the f irst and second groups of limit states.Discussion and conclusion. The presented model is simplif ied and does not consider a number of factors, such as damping in the structural material, irregularities on the surface of the traff ic area and the interaction of the rolling stock wheels with the superstructure. Further research may be aimed at developing more accurate mathematical models that take into account a wide range of factors affecting the dynamic behaviour of bridge crossings. It also seems promising to conduct experimental studies on real structures, which would allow to verify the calculated obtained data and develop practical recommendations for optimising the design of bridge crossings with the distribution of bending and torsional stiffness over the height of the superstructure.
Introduction. The active use of geosynthetic materials in the modernisation of railway track in order to enhance its mechanical stability leads to a significant increase in the electrical ballast layer resistance. This presents challenge for electri- fied AC railways, as it disrupts the normal flow of reverse traction currents and leads to dangerous potential differences between the rail and the ground. The aim of the study is to develop and verify a physical-mathematical model for the as- sessment of potential difference between the rail and the ground on electrified AC railways sections for a quantitative assessment of rail potential and analysis of the effect of the ballast prism structure on its distribution.Materials and methods. In order to solve the problem, the authors developed a refined physical-mathematical model based on the finite element method, which allows to consider the spatial heterogeneity of the electrical parameters of the pipe. The model integrates the resistance of various structural elements of the track: rails, sleepers, ballast and roadbed. Field experiments were conducted on the Experimental Loop of the Railway Research Institute to validate the model.Results. Experimental studies confirmed the adequacy of the developed model. The calculation results demonstrated a high degree of consistency with the field measurements data of the potential distribution along the way. As a result of the work carried out, a tool has been created for solving applied problems related to determining the potential difference between the rail and the ground.Discussion and conclusion. Comparison of the experimental and calculated data of the refined physical-mathematical model shows that the developed model is presented as an effective tool for predicting potentially dangerous sections at the ballastless track superstructure design.
Introduction. Rail damages represented by railhead cracks in the area of joints and bolt holes prevail on railway sections with heavy traffic density and harsh climatic conditions. This is proved by the statistics of withdrawal of severely defective rails on the Trans-Baikal Railway. The analysis of scientific publications shows that in terms of increasing reliability the joint has an advantage with pin and link design of fishplates, which reduces stresses in the rail neck due to the modified support on the rail gorge. The aim of the study is to confirm the hypothesis about the possibility of reducing stresses in the rail neck by using a new fishplate design. In order to confirm the effectiveness of the construction the authors conducted com- parative operational tests with wedge-shaped fishplate construction.Materials and methods. Strain gauge method was used to measure the stress-stain state of the rail neck at the joint. Fishplates were tested at various bolt tightening torques. During tests, the mounting stresses around the bolt hole were recorded first, and additional dynamic loads occurring during the passage of the train were measured after.Results. The results show that the pin and link fishplates reduce the assembly tension stresses in the rail neck and increase the fatigue strength of the rails with an increase in the tightening torque of the butt bolts compared to the wedge-shaped design. Vertical loads have little effect on bolt tightening, and the stresses in the fishplates remain within safe limits. Joint monitoring also confirms the reliability of the pin and link design: bolt tightening torques decrease over time, but no defects or damage have been detected.Discussion and conclusion. The advantages of the pin and link design of a fishplate are proposed and discussed. It is shown that it provides increased reliability of rail joints, reduces stresses in the rail neck and has an increased margin of fa- tigue strength. It was found that this construction retains a higher stability of bolt tightening during operation compared to wedge-shaped fishplates. This increases the durability of the butt joint, reduces the frequency of maintenance, and reduces operating costs. The solution is especially effective for areas with high traffi c density and severe climate.
Introduction. The Eastern Polygon, which covers Trans-Baikal and Far Eastern Russian railways, is characterised by increased freight traffic with an expected growth in the near future. The operation of traction power supply devices in certain areas is associated with a high current load, including reverse traction network. Special measures are required to secure the network and keep it operational.Materials and methods. Rosengartovka – Boytsovo – Bikin section of the Far Eastern Railway was chosen as the research object to assess the impact of joint operation of reverse traction AC network devices and railway automation and telemechanics. The section is located on the main electrified course of the Trans-Siberian railway with an AC traction with 25 kV voltage. Comparative analysis of the effectiveness of the most significant measures in terms of impact on improving the security of railway automation and telemechanics devices was carried out when working with a 25 kV reverse traction AC network.Results. The operation parameters of reverse traction AC network with 25 kV voltage in the study area were determined. The factors of mutual influence on the performance parameters in conditions of real movement of heavy-load trains arising in the operation of the reverse traction network and the degree of their influence on the performance of railway automation and telemechanics devices are estimated.Discussion and conclusion. According to the results of the research conducted on the section of the Far Eastern Railway, evidence is provided on the possibility of increasing the critical voltage of switching devices up to 2500 V. Technical measures were developed and classified to minimise the impact of 25 kV reverse traction network modes on the operational performance of railway automation and telemechanics devices, indicating the degree of their impact and evaluating the achieved effect.
Introduction. The article considers the issues of improving the operation of equipment for vibration diagnostics of rotary mechanical units of rolling stock, and determining objective criteria for assessing the efficiency of the diagnostic process. Industry regulatory documents have significant shortcomings in terms of determining the efficiency indicators of diagnostic equipment. Examples of calculating the “certainty” indicator, performed using different methods, showed that the results of calculating this indicator depend on the sample size of the diagnosed units. The purpose of the article is to analyse existing methods for assessing the quality of operation of vibration diagnostic equipment and to develop an additional criterion for assessing quality based on the likelihood function.Materials and methods. The samples of diagnostic results of axle boxes of wheel pairs of wagons (selected as an example) are the source material for the discussed problem. The employed methods relate to the sections of mathematical statistics and probability theory. A mathematical method for estimating parameters based on the calculation of the likelihood function is analysed. An example of calculating the likelihood function on simulated data is given.Results. The result of the work performed is a methodology that allows to determine the certainty limit of diagnostic results of a given degree of probability (“reliability”).Discussion and conclusion. The authors propose to introduce interval estimates of the “certainty” parameter. It is proposed to use three intervals with specific boundary values. Along with the assessment of the certainty (confirmability) of diagnostic results the authors propose to assess the quality and efficiency of operation of vibration diagnostic equipment by calculating the likelihood function. It is noted that the results of the study could be used in various industries.
Introduction. The authors conducted valid accounting methods choice of complex stress-strain state and mean stress in the calculations of elastic clamps of intermediate rail fastenings nodes connected with the localisation of potentially critical sites under the condition of fatigue durability. Methods that enable to most accurately localise places of fatigue fractures has been determined.Materials and methods. The elastic clamp CP 369.102 (clamp ZhBR-65) was chosen as the clamp under study. The selection of potential methods for accounting complex stress-strain state and mean cycle stress for the origin of a fatigue crack in an elastic clamp localisation was carried out through a review and analysis of existing approaches. A finite element model of the elastic clamp was developed for conducting virtual tests. Full-scale fatigue tests of the elastic clamps were performed according to the developed test procedure. In order to compare the results of the full-scale fatigue tests and the virtual experiments, 3D scanning of the fractured clamp fragments was employed.Results. It was established that samples of the elastic clamp CP 369.102, when subjected to full-scale fatigue life tests, failed in two distinct zones with probabilities of 5 % and 95 %, respectively. The results of calculations performed using combined methods for accounting complex stress-strain states and the influence of mean cycle stress demonstrated satisfactory correlation with the experimentally determined locations of fatigue crack initiation in the clamps.Discussion and conclusion. Combinations of methods for accounting for complex stress-strain states and the influence of mean cycle stress were identified, which allow to localise potentially critical zones of the elastic clamp in terms of fatigue durability during calculations. Further research is planned and aimed at developing a model for the elastic clamp that would enable a sufficiently accurate assessment of its service life based on the current results.
Introduction. The article examines the key scientific and technical problems arising at design and construction of the KS-400 overhead contact line for Russian high-speed railways and presents their solutions based on the results of numerical simulations and stage-by-stage tests. At high train speed, electric current loads increase and dynamic interaction between pantographs and catenary becomes more complex. To provide a required quality of current collection, an extensive study of the parameters affecting mechanical, electrical and thermal processes in the pantograph-catenary interaction system must be carried out. The aim of the presented study is to ensure reliable operation of the overhead contact line assemblies and components in the wide range of operational conditions.Materials and methods. Numerical simulation methods have been employed in the design of the KS-400 overhead contact line. The contact line is simulated with a detailed finite element model and the pantographs are modeled using multibody dynamics approach. Numerical models employ a three-dimensional nonlinear formulation. Dynamic problems are directly solved in the time domain by numerical integration of the system of finite element equations over time. Contact interaction between catenary and pantographs is modeled using the penalty method. The compliance of the overhead contact line parameters and the individual hardware components with regulatory requirements is confirmed by mechanical, electrical, thermal and other types of tests.Results. The KS-400 overhead contact line assemblies and components have been designed based on the results of numerical simulation. It has been shown that the obtained indicators of current collection quality are within the allowable margins. The main technical solutions for the KS-400 overhead contact line and the key stages of its design and construction are presented in the article.Discussion and conclusion. To date, large amount of design, research and development work on implementing the KS-400 overhead contact line for Russian high-speed railways have been carried out. The prototype hardware components have been manufactured. A pilot overhead contact line section has been built at the Experimental Loop of the Railway Research Institute. The tests due are currently underway. In order to confirm operational compatibility of the KS-400 with other railway subsystems and to check the quality of current collection at high train speed, further field tests are scheduled at the Kryukovo – Novaya Tver experimental site which is a part of the designed Moscow – St. Petersburg high-speed railway.
