Freight Car Research Articles

Improving Freight Train Wheel Monitoring with Smart Sensors

Onboard monitoring of freight car axleboxes enhances safety, reduces maintenance costs, and improves track conditions by preventing secondary damage. Installing wireless sensors on freight cars without a nearby power source should be cost-effective, given the large quantities involved. To address this, a new wireless smart sensor node has been deployed. The sensor automatically recognizes stable operating conditions, detects wheel rotational speed from vibrations, performs real-time condition monitoring, and transmits the results to the cloud. This study outlines the smart sensor concept and the pilot field test conducted with real freight cars. The results demonstrate the ability to estimate wheel rotational speed from vibrations and the potential for detecting wheel out-of-roundness (OOR) using a newly developed condition indicator for low-power real-time operations.

Oновлення парку рухомого складу українських залізниць з орієнтацією на інтеграцію в європейські транспортні мережі

The strategic aim of further development of the Ukrainian railways is rolling stock and infrastructure renewal to meet the demands of the Ukrainian economy, including a rapid integration into the European transport service. The paper presents the results of recent studies conducted at the Department of Statistical Dynamics and Multidimensional Mechanical System Dynamics, the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, with the aim to solve important problems in the development of the Ukrainian railway transport. The studies were aimed at developing scientifically substantiated decisions on Ukrainian rolling stock renewal oriented at integration into the European railway networks. To do this, a cycle of theoretical and experimental studies was conducted at the department. Consideration was given to the problem of wheel–rail contact pair improvement by identifying a wheel profile that would offer an acceptable car ride performance and acceptable conditions of car–rail interaction both on the Ukrainian and the European railways and reduce vehicle and rail wear. The car ride performance of an articulated passenger train was simulated mathematically for its motion at different speeds along a track of arbitrary alignment and profile, and the effect of different car and track parameters on the ride performance was estimated. Energy-absorbing devices were developed to increase the passive safety of a speedy locomotive-hauled passenger train and a multiple-unit train in emergency collisions with obstacles according to the Ukrainian Standard DSTU EN 15227. Service loads on the load-bearing components of swap-body freight cars were estimated, and recommendations were developed on fasteners that would provide safe transportation of various freights in swap-body cars. Based on the results of the studies, a number of design solutions were proposed for Ukrainian railway vehicle components. Their implementation will offer a sizeable economic benefit, increase the train speed and safety, improve the vehicle–track interaction, and facilitate the formation of an up-to-date home railway complex and its integration into the European railway networks.

Анализ применения гидравлических гасителей колебаний в конструкциях рессорного подвешивания подвижного состава железнодорожного транспорта

Purpose: consideration of the issue of the use of hydraulic vibration dampers in spring suspension of various types of railway rolling stock. The article provides an overview of the layout of hydraulic vibration dampers in the spring suspension of rolling stock, their advantages and disadvantages are given Methods: review and analysis of spring suspension designs of various types of traction and non-traction rolling stock in operation, as well as patented designs. Analysis of the arrangement schemes of hydraulic vibration dampers in the spring suspension of rolling stock. Results: the main reason for the use of hydraulic dampers in spring suspension is the inability of cylindrical springs to minimize the influence of oscillatory movements of rolling stock that occur during its movement. The necessity of using hydraulic vibration dampers in structures of various types of rolling stock is substantiated. The arrangement schemes of hydraulic vibration dampers are considered. Examples of the use of hydraulic dampers in spring suspension of various types of rolling stock are given. Practical significance: the necessity of using hydraulic vibration dampers is shown not only in the structures of the undercarriage of passenger cars and locomotives, but also in the spring suspension of freight cars. The use of hydraulic vibration dampers makes it possible to minimize the negative impact of oscillatory movements on both the structure of the rolling stock and the health of passengers and locomotive crews, as well as to increase the comfort of their stay. The use of hydraulic dampers in the spring suspension of freight rolling stock can increase the speed of its movement by improving the running qualities of freight cars and the degree of safety of transported goods.

PROBLEMS OF FREIGHT CAR FLOWS DISTRIBUTION ON RAILWAY NETWORKS

Purpose. The purpose of the article is a critical analysis of the existing methods of freight car flows distribution on the railway network and the determination of the directions of these methods adaptation to the operating conditions of the Ukrainian railway transport. Methodology. The research was carried out on the basis of the processing of literary sources in the scientometric databases Scopus and Google Scholar. Results. The distribution of car flows on the railway network is one of the stages of developing a plan for the trains formation. The methods of solving this problem, which are currently used in the practical work of railway transport, were developed during the time of the planned state economy. They are based on the solution of a single-criterion optimization problem aimed at finding such a distribution of car flows on the network that minimizes the cost of transportation for the railway. Reforming the railway transport market with the aim of introducing competition requires the complication of methods of solving the problem of distribution of car flows to take into account the conflicting goals of independent participants in the transport process. The conducted studies showed that the main method of modeling the structure of the railway transport network and the volumes of car flows in it is the theory of graphs; determination of the carrying capacity of elements of the railway network is carried out by the methods of the theory of railway operation, simulation modeling and correlation analysis; determination of the optimal distribution of bandwidth is carried out by comparing competing options, as well as by linear and non-linear programming methods, adaptive control methods using neural networks; the behavior of participants in the transportation process during the allocation of bandwidth is investigated by game theory methods. It has been established that in modern conditions, the task of determining the criterion of equal access to congested sections on the branched railway network and the task of distributing car flows on the network in conditions of fluctuating car flows during transportation by regular trains and trains to order require additional research. Originality. The scientific novelty of the work consists in the critical analysis and generalization of modern methods used to solve the problem of distribution freight car flows distribution on railway networks. Practical value. The practical significance of the results lies in determining the inconsistency of the methods that are practically used on the railways of Ukraine for the distribution of car flows, with the modern conditions of operation of railway transport. Scientific methods have been established that allow to improve approaches to solving the problem of rational distribution of car flows, taking into account the interests of various participants in the transportation process.

ON THE ISSUE OF ENSURING THE OPERABILITY OF FREIGHT CAR AXLE BOXES

The article is devoted to analysing the reliability of freight car axle boxes. Wheelsets and axle boxes are especially important for ensuring the traffic safety of trains. The study examined cases of cars uncoupling from a train along the route due to technical faults resulting in delays in train movement. The analysis covered the period of 1995–2023. It found that failures of car axle boxes and automatic brakes predominated. After a significant decrease from 2000–2014, the number of roller axle box failures in recent years fluctuated at 30% of the total number of uncouplings. The analysis obtained a dependency for the change in car detachments due to roller bearing failures, calculated per 1,000 cars in the operating fleet. Despite fluctuations in the number of railcars, the safety level of operations in recent years remained virtually at the same level. The study highlighted that excessive heating accompanies damage in the elements of the axle box unit. It considered methods for detecting possible failures and their advantages and disadvantages. The authors identified the primary causes of axle box component failures. Cylindrical bearings and end mountings remain the most dangerous for failure probability. We demonstrated that the axle box design with cylindrical bearings has a fundamental flaw. Axial forces are perceived through the rolling friction of the ends of the rollers against the ring flanges, leading to the formation of ‘chevron’ scratches and dents on the roller ends, which are stress concentrators. The study established that the surface of the axle box housing is constantly in contact with the side frame of the freight car bogie and wears out. It results in pinching of the axle box body and contributes to the appearance of additional permanent forces acting on the axle box assembly. The end-bearing mounts are weakened and destroyed. Skewed rollers in the bearings cause fatigue failure of the rolling races. It leads to increased heating of the axle box assemblies and uncoupling of the car. A promising direction is the improvement of axle box bodies. Keywords: rolling stock, traffic safety, reliability, axle box assembly, roller bearing, axle box body, failure.

Fault diagnosis of railway freight car rolling bearings based on ACMD and improved MCKD

To address the issue of accurately extracting fault characteristic information of railway freight car bearings under noisy conditions, this paper proposes a fault diagnosis method based on Adaptive Chirp Mode Decomposition (ACMD) and an optimized Maximum Correlation Kurtosis Deconvolution (MCKD) using a Sparrow Search Algorithm Combining Sine-Cosine and Cauchy Mutation (SCSSA). Firstly, ACMD is used to decompose and reconstruct the original fault signal to obtain several Intrinsic Mode Functions (IMFs). Then, the IMFs are filtered according to the Gini coefficient indicator, with the IMF having the largest Gini coefficient selected as the optimal component. Secondly, the SCSSA is employed to iteratively optimize the filter length L, fault signal period T, and displacement parameter M in the MCKD algorithm, determining the optimal parameter combination for MCKD. This avoids the limitations of manual settings and enhances the accuracy of fault diagnosis. The optimized MCKD is then applied to the optimal component, and deconvolution is performed using maximum correlation kurtosis as the criterion to extract fault characteristic information through its envelope spectrum. To verify the effectiveness and generalizability of the proposed method, simulations, experimental signals from the Case Western Reserve University Bearing Center, and actual measured signals from railway freight car bearing 353130B are used to analyze inner ring faults. The experimental results demonstrate that the method can accurately extract fault characteristic information of railway freight car bearings under noise interference and identify the fault type.

Dual-Model Derailment Detection Algorithm Based on Variational Bayesian Kalman Filtering.

A derailment detection algorithm for railway freight cars based on micro inertial measurement units was designed to address the complex issue of the disassembly and assembly of derailment braking devices. Firstly, a horizontal attitude measurement model for freight cars was established, and attitude measurement algorithms based on gyroscopes and accelerometers were introduced. Subsequently, a high-precision attitude measurement algorithm based on variational Bayesian Kalman filtering was proposed, which used acceleration information as the observation data to correct attitude errors. In order to improve the accuracy of derailment detection, a dual-model instantaneous attitude difference measurement technique was further proposed. In order to verify the effectiveness of the algorithm, offline data from simulation experiments and in-vehicle experiments were used to validate the proposed algorithm. The results showed that the proposed algorithm can effectively improve the measurement accuracy of horizontal attitude changes, reducing the error by 89% compared to pure inertial attitude calculation, laying a technical foundation for improving the accuracy of derailment detection.

Determining the influence of wheelset arrangement in the model 18-100 bogies on the level of steering efforts in the wheel-rail flange contacts

The object of this study is the process of directing the bogies of model 18-100 freight cars along a rail track, in particular, along curved sections of the track. The task to be solved was to determine the influence of wheelset arrangement on the level of steering forces in the flange contacts. A calculation diagram and a mathematical model of fitting the bogie into the curved section of the track have been built. The bogie loading scheme by external forces, including lateral rocking forces acting on the car in a curve, has been refined. In this case, the method of pseudo-statics of the mechanical system, which is a system of nonlinear algebraic equations, was applied. The calculation module Given-Find in the Mathcad software package (USA) was used to solve the mathematical model. It was established that the misalignment of wheelsets in the frames of model 18-100 bogies was of an accumulative nature. At the maximum operating angles of misalignment of wheelsets, the lateral steering forces in the flange contacts increase by 40–60 % compared to the rated setting. These angles can be up to 0.015 rad (0.85 degrees). The field of practical application of the results is railroad transportation, in particular, the system of maintenance and repair of freight cars on bogies of the 18-100 model. At the same time, the condition for the practical application of the research results is the expediency of introducing into the maintenance system the technological operation of controlling the deviation of wheelset arrangement in the bogie relative to the rated one. The current study will contribute to the construction of a measuring system for monitoring the deviation of wheelset arrangement in the bogie relative to the rated one. This proves the expediency of introducing into the trolley maintenance system the technological operation of controlling the deviation of wheelsets and designing a device for monitoring this parameter

Оценка влияния неровностей и модели рельсового пути на динамические качества грузового вагона

Objective: compare the requirements of documents RD 32.68-96 and PNST 511-2020 regarding the assignment of unevenness of rail threads during computer modeling of railway crews. To evaluate the influence of irregularities and the model of the rail track on the dynamic qualities of a freight car when moving along straight and curved sections. Methods: a review and analysis of various standards for calculated track irregularities (RD 32.68-96 and PNST 511-2020), as well as an assessment of the influence of the rail track model on dynamic qualities of a freight car, allowed to form the most representative calculation cases for modeling the movement of a railway carriage along a track of various designs (straight, curved sections) and conduct a study of the dynamics of a freight car in a specialized environment the Universal Mechanism software package. Results: a comparison of different regulatory documents used in the Russian Federation and the current standards for calculated track irregularities has been carried out. Computer modeling methods have been used to obtain histograms of various indicators for a universal gondola car mounted on bogies of model 18-100 when moving along a path of various designs. Practical importance: the obtained results of the work can later be used to develop the theoretical foundations of the national standard on railway track irregularities for modeling the movement of rolling stock.

Increasing the Fuel Efficiency of a Mainline Diesel Locomotive with Separate Section Loading

Purpose. The paper aims to investigate the increase of fuel efficiency of a mainline freight locomotive in the case of separate loading of diesel generators of its individual sections. Methodology. The study was carried out for the non-electrified section between Kharkiv-Sorting and Sumy stations during the movement of a freight train with 45 loaded and empty freight cars in both directions. The movement of a train with a freight mainline two-section diesel locomotive 2TE116 was taken. To determine the parameters of the movement, a mathematical model was developed, which was used to solve a series of traction problems. The traction problems are calculated for the cases of train movement with a series diesel locomotive and a diesel locomotive with separate loading of diesel generators of its individual sections. A method of loading sections is proposed for modeling and the traction characteristics of the locomotive are constructed in accordance with this method. Findings. It has been established that the use of separate loading of diesel generators of individual sections of a diesel locomotive when running a train with loaded cars reduces fuel consumption by 18.7...19.6 % compared to running a serial diesel locomotive. For the case of a train with empty cars, the reduction in fuel consumption is 8.1...10.3 % compared to a train with a serial diesel locomotive. It has been found that the movement of a train with empty cars can be carried out with traction by one section of a diesel locomotive. In this case, the reduction in fuel consumption is 29.5...31.0 %. In all the studied cases, the duration of the movement is practically the same. Originality. The authors of this paper have solved traction problems for a real track section when a train with a freight diesel locomotive is moving, where separate loading of diesel generators of its sections is used. A method for forming the traction characteristics of a locomotive with separate loading of diesel generators is proposed. Practical value. The developed mathematical models of train movement, including for the case of separate loading of diesel generators of diesel locomotive sections, can be used in the modernization of diesel locomotives or the creation of diesel rolling stock using a multi-diesel power plant.

Ways of improving of freight car design

Ways of improving of freight car design

ОБОСНОВАНИЕ КОНСТРУКЦИИ КРЫТОГО ГРУЗОВОГО ВАГОНА С УВЕЛИЧЕННЫМ ОБЪЕМОМ ГРУЗОВОГО ПОМЕЩЕНИЯ

The market of covered freight cars, as well as existing designs of this car type of domestic and foreign production is analyzed. Promising trends of making innovative designs of freight cars for the transportation of piece and container goods are found out. The original design of a covered freight car with an increased body space due to the use of the space between trucks is proposed. To reduce the complexity of loading and unloading operations, sliding sections of the side walls and roof are provided in the car design. To confirm the compliance of the proposed design with the requirements of regulatory and technical documents, the car was entered into the dimension, checking for automatic coupling at the junction of a straight line and a curve, passage in the coupling of an s-shaped curve and coupling of a straight line and a curve, and a single car along a circular curve of a small radius, as well as passing without self-decoupling of the hump of the sorting slide, the ramp exit of the train ferry. A safety assessment is carried out with regard to rolling the wheel onto the rail and overturning the car in curves. The car dynamic characteristics are found out by mathematical modeling methods. The assessment of the strength of the body load-bearing structure, lifting mechanisms of the floor sections, sliding sections of the roof and side walls is performed using the finite element method implemented in the environment of a specialized software package. The results obtained as a result of calculations and computer modeling confirmed the operability and safety of the proposed design of a covered freight car with an increased loading space.

The Nonlinear Lateral Stability of a Four-Axle Freight Car with Y25 Bogies and Measures to Improve Its Faults

The Nonlinear Lateral Stability of a Four-Axle Freight Car with Y25 Bogies and Measures to Improve Its Faults

ПРОБЛЕМЫ И МЕТОДЫ СОВЕРШЕНСТВОВАНИЯ АВТОСЦЕПНОГО УСТРОЙСТВА ГРУЗОВЫХ ВАГОНОВ С УЧЕТОМ ОСОБЕННОСТЕЙ ЭКСПЛУАТАЦИИ

The problems to operate the automatic coupling device are considered, taking into account significant changes in the operating conditions of freight cars. The operation experience of freight car automatic coupling devices of domestic railways and the United States of America is analyzed; common problematic issues are identified. Approaches to the study of modes of longitudinal-dynamic impact of cars are defined, a simplified model is given. There is a need to change the design of the automatic coupling device of freight cars by using two sequentially arranged blocks with working elements, as well as improving the properties of the working material of absorbing devices, especially in operating conditions over a wide temperature range.

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ ПРОСТОРОВИХ КОЛИВАНЬ РУХОМОГО СКЛАДУ ЗАЛІЗНИЦЬ

The development of railway transport is accompanied by the introduction of innovative equipment and modern information technologies. The creation of railway rolling stock and rail machinery requires an assessment of their strength and dynamic qualities even at the stage of design and experimental production, therefore, the development of specialized software for evaluating the main parameters of the rolling stock structures being created is an urgent scientific and applied problem for railway transport and transport engineering. Theoretical studies of spatial fluctuations of certain types of railway rolling stock were performed and recommendations were obtained for the formation of parameters of the structures of freight cars and special rolling stock. When conducting theoretical research, the author's DYNRAIL-PRO software complex was used, which was verified and the reliability of the calculation results was proven.

Multi-objective optimization of electro-pneumatic braking process with fuzzy logic control for heavy haul railway applications

ABSTRACT This paper presents a novel approach to multi-objective optimization in heavy haul trains’ electro-pneumatic braking systems using optimizable fuzzy control. Initial findings indicate that a straightforward replacement of pneumatically controlled valves with electro-pneumatic ones, without significant control schedule modifications, fails to substantially improve the dynamics behaviour of rolling-stock. Consequently, a more sophisticated strategy based on optimizable fuzzy logic control for the electro-pneumatic valves was developed. This approach utilizes multi-objective optimization to simultaneously minimize energy dissipation during braking and reduce force peaks in freight car draft gears. The optimal solution achieved demonstrates a 13.41% reduction in kinetic energy dissipation during downhill sections, along with a concurrent decrease in draft gear peak forces by 14.22% in traction and 3.16% in buff regimes compared to standard rolling-stock with pneumatically controlled valves. This optimized fuzzy braking controller outperforms standard procedures, highlighting its potential to enhance heavy haul train efficiency while adhering to safety standards.

Исследование ударной вязкости стали литых несущих деталей грузовых вагонов

Objective: to conduct comprehensive experimental studies of the impact toughness of 20GL cast steel, which is used for the manufacture of load-bearing parts of freight cars. To obtain a serial diagram of the dependence of the impact toughness value on the test temperature. Methods: the method of mechanical testing of cast steel specimens under impact loading was used, which allows obtaining quantitative estimates of the material’s ability to resist impact fracture at different temperatures (impact toughness tests). Micrographic analysis of the fracture surface was used to study the surface of impact fracture. Results: based on the results of tests of specimens made of 20GL cast steel, experimental dependences P = f (τ); E = f (τ) and a serial diagram (KCV — T) were constructed, which allow evaluating the performance of cast steel in the manufacture of load-bearing parts of cars for various climatic conditions of operation. Practical significance: the results obtained allow us to carry out work to improve the technological and service properties of cast load-bearing parts of freight cars.

Методика определения потерь участковой скорости движения грузовых поездов в границах железной дороги

Purpose: to develop a methodology for estimating the total losses of the local speed of freight trains, which, unlike existing methods based on calculating losses caused by the influence of individual operational factors, will be based on the use of statistical data, and take into account the entire range of operational factors that influence the implementation of the indicator under consideration. Methods: formation of a statistical database of railway operational parameters and conducting research on its basis using the tools of probability theory and mathematical statistics: assessing the distribution of the quantities under consideration, correlation and regression analysis. Results: it was established that 75 % of the variability in the local speed of freight trains is explained by changes in the size of the operating fleet of freight cars. Based on this, a methodology has been developed for estimating losses in the local speed of freight trains through the size of the working fleet of freight cars on the railway. A graphical and analytical method for determining these losses is proposed. Practical significance: it is shown that the developed methodology, in contrast to existing ones, makes it possible to more accurately estimate the loss of local speed of freight trains. Its use makes it possible to plan and analyze the implementation of the local speed of freight trains, taking into account the evolving operational work on the railway.

Simulation of spring-friction set of freight car truck, taking into account track profile

The purpose of this article is the mathematical modeling of a spring-friction set of a freight car trolley depending on the profile of the railway track. The article uses the methodology of the results of the generalized model of power interaction of friction pairs "pressure beam-friction wedge" and "friction wedge-friction bar" of the spring-friction set of the cart 18-578 in the mechanical system "track-car-load," in a particular case cart from which such models of the e of the freight car 18-100 can be obtained. The manuscript contains a software study using a computer simulation of a freight wagon trolley, which complements the experimental studies. The mathematical (symbolic) method in the computer algebra system MathCAD (a type of computer-aided design system) is used to solve the equations of equilibrium of the supercharger beam as a real object. In the course of the experimental study, a computational mathematical model of the force action of friction pairs of spring-absorbing trolley apparatuses was developed, and the results of calculations of the reaction of the friction bar to the friction wedge were mathematically obtained. The optimal parameters were obtained analytically, and the indicators of the angles of inclination of the contact surfaces of the trolley of the freight car were justified.

Development of an Operational Digital Twin of a Freight Car Braking System for Fault Diagnosis

AbstractIn the evolving landscape of digital technology, the concept of digital twinning has emerged as one of the most important innovations. Digital twinning, characterized by a one‐to‐one correlation with physical structures in a digital environment, has become an important tool in transferring physical dynamics into digital replicas. This platform, integrating advanced sensor technologies and analytical tools, enables a comprehensive monitoring, diagnosis, and optimization concept. The present research focuses on the application of digital twinning in addressing the complex challenge of managing fault types in freight car brakes. A Digital Twin (DT) model of a freight car braking system is developed that forms the basis for an innovative approach to fault classification. This approach leverages the ability of the DT to emulate and analyze the behavior of the braking system under different conditions. The effectiveness of the proposed method is evaluated through extensive testing and analysis with an experimental data set. The results show that the method is able to accurately diagnose different types of faults. This represents a significant advance in the field of freight car brake system diagnosis.