Railway Cars Research Articles

Bamboo-Inspired Renewable, Lightweight, and Vibration-Damping Laminated Structural Materials for the Floor of a Railroad Car.

It is important for the floor of railroad cars to be fitted with vibration- and noise-reducing, fire-resistant, and durable materials. In this study, inspired by a delicate and ordered bamboo gradient structure and excellent multilevel interfaces, we fabricated a laminated composite with characteristics similar to those of the bamboo structure using a simple and effective "top-down" method by laminating fast-growing wood, waste rubber, and bamboo charcoal plastic sheets made of bamboo processing residues. This composite material combines the unique advantages of a laminated structure design and composite interface bionics. The low density (0.73 g/cm3) of the laminated composite results in a specific modulus of 13.03 GPa cm3/g, a vibration damping ratio of 6.61%, and an impact toughness of 14.16 J/cm2, which is significantly higher than that of other wood-based composites used for high-speed rail floors, such as Birch plywood (BP). In addition, we also investigated the laminated composite bonding property, fire resistance, and fatigue performance. This biomimetic bamboo-wood composite material has great potential for application in fitting the floor of eco-friendly railway cars.

Aïda Muluneh's Homebound: A Journey in Photography & Addis Foto Fest: Nine Years Survey

Aïda Muluneh's Homebound: A Journey in Photography & Addis Foto Fest: Nine Years Survey

Key Technologies of Physical and Virtual Test Rig for Railway Freight Car body

On the one hand, considering that the traditional fatigue method of railway freight cars is based on damage as a parameter, the influence of stress waveform cannot be considered. On the other hand, physical experiments have the characteristics of lag, long period, and high cost. The full-scale physical test and virtual test of car body are carried out. First of all, the data processing method of small deletion and the inverse problem load acquisition method based on data to data are proposed. Secondly, the dynamic stress calculation method with the bench as the boundary is proposed. Finally, taking the obtained load as the input of the physical and virtual bench, a new fatigue test method for simulating the running attitude of the car body line is completed. The acceleration RMS error of the C70E gondola body is less than 6%, the stress RMS is less than 13%, and the equivalent mileage is 3.125 million highway test results show that the car meets the life requirements of the car body. The inverse problem analysis results of virtual and physical tests are basically consistent, and the study of this method provides a basis for improving the fatigue reliability of freight car bodies.

Variable Incremental Controller of Permanent-Magnet Synchronous Motor for Voltage-Based Flux-Weakening Control

This study presents a variable incremental controller for flux-weakening control in the high-speed operation area of a permanent-magnetic synchronous motor (PMSM). In general, voltage-based flux-weakening control utilizes a reference voltage and a PI controller to generate a flux component current. In this paper, the voltage-based flux-weakening control is performed using the variable incremental controller instead of the PI controller. The variable incremental controller can control the flux component current using only the maximum speed and maximum current of the motor. A method for properly setting an appropriate variable incremental controller using acceleration is additionally presented. A variable incremental controller is applied and, accordingly, the overshoot of the motor speed can be reduced and the speed error of the motor can be minimized by reducing the difference between the actual motor and targeted accelerations. This method can simplify the design of a controller that utilizes flux-weakening control and can be applied to railroad cars whose acceleration does not alter frequently to increase the effect of motor control.

Suspension Control and Characterization of a Variable Damping Magneto-Rheological Mount for a Micro Autonomous Railway Inspection Car

This paper aims to present a suspension control strategy for a semi-active mount with variable damping utilizing a smart magneto-rheological fluid (MRF), which will be applied in a micro autonomous railway inspection car as a primary suspension to protect the inspection equipment from the large suspension vibration on rails. We proposed a new multi-pole structure design for a semi-active magneto-rheological mount (MR mount) that can provide both a high damping force and a wide damping force band. Firstly, the mathematical model of MR mount dynamics was derived; secondly, a skyhook control strategy was developed for the MR mount; and finally, a dynamic simulation problem using Matlab software was constructed to evaluate the performance of the MR mount. The dynamic simulation results showed that the proposed MR mount using a skyhook control strategy showed greater vibration isolation performance compared to conventional passive mounts. In particular, the absolute displacement, velocity, and acceleration of the detector device were reduced by 83.33%, 77%, and 70%, respectively. The suspension vibration transmitted to the inspection device also decreased significantly, compared to input oscillation (i.e., un-sprung mass oscillation). Specifically, the suspension vibration reduced by a half at the excitation frequency of 2-fold the natural frequency and by greater magnitudes at higher excitation frequencies.

Reliability Assessment Model and Simulation of Journal Bearing of Railway Freight Cars Based on Bayesian Method under Small Sample Sizes

Generally, the box bearing of railway freight cars has no bearing sample failure data at the end of the time-terminated reliability test. However, it is expensive and has high service reliability requirements. Given a small sample size and zero-failure data, the traditional failure probability calculation formula based on a large sample size and the reliability modeling technique cannot easily assess the reliability of rolling bearings accurately. Considering the applicability of the bearing of railway freight cars, this study integrated the prior information of samples and the simulation test information according to Bayes statistical theory, deduced the mathematical model of cumulative failure probability under failure-free data, calculated the distribution parameters using the least square method, and established the reliability estimation model of rolling bearings on the basis of Weibull distribution. The failure-free simulation data of rolling bearings were produced according to the Monte Carlo simulation, and the reliability of the journal bearing of railway freight cars was simulated and assessed by three methods. Simulation results demonstrate that the proposed reliable Bayes multilayer estimation method could not only meet the design requirements of the ISO 281 rolling bearing standards on that basis of the failure-free data and small sample size of the time-terminated simulation, but also assess the reliability of the rolling bearing of railway freight cars.

Determining the features of loading the bearing structure of a multifunctional car under operating modes

This paper substantiates the modernization and commissioning of a railroad car for high-temperature, bulk/loose cargoes in order to improve the efficiency of railroad transportation. A feature of the car is the presence of an open-type boiler, which is made of heat-resistant material. To prevent splashing of transported cargo, it is possible to use a removable cover, which is attached to the top of the boiler. The boiler of the car was calculated for strength under the main operating modes. The vertical load on the boiler was taken into consideration while accounting for the transportation of bulk cargo, as well as longitudinal, and the effect of temperature load. The strength was calculated by the method of finite elements. It is taken into consideration that the boiler is made of composite heat-resistant material. The calculation results showed that with the considered load modes, the strength of the boiler is ensured. The dynamic load of the boiler was mathematically modeled at car shunting. The calculation was performed in a flat coordinate system. Solving the mathematical model of the car dynamic load has established that the maximum acceleration that acts on the boiler is 36.5 m/s2. The dynamic load of the boiler was simulated. The dislocation fields and numerical values of accelerations that act on it were determined. The maximum acceleration, in this case, is concentrated in the bottom of the boiler; it is 37.4 m/s2. To verify the dynamic load model, the F-criterion was used for calculation. It has been established that the hypothesis about the adequacy of the model is confirmed. The study reported here could contribute to improving the efficiency of railroad transport operation and advancing the design of multifunctional car structures.

APPROACHES AND PROSPECTS OF IMPROVEMENT OF DUMP CARS FOR OPERATION ON 1520-mm MAINLINE RAILWAYS

The article deals with the models of dump cars, which form the major part of the mainline railway car fleet of 1520 mm. The technical characteristics of the most common mainline dump cars models are given. The design features of the dump car model 31-638, designed for transportation and mechanized unloading of bulk and lump cargo, are presented. Modern models of dump cars of domestic and foreign production for the main railway transport of 1520 mm track, which were constricted and put into serial production in recent years, are presented. The results of comparative analysis of technical characteristics of dump cars of the last generation to modern models of dump cars showed that one of the main advantages of the latter is reduction of container weight, increase of load capacity and body volume, improving of strength and reliability of separate units and systems. The problem units and systems of the existing models of main-line dump cars are determined based on the results of their operation, which need further strengthening. The focus areas of improving the design of modern models of dump cars for the 1520 mm main railway vehicles are defined. The technical requirements for the next generation dump cars, which are planned to be constructed and put into serial production in the coming years for operation on the mainline railway tracks, are proposed. The technical requirements are formed taking into account the research results of modern mainline dump cars design, review of technical and design documentation for these railway vehicles, as well as analysis of requirements and wishes of customers. The necessity of carrying out relevant research and engineering works on the development of new generation dump cars for the main railway transport is substantiated. The content of the article will contribute to the construction of new models of dump cars for the main railway transport and significant upgrading of existing models, as well as increase the efficiency of their operation.

Conceptual model of railway car traffic organisation based on the end-to-end control of freight delivery times

Introduction. The article presents the analysis of non-compliance of delivery times of railway cargoes with the regulatory time frames. The analysis reveals a decrease in the reliability of delivery, one of the most important quality indicators. The authors assess the operation of existing automated control systems, which shows discontinuities and non-automated functions in the framework of the end-to-end control of the goods and empty cars delivery times. The purpose of the ar tic le is to propose and justify the use of a conceptual model for organising car traffic, based on end-to-end control of delivery times and risk-oriented impact on the limiting technological elements.Materials and methods. The authors applied the methods of the modern theory of traffic management, the theory of mathematical statistics and the theory of decision making.Results. The authors propose a conceptual model based on end-to-end control of goods delivery times and a risk-oriented impact on the limiting technological elements as a part of development of end-to-end process of the goods and empty cars delivery. The model highlights the following key provisions: control of the actual delivery time to stations by assessing the compliance with the technological standard operation times; end-to-end risk-oriented control of actual delivery times of cargo and empty cars along the entire route; providing recommendations to accelerate the advancement of the car traffic based on the technical and economic feasibility study.Discussion and conclusion. The implementation of the proposed conceptual model enables to employ scientifically based operational decision-making to control the flow of the traffic at each stage along the route and to improve the quality of transport services and the quality of operational work of railway transport. The conceptual model can be implemented as a separate module integrated into the existing automated station control system.

Reduction of dimension in the problem of optimal management of a freight cars fleet using unmanned locomotives

This paper considers the problem of optimal management of a fleet of freight cars by a transport railway operator. The solution to this problem is an optimal plan, which is a timetable for the movement of freight and empty railway cars, following which the transport operator will receive the maximum profit for the estimated period of time. This problem is reduced to the problem of linear programming of large dimension. Unlike the works of other authors on this topic, which mainly deal with methods of numerical solution of the corresponding linear programming problems, this article focuses on an algorithm that allows one to reduce their dimensionality. This can be achieved by excluding from the calculation those routes that obviously cannot be involved in the solution, or whose probability of participation in the final solution is estimated as extremely low. The effectiveness of the proposed modified algorithm was confirmed both on a model example (several stations, a short planning horizon) and on a real example (more than 1.000 stations, a long planning horizon). In the first case, there was a decrease in the dimension of the problem by 44%, while in the second – by 30 times.

New methods for dynamically substructured system testing of a railway car pantograph

This study proposes new pantograph testing methods for railway pantograph/overhead catenary systems (OCS), based upon substructured testing consisting of a physical pantograph and a numerical OCS model. Hence, this work builds upon a previously presented work, (using the dynamically substructured system approach developed by Stoten and Hyde), which was conducted on a relatively simple mechanical structure in the Automatic Control and Test Laboratory (ACTLab), University of Bristol, UK. In this current paper, the dynamically substructured system (DSS) testing method is applied to a real shinkansen pantograph, using various actuator/DSS configurations that have been implemented at the Railway Technical Research Institute, Tokyo, Japan. In the first of these tests, a conventional servohydraulic actuated rig is used to represent phenomena due to the dropper-passing frequency. Resulting DSS test data are compared with those generated by a numerical simulation of the emulated system, i.e. the system to be represented by the DSS experimentation. Then, in the second set of investigations, the DSS method is used in conjunction with a new ‘rotational disc’ test rig that is arranged to be in dynamic interaction with the shinkansen pantograph contact head. This novel experimental system enables the investigation of dynamic interactions between the overhead catenary system contact wire and the pantograph head, due to span-passing. Again, results from this experimental investigation are compared with those generated by a purely numerical simulation of the emulated system.

Modal vibration decomposition method and its application on multi-mode vibration control of high-speed railway car bodies

The vibration of a railway car body is a superposition of the vibrations of its various modes. It is typically easy to obtain the physical vibration of the car body using sensors in an in situ or a simulated test vehicle. However, it is difficult to determine the modal vibration of the body and its contribution. There are no effective multi-mode vibration control methods for the car bodies. This study proposes a modal vibration decomposition method (MVDM) based on singular value decomposition (SVD) and least squares fitting (LSF). Accordingly, the physical vibration of a railway car body is decomposed into modal vibrations. A method for calculating the modal contribution factor (MCF) is presented, and the dominant flexible modes of the car body are determined and considered the target for the vibration control method. Several pieces of equipment are considered as dynamic vibration absorbers (DVAs) to control the multi-mode vibration of the car body using the dynamic vibration absorption theory and determine the installation parameters of the individual equipment. Finally, the effectiveness of vibration control is verified through dynamic simulations. The results demonstrate the effective decomposition of the physical vibration of the car body into various modal vibrations using the MVDM. This provides accurate data for the MCF calculation and determination of the flexible modes of the car body. The proposed method reduces the vibration of the target modes and improves the ride quality of the railway vehicle. At the optimal damping ratio, the vibration of the DVA-based equipment itself is acceptable. This allows for multi-mode vibration control without requiring extensive modification to the car body structure or suspension system parameters of the vehicle.

ОБ ОЦЕНКАХ РАБОЧИХ КАЧЕСТВ ПОГЛОЩАЮЩИХ АППАРАТОВ АВТОСЦЕПНОГО ОБОРУДОВАНИЯ ПОДВИЖНОГО СОСТАВА ЖЕЛЕЗНЫХ ДОРОГ

The study objective is to develop methods for performance evaluation of center coupler draft gears in various operating conditions. The problem to which the paper is devoted is to reduce the dynamic loading of the rolling stock by means of using efficient draft gears. The research methods on which this study is based are widely used in the dynamics of railroad cars. Typical modes of shunting impact of cars are considered, which are characterized by the highest level of forces in automatic couplings. The design schemes of impacts are considered as a system of connected material points. On the basis of D'Alembert's principle, differential equations of motion are made, and they are integrated by the Euler method. The novelty of the work is in developing an approach to evaluate the performance of draft gears using the proposed integrated evaluation. The results of the study are the nomographs of the effort in the draft gear, depending on car weight and the speed of impact. The conclusions of the study contain the evaluation of the results of applying the proposed approach, as well as recommendations on possible use of the proposed approaches.

A study of wheel wear on a high-speed railway motor car

Wheel/rail wear is one of the key issues in the safe operation of a high-speed railway motor car. This paper analyzes and predicts the wheel wear evolution of motor car during the long-term operation process. Firstly, the detailed motor car with gear transmission systems and trailer car of the high-speed train, which take into account various non-linear factors such as dampers, bump stops, wheel/rail contact relation, etc., are developed to obtain interaction force between wheel and rail. Secondly, according to the tread update strategy based on fixed travel distance, a novel wheel wear prediction model integrating the Archard wear model and previous dynamics system is established. In order to more accurately obtain the dynamic responses of the motor car, the comprehensive gear transmission system coupling with motor bogie is also built, which considers the time-varying mesh stiffness and gear shift coefficient. And the corresponding traction characteristic curve is also applied to the gear transmission system. Finally, the wheel wear evolution in one re-profiling cycle is simulated to verify the developed model, and the wheel wear mechanism is investigated in detail. Furthermore, the influence of traction velocity on wheel wear is also investigated. The simulation shows that the cumulative wear amount of both two cars increases gradually and the wear rate decreases gradually with traveling mileage, but the wear rate of the trailer car decreases faster than that of the motor car due to larger longitudinal creepage and longitudinal creep force induced by traction torque. Moreover, the max wheel wear depth and wear bandwidth for motor car gradually increase with traction velocity. While the discrepancies of the max wheel wear depth and wear bandwidth for trailer car are small under different speeds.

Driving Utah's Rivers: Working Water in the West

Driving Utah's Rivers: Working Water in the West

Making an American Opera Career: Conductor May Valentine (1890–1974) and a Woman's Role(s) in the Business of Opera

Making an American Opera Career: Conductor May Valentine (1890–1974) and a Woman's Role(s) in the Business of Opera

Multiple load recognition and fatigue assessment on longitudinal stop of railway freight car

AbstractSafety evaluation of key support components remains a challenge for freight trains because of the difficulties in direct and precise monitoring. In this work, the longitudinal stop on well-hole freight train, which prevents the cargo from sliding in anterior-posterior direction, is investigated. Load identification approach is proposed via strain perception at multiple locations, which are selected from the optimal positions sensitive to longitudinal and lateral loading in Finite Element Analysis (FEA). Validation is performed in random loading simulations. The identified loads deviate from the random sets within 4.07%. Longitudinal and lateral forces are recognized in an attempt to calculate the signed von Mises (SVM) stress of the longitudinal stop structure for fatigue evaluation. In application, the reconstructed structural stress climbs up to 107.1 MPa for the right weld base. Employing the rain-flow counting and Miner’s damage rule, the recommendation for load spectra grade in convergence is 64 groups. The equivalent fatigue damage is 0.854 and it drops to 30% in the statistical annual maximum mileage equivalency. Research outcome reveals that the proposed method enables the real-time monitoring of service loads and structural stress in railway freight transport, which provides scientific evidence for its maintenance planning and structural optimization.

Investigating thermal environment inside the kitchen of air‐conditioned pantry car on Indian Railway using CFD

AbstractIn an indoor kitchen environment, proper installation of supplying air system is essential for maintaining optimal human thermal comfort level. Current thermal comfort investigation has been accomplished during “various cooking periods (breakfast, lunch, snacks, dinner)” inside the air‐conditioned kitchen environment of railway pantry car in India. The study goals to improve thermal comfort inside the pantry kitchen by implementing proper installation of the supply air system. A field experiment and computational fluid dynamics approach has been carried out during the summer season. Also, standard effective temperature (SET) index was utilized to determine the thermal comfort status. Three proposed design modified cases of pantry cars (based on supplying air system concepts) have been executed followed by validation and comparison with the existing case model. Results revealed modified Case III as a better design concept (indicating better air supply circulation and temperature decrease at the desired location) compared to the existing and other two proposed cases. Simultaneously, the SET index range was 26.5–28.6°C; indicating “comfortable thermal sensation throughout the cooking period.” This study's outcomes suggest improvements in thermal comfort and energy savings of “air‐conditioned” pantry car kitchens in “Indian Railways” that could be referred directly.

Feasibility study for using the fillers in the bearing structure components of a gondola car

Purpose. To study the feasibility of using the fillers for the gondola car bearing structure components. This makes it possible to reduce both damage to the gondola car bearing structure components during operating modes of loading and the cost of unscheduled repairs. In addition, it can improve the efficiency of railway transport operation. Methodology. In order to substantiate the use of aluminium foam as a filler for the gondola car bearing structure components with a closed box-section, a computational modeling of loading under the most unfavorable operating mode, such as shunting collision, has been performed. Gondola car 12-757 model built at PJSC Kryukovsky Railway Car Building Works is chosen as a prototype. The calculation is performed using the finite element method implemented in the SolidWorks Simulation (CosmosWorks) software package. The fatigue strength and natural vibration frequencies of the gondola car bearing structure with a filler of its components have been calculated. The natural vibration frequencies of the bearing structure of the gondola car are calculated. The design service life of the gondola car bearing structure has been determined. The main indicators of the gondola car bearing structure dynamics have been studied. The calculation is made in a plane coordinate system. In this case, the mathematical model is solved by the Runge-Kutta method. Findings. The results of the conducted research have revealed that the use of aluminium foam as a filler for the gondola car bearing structure components contributes to reduction of their load-bearing capacity from 12 to 47% compared to the prototype wagon. Originality. The expediency of using aluminium foam as a filler of the gondola car bearing structure components by modeling its load-bearing capacity under the most unfavorable operating conditions has been scientifically substantiated. Practical value. By reducing the loading on the gondola car bearing structure, using aluminium foam as filler for its components, it is possible to increase fatigue strength, reduce the amount of damages, and, consequently, the cost of unscheduled repairs of the wagon. The conducted research can contribute to the creation of recommendations for developing the innovative rolling stock designs with improved technical-and-economic, as well as operational performance.

Class Rooms

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