Hasil untuk "Railroad engineering and operation"

ZHANG Xuhao, TONG Runfang, WANG Mengqian et al.

Bearing faults are a typical failure mode in motors. Traditional diagnostic methods based on vibration signals face high costs and strong noise interference, while current signal-based methods struggle to extract fault features due to dominant fundamental components. To address these issues, this paper proposes an intelligent diagnostic method. This method suppresses interference from fundamental current components and main harmonics through a time-shift cancellation technique, converts preprocessed one-dimensional signals into two-dimensional time-frequency feature maps using the smoothed pseudo Wigner-Ville distribution (SPWVD), performs cropping and stitching on these maps according to bearing fault characteristic frequencies, and finally the object detection model is built based on YOLO11 for automatic fault positioning and classification. Experimental results demonstrate that this method achieves up to 99.54% diagnostic accuracy under steady-state operating conditions, and can effectively extracts features from low-sampling-frequency current signals, significantly reducing hardware costs. Compared with traditional vibration signal methods, it exhibits stronger noise resistance and lower hardware dependence. Additionally, the three-stage diagnosis framework, consisting of signal preprocessing, time-frequency feature extraction, and intelligent classification, offers a low-cost and high-reliability solution for effective fault diagnosis of motor bearings.

WU Weiwei, DING Hao, HE Guanqiang et al.

To study the simulation effect of rail plate harmonic displacement excitation on wheel high-order wheel polygon geometric excitation, a wheel-plate rolling contact finite element model was developed based on simulation analysis software for the bogie high-frequency excitation test bench. The wheel-plate rolling vibration behaviors under 20^th-order polygon excitation with a wave depth of 0.05 mm were investigated through a solving process at a speed of 440 km/h. A comparative analysis was then conducted in both the time domain and frequency domain to identify similarities and differences between the two excitation modes. The simulation results for a 20^th-order polygon with a wave depth of 0.05 mm, under an axle weight of 17 t and a speed of 440 km/h, show that the maximum time-domain wheel-plate vertical force differed by only 1.5% between displacement excitation and geometric excitation. The spectral peak of wheel-plate vertical forces and the power spectral density (PSD) peak of axle box accelerations at the polygon excitation frequency of 840 Hz under displacement excitation are in good agreement with those under geometric excitation. The constant local curvature radius at the wheel-plate contact point under displacement excitation results in a larger contact spot area and a corresponding 21.7% reduction in contact stress. The amplitude of the wheel-plate vertical force spectrum and the power spectrum density of axle box accelerations increase with higher rail plate displacement amplitudes, while the peak frequency is basically unchanged. In summary, wheel polygon can be effectively simulated using displacement excitation as an alternative to geometric excitation on the bogie high-frequency excitation test bench.

C. Radhika, D. Hanirex

Predicting the traffic in the railroad is the secret to successful operation of the railroad and contented passengers. RNN-based real-time predictive model. The model training was in the form of real-time tracking data, weather reports, past train schedules, and maintenance records. The model was evaluated based on such metrics as MAE, RMSE, and R2. These promising values are the MAE of 2.3 minutes and RMSE of 3.1 minutes of the testing set, which indicates the model is correct in predicting the traffic situation. Moreover, the explanatory power of the model is enormous, with a value of R2 of 0.89. The flexibility is also seen in the fact that the model can always work in many different environments, including in bad weather or even when there is a need to carry out some repairs. According to the comparative analysis, there is evident improvement that leads to the better performance of the proposed work with an MAE of 2.3 minutes, RMSE of 3.1 minutes, and an R2 of 0.92. The results obtained demonstrate the quality of an RNN-based solution to improve the predictive railroad traffic forecasting in real time to obtain valuable information that can help to improve the operation of railways and to guarantee the satisfaction of passengers.

Guangyue Qi, Hongcheng Ding, Yu Zhang et al.

This study centers on the impact of water level fluctuations in water transfer tunnels regarding the mechanical response characteristics of railroad tunnels. Via a meticulously designed model test, the variation pattern of tunnel lining strain under diverse water level circumstances is thoroughly examined, furnishing a crucial foundation for the design, construction, and safe operation of tunnel engineering. The outcomes denote that water level alterations remarkably influence the tunnel's mechanical response. Each parameter exhibits disparate trends with the ascending water level, and discrepancies exist in the response features of different cross-sectional locations. The test results are as follows: (1) When the water level in the water transfer tunnel is 1 cm, the compressive strain at the outer elevated arch of section I reaches the maximum, and the compressive strain at the inner left arch foot is also the largest. (2) The tensile strain at the outer right arch waist of section II is the greatest, and the compression at the inner right arch waist is severe; the tensile strain at the outer right arch foot of section II exceeds the compressive strain at the arch top, and the compressive strain at the inner right arch foot is the largest. These findings offer a scientific underpinning for exploring the effect of water level loading on the mechanical response of the tunnel structure within the tunnel section beneath the water transfer tunnel, which is highly significant for enhancing project quality and ensuring operational safety.

LAN Weiyin, CUI Wei, CHEN Wenxuan et al.

The precise junction temperature monitoring is of paramount importance for enhancing the reliability of insulated gate bipolar transistor (IGBT) modules and extending the lifespan of devices. This paper introduces a method for monitoring junction temperature of IGBT modules based on turn-off voltages (TOV), which highlights resistance to load currents. The study initially verified the rationality of using TOVs as a temperature-sensitive electrical parameter. The deep neural network (DNN) technology was subsequently employed to eradicate the dependence of TOVs on load currents, facilitating accurate junction temperature prediction under varying operational conditions. The proposed method was validated through a single-phase pulse width modulation (PWM) experiment. The findings reveal an error range of ±5 ℃ for this method, demonstrating the feasibility of optimizing junction temperature monitoring through DNN utilization.

Sri Viknesh Permalu, Karthigesu Nagarajoo

Purpose – In an increasingly interconnected world, transportation infrastructure has emerged as a critical determinant of economic growth and global competitiveness. High-speed rail (HSR), characterized by its exceptional speed and efficiency, has garnered widespread attention as a transformative mode of transportation that transcends borders and fosters economic development. The Kuala Lumpur – Singapore (KL-SG) HSR project stands as a prominent exemplar of this paradigm, symbolizing the potential of HSR to serve as a catalyst for national economic advancement. Design/methodology/approach – This paper is prepared to provide an insight into the benefits and advantages of HSR based on proven case studies and references from global HSRs, including China, Spain, France and Japan. Findings – The findings that have been obtained focus on enhanced connectivity and accessibility, attracting foreign direct investment, revitalizing regional economies, urban development and city regeneration, boosting tourism and cultural exchange, human capital development, regional integration and environmental and sustainability benefits. Originality/value – The KL-SG HSR, linking Kuala Lumpur and Singapore, epitomizes the potential for HSR to be a transformative agent in the realm of economic development. This project encapsulates the aspirations of two dynamic Southeast Asian economies, united in their pursuit of sustainable growth, enhanced connectivity and global competitiveness. By scrutinizing the KL-SG High-Speed Rail through the lens of economic benchmarking, a deeper understanding emerges of how such projects can drive progress in areas such as cross-border trade, tourism, urban development and technological innovation.

Qiliang Li, Yuqing Sun, Menghan Ouyang et al.

Abstract Segregated incompressible large eddy simulation and acoustic perturbation equations were used to obtain the flow field and sound field of 1:25 scale trains with three, six and eight coaches in a long tunnel, and the aerodynamic results were verified by wind tunnel test with the same scale two-coach train model. Time-averaged drag coefficients of the head coach of three trains are similar, but at the tail coach of the multi-group trains it is much larger than that of the three-coach train. The eight-coach train presents the largest increment from the head coach to the tail coach in the standard deviation (STD) of aerodynamic force coefficients: 0.0110 for drag coefficient (C d), 0.0198 for lift coefficient (C l) and 0.0371 for side coefficient (C s). Total sound pressure level at the bottom of multi-group trains presents a significant streamwise increase, which is different from the three-coach train. Tunnel walls affect the acoustic distribution at the bottom, only after the coach number reaches a certain value, and the streamwise increase in the sound pressure fluctuation of multi-group trains is strengthened by coach number. Fourier transform of the turbulent and sound pressures presents that coach number has little influence on the peak frequencies, but increases the sound pressure level values at the tail bogie cavities. Furthermore, different from the turbulent pressure, the first two sound pressure proper orthogonal decomposition (POD) modes in the bogie cavities contain 90% of the total energy, and the spatial distributions indicate that the acoustic distributions in the head and tail bogies are not related to coach number.

Xiaofeng Hua, Lei Sun, Huaqiong Liu

Railroad transportation is an efficient and economical way of cargo transportation. Due to the imbalance of supply and demand in the railroad freight market, various factors have complex forms and different degrees of influence on the freight volume, which makes the forecasting of the railroad freight volume complexity and non-linear characteristics. This paper combines grey relation analysis and BP neural network to forecast the national railroad freight volume. Firstly, the data of the factors affecting the railroad freight volume from 2012 to 2022 are selected, and the grey relation analysis is used to obtain the relatively high correlation of the four influencing factors, namely the proportion of highway freight volume, the proportion of water freight volume, the mileage of railroad operation and the value added of the primary industry, which are used as the input layer of the BP neural network; then, according to the corresponding relationship between the influencing factors and the volume of railroad freight volume, the model is trained; finally, the model based on the model of railroad freight volume is trained; and the model based on the model of railroad freight volume is trained. Then, the model was trained according to the correspondence between each influential factor and railway freight volume; finally, the grey relation-based BP neural network model was compared with the traditional BP neural network model. Finally, the grey relation-based BP neural network model is compared with the traditional BP neural network model. The results show that the grey relation-based BP neural network can not only get better solutions, but also shorten the training time.

O. Ablyalimov, A. Osipov, D. Kurilkin

The paper presents the results of research on the justification of parameters of transport operation of three-section main (train) UzTE16M3 freight diesel locomotives on the high-speed railway section Marokand- Kattakurgan of JSC “Uzbekistan Temir Yullari” when moving freight trains without stops and with stops at intermediate stations, passing points, and separate points. The specified results were obtained by methods of locomotive traction theory in the form of tabular data, graphical dependences, and regression equations for determining logistical kinematic parameters of freight train traffic and the main energy efficiency indicators of the investigated diesel locomotives in a given section. The research results obtained by the authors can be used by drivers - instructors in thermal engineering and specialists of linear enterprises of JSC “Uzbekistan Temir Yullari” locomotive complex, whose professional and production activity is connected with the issues of saving of natural diesel fuel consumption by diesel locomotives on high-speed sections of the railroads.

Хлуднев Александр Александрович

The article is aimed at describing the tool of process analytics in the re-engineering of technological operations in the operation of railway transportation of an industrial enterprise. Efficiency improvement in process management is considered on the basis of their structuring with subsequent visualization. In particular, the article presents a target model of unsuitable railway rolling stock management aimed at reducing the risks of failure to fulfill the sales plan of industrial enterprises, where railway transportation dominates in the shipment of finished products.

YANG Fengping, ZHOU Mingzhi, CHENG Quan et al.

For the traditional PI controlled urban rail hybrid energy storage system, there are problems such as cumbersome parameter adjustment and lag in response to train start and stop conditions. An improved multi-step prediction control algorithm for urban rail hybrid energy storage system was proposed in this paper. The multi-step predictive current control loop was used to replace the traditional PI current inner loop to avoid the prediction error defect of single-step prediction and improve the dynamic response speed of the system. For the problem of large current ripple caused by non-zero equivalent duty cycle in the predicted current algorithm, the current fluctuation range at the optimal switching time was calculated in real time, and the switching action time was updated online. Finally, a hybrid energy storage system model for urban rail trains was built on the MATLAB/Simulink platform. The simulation results show that under the conditions of train acceleration and braking, the network voltage recovery time is reduced by 0.543 s and 0.644 s respectively, the overshoot is reduced by 5.98% and 4.83%, and the change rate of current ripple is significantly improved, which verifies the correctness and superiority of the strategy proposed in this paper.

Hans True, Lasse Engbo Christiansen, Andreas Lindhardt Plesner et al.

Abstract We investigate numerically the dynamical reactions of a moving wheelset model to real measured track irregularities. The background is to examine whether the dynamics are suitable as the input to the inverse problem: determine the true track geometry from measured wheelset dynamical reactions. It is known that the method works well for the vertical position of the rails but the computed lateral position is often flawed. We find that the lateral motion of the wheelset often may differ from the track geometry. The cases are investigated closely but the reasons remain unknown. While the wheelset dynamics reflect the larger (> 4–6 mm) aperiodic track disturbances and single large disturbances quite well, this does not seem to be the case for general smaller or periodic track irregularities or sections behind single large disturbances. The resulting dynamics of a wheelset to lateral track irregularities are in general not sufficiently accurate to be used as the basis for a description of the track irregularities.

Oleg Shelgunov, Vladimir Kavkazskiy

The materials presented in the article will be used in the dissertation submitted in partial fulfillment of the requirements for the degree of Ph.D. in Engineering Science. The article provides information on the construction and operation of a railroad tunnel for a high-speed railway line, it is noted that generally single-track railroad tunnels are constructed on new railway lines. A development review of existing methods for reducing and compensating aerodynamic pressure and ways of its regulation is given, and its advantages and disadvantages are analyzed. A new design solution description that helps to reduce the intensity of the aerodynamic effect is presented, the principles of its operation and the main hypothesis are described, and advantages over existing solutions are shown. The study materials of the aerodynamic state of the «tunnel-train» system, obtained from the numerical simulation results by the methods of computational fluid dynamics, are presented. An analysis of the change in aerodynamic pressure for various parameters of the passage of a train in a tunnel has been carried out, and the «tunnel-train» system state assessment has been given. The main attention is paid to the influence degree of the train speed, the cross-sectional areas ratio, and tunnel and train lengths. The numerical modeling results were evaluated by the aerodynamic pressure drop values, by the nature of the aerodynamic state of the «tunnel-train» system, by the nature of the air flows, and by its speed trajectories. The obtained results are presented in tabular and graphic forms, and results analysis is carried out. The effectiveness of a new design solution for a tunnel for a high-speed railway line in solving the problem of mitigating aerodynamic pressure is shown, and the rationality of the engineering solution is substantiated. The constructive solution of the tunnel for a high-speed railway line has the potential to reduce material consumption and improve the technical and economic characteristics of the structure and can be used in the design and construction for further efficient operation of perspective high-speed railway lines in modern conditions, with the account aerodynamic phenomena.

Renliang Guo, Yongjuan Zhang, Rui Qi

Based on the background of Qingdao subway tunnel underpassing the railway, the calculation model was established by ABAQUS computer simulation software to study the influence of tunnel construction and train disturbance on railway subgrade. Through ABAQUS and its DLOAD subroutine and Visual Studio programming, different train running speeds were realized, and the variation law of subgrade acceleration was obtained. BP neural network model was used to predict the peak acceleration of subgrade. The results show that with the increase of the speed of the vehicle, the peak acceleration of the subgrade increases continuously, showing a double hump distribution; the vibration acceleration generated by train operation has obvious influence on railway subgrade. BP neural network can accurately predict the peak acceleration of subgrade under the combined action of tunnel construction and train operation.

Hao Ling, A. Shabana

H Wang, Z. Guan, S. He

A. Polyanskiy

The article discusses theoretical and practical research in the field of evolutionary modeling application for solving construction works planning problems in the formation of railroad track technological construction process. The study is a part of the developed engineering and technical support subsystem for railway construction: engineering and intellectual support of railroad track technological construction process. This subsystem is based on the effective use of automated systems with artificial intelligence elements. Development and implementation of these automated systems are focused on achieving a single end result, such as a finished railroad track facility with suitable functionality within the established deadlines, planned working cost and labor costs, as well as meeting modern safety requirements throughout the entire operation period. Taking into account railway construction dynamic, the use of new materials and technologies, new trends were identified within the study scope in the field of technological processes operational development, and optimal work sequence determination in the railway facilities construction. In particular, the occurrence of deviations from the planned requirements in the construction work course requires a quick reconsideration of the decisions already made, due to the railway construction stochastic behavior. This is a forced measure to ensure the fulfillment of the planned targets. The existing methods allow to correct the construction work organization, however, the technology, and in particular, the technological process remains unchanged. The static nature of the technological process is largely dictated by the project documentation requirements and work safety. But modern advances in the information and intelligent technologies field, with the account of technological process structure variability, can give a technological process dynamic properties. The technological process's ability to adapt to changing work production conditions will provide flexibility in the railway facilities construction. To solve this problem, an automated evolutionary modeling mode and optimization of the railway facility construction technological process were used. The peculiarities of existing optimization methods, in terms of the dimension of the active task and taking into account several criteria, force us to turn to intelligent methods. The article describes a technological processes optimization method for the railway facilities construction using a genetic directed search algorithm in the space of solutions. In this case, several design constraints are taken into account: resource, technological, organizational, informational. For this, a computational and logical model was developed, which made it possible to assess the target function (fitness function), with the account of the dynamic distribution nature of the contractor's available resources for construction work. Based on the theoretical research results, the article presents the practical aspects of evolutionary modeling and optimization of the railway facilities construction technological process using a genetic algorithm on the example of the flooded railway roadbed embankment construction. The results presented in this article were obtained during the dissertation research made by the author.

Yu. M. Kulinich, S. A. Shukharev, A. V. Gulyaev

Currently, an asynchronous variable frequency drive based on semiconductor converters is widely used due to the relative simplicity and reliability of the design. The use of digital microprocessor systems ensures high accuracy and flexibility of drive control. On the domestic rolling stock, the widespread introduction of asynchronous motors began to replace DC traction motors with sequential excitation. In particular, scalar-controlled asynchronous motors are used on serially produced 2TE25A diesel locomotives and EP20 electric locomotives. The auxiliary asynchronous machines of these locomotives are controlled by the vector control method. The use of a new type of engine on the rolling stock makes it possible to achieve a significant increase in the quality of consumed energy and reduce the consumption of electricity for traction of trains. Ensuring the energy efficiency of the drive in a wide range of loads requires further research. In this regard, the issue of saving energy resources becomes very urgent. The article proposes a vector control scheme for asynchronous motors of auxiliary machines of an electric locomotive, which implements an extreme method of control according to the criterion of minimizing the consumed current. The analysis of the engine operation is carried out based on its mathematical model in a rotating coordinate system d — q, which is implemented in the MatLab/Simulink software package. As a result of simulation modeling, it was found that the extreme control system with a variable step allows for each fixed value of the electromagnetic moment of the motor in the minimum time to find the optimal (extreme) value of the magnetic flux of the motor rotor, which corresponds to the minimum value of the stator current. The developed model of the motor with vector control is supplemented with an extreme regulator device, which allows achieving the best energy performance of the motor and reducing electrical losses in all operating modes with a minimum search time. The presented research results can be used in the development of energy-saving control systems for an asynchronous motor.

A. B. Rezende, S. T. Fonseca, D. J. Minicucci et al.

Peng Guo, Limin Wang, C. Xue et al.