最新刊期
卷 ， 期 1 ， 2024
- 摘要：Scientific maintenance of operating vehicles and ensuring the safety of train operations have always been the core issues in the field of rail transit. In recent years, with the major demands of predictive maintenance and unmanned driving, there is an urgent need to realize the PHM (prognostics and health management) functions of holographic state perception, elaborate diagnosis and prediction, and timely feedback and disposal for railway trains. The existing system frameworks suffer from perception inefficiency, insufficient fusion, poor model optimization dynamics, weak computational synergy, and low levels of autonomous decision-making, etc. The development of advanced IoT, big data, artificial intelligence, digital twins, and other technologies has pushed the PHM system frameworks of railway trains to evolve to a higher level of intelligence. In this paper, the technical development stage of PHM systems of railway trains is reviewed and categorized. Furthermore, the PHM 4.0 framework for railway systems, which leverages ubiquitous sensing and collaborative computing, has been introduced. This framework is described in detail, elucidating its foundational principles, system structure, and key technologies. The paper also outlines the approaches, techniques, and anticipated outcomes associated with the deep integration of ubiquitous sensing, collaborative computing, and health management. Additionally, it clarifies the primary focus of current technological research, supporting enhanced safety and maintenance quality in railway operations.关键词：rail transit;prognostics and health management 4.0 systems for railway trains;ubiquitous sensing;collaborative computing;intelligent operation and maintenance;unmanned driving
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发布时间：2024-08-02 - 摘要：With the continuous development of technologies such as perception, decision, control, and diagnosis towards intelligence, the integration of intelligent features into vehicular applications has emerged as a prominent trend in the future development of rail transportation. This paper provides a comprehensive overview of the current status and future expectations of key onboard technologies, including automatic train operation (ATO), active collision prevention, infrastructure detection, and driver behavior monitoring. These technologies have significantly enhanced the operational efficiency and safety of rail transportation, along with profound potential for further advancements. Specifically, the train automatic operation technology aims to achieve more accurate and efficient operation of trains, thereby significantly reducing the risks associated with human operational errors. The active collision prevention technology enables automated avoidance between trains, such effectively precluding collision accidents. Furthermore, the infrastructure detection and driver behavior monitoring technology facilitates timely warnings in cases of equipment failure or driver fatigue, ultimately reducing potential hazards. With the further application of these technologies, rail transit vehicles will witness further innovation and development based intelligence, providing robust support for efficient, safe, and intelligent operation of rail transportation in the future.关键词：rail transit;automatic train operation;active collision prevention;infrastructure inspection;behavior monitoring
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发布时间：2024-08-02
General
- 摘要：This paper analyzed the effect of train quantity on the train longitudinal impulse experienced, by establishing a longitudinal dynamics simulation model of the 20 000-ton heavy-haul trains on the theory of longitudinal dynamics and offers recommendations for mixed marshaling of long and short consists. Moreover, this study included calculations on delays in air braking application and release, as well as the maximum coupler force in cycle braking conditions under three scenarios: synchronous reduction of front and rear wagons, reduction of only front wagons, and reduction of only rear wagons. The latter two scenarios represent mixed marshaling of long and short consists. The results reveal the following findings for 20 000-ton heavy-haul trains in a “1+1+controllable train tail” formation. Synchronous reduction in front and rear wagons effectively mitigates release delay and maximum coupler force during the release process. Reduction of only front wagons results in a small change in the maximum release delay and fails to sufficiently reduce longitudinal impulse. Conversely, reduction of only rear wagons considerably diminishes the maximum release delay and significantly mitigates longitudinal impulse. These findings offer valuable guidance for optimizing heavy-haul train formations. Therefore, for mixed marshaling of both long and short consists, coupling a short consist at the rear of a long one is an effective solution to reduce longitudinal impulse during train operation.关键词：longitudinal impulse;heavy-haul trains;train quantity;air braking;longitudinal dynamics
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发布时间：2024-08-02 - 摘要：In order to improve crashworthiness of electric locomotives, this paper presents a dynamic topology optimization study aimed at improving the crashworthiness at the underframe's front end of a certain model of electric locomotives. Firstly, a finite element model of the electric locomotives was established, and the main path of energy flow in the underframe was identified by dynamic topology optimization analysis based on hybrid cellular automata. Then, according to the structural characteristics of the electric locomotive body, the front-end structure of the underframe was optimized in design and the inclusion of aluminum honeycomb energy absorbing materials. Finally, the finite element models before and after optimization were compared through the collision simulation calculation. The results reveal a significant reduction in peak acceleration, with the optimized car body at 402.56 m/s2, which is 39.29% lower than value before optimization of 663.04 m /s2. Additionally, the peak interface force upon collision is reduced by 35.71% after optimization. These findings demonstrate the rationality and effectiveness of topology optimization design in improving the crashworthiness of this specific locomotive model's structures.关键词：electric locomotive;crashworthiness of locomotive;dynamic topology optimization;hybrid cellular automata;aluminum honeycomb
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发布时间：2024-08-02 - 摘要：3 150 kW AC drive diesel locomotives have been developed in alignment with the requirements for export to Australia. This paper first gave an overview of the general layout, main performance parameters, configuration, and traction performance curve, and highlights the characteristics of this locomotive model including its adhesive traction performance, lightweight and high-strength carbody, electromagnetic compatibility performance, noise control, and diesel auxiliary system. It also focused on the testing and verification processes conducted, including carbody static strength tests, torsion tests, noise tests in driver's cab, electromagnetic compatibility tests, demonstrating the compliance with internationally advanced standards in relevant performances of this locomotive model. This paper emphasized the advancements achieved with the 3 150 kW AC drive diesel locomotive model specifically tailored for export to Australia and the positive influence on the design of diesel locomotives.关键词：internationally advanced standard;3 150 kW;AC drive;diesel locomotive
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发布时间：2024-08-02 - 摘要：In this paper, the structural characteristics of the power pack in dual-power high-speed multiple-unit trains were present‐ ed. The finite element model of the power pack frame was established using HyperMesh, and the static strength and fatigue strength con‐ ditions of the power pack frame were determined based on EN 12663-1. The static strength of the power pack frame structure was evalu‐ ated using Von mises stress theory, and the welding fatigue strength according to DVS 1612. ANSYS software was utilized for free mode analysis of the power pack frame, while a dynamics model was developed on the basis of the double-layer vibration isolation theory. Vi‐ bration intensity of the power pack was calculated following ISO 10816-6, and vibration tests were conducted on the power pack frame in accordance with ISO 8528-9. Through simulation analysis and vibration tests on the power pack frame, the results show that the power pack frame satisfies the design requirements specified by relevant standards.关键词：high-speed multiple-unit trains;power pack;static strength;fatigue strength;modal analysis;vibration isolation efficiency;vibration intensity
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发布时间：2024-08-02 - 摘要：The performance of the air supply duct, a crucial component of subway trains, significantly influences passenger comfort. Therefore, optimizing the structure of the air supply duct to enhance air supply uniformity has become an urgent concern. This study focused on improving indicators such as air supply volume, uniformity and noise through the optimization of the air supply duct structure based on theoretical design and computational fluid dynamics (CFD) simulation verification. First, to meet low noise requirements in the passenger compartment, the average outflow speed of the waist-shaped hole for converting dynamic pressure to static pressure was controlled at 5 m/s. Next, theoretical calculations of relationship between dynamic pressure and static pressure were conducted to control the dynamic pressure in the dynamic pressure chamber and the static pressure difference between the dynamic and static pressure chambers, ensuring air supply uniformity. Unlike traditional air duct structures with equal-width dynamic pressure chambers, the optimized air supply duct had a reduced diameter structure in the dynamic pressure chamber, which could improve air supply uniformity. To verify the accuracy of the theoretical design method, CFD calculation software was employed to analyze the flow field simulation of the theoretically designed optimized air duct structure. The optimized air duct model and the original air duct model were both incorporated into the same passenger compartment model, and the simulation results of the two coupled models were compared and analyzed. The findings demonstrate that the air supply uniformity of each waist-shaped hole in the optimized air duct structure was controlled within 20%, significantly improving the air speed distribution in the passenger compartment. This further validated the effectiveness of the theoretical calculation and optimization method, providing valuable guidance for the engineering application of air conditioning ducts.关键词：subway train;air conditioning duct;uniformity;noise;numerical simulation
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发布时间：2024-08-02 - 摘要：This paper focuses on analyzing the dynamic characteristics of a newly designed mid-low speed maglev frame, capable of running at speeds up to 160 km/h, using a train dynamics model established by SIMPACK multi-body dynamics analysis software, un‐ der both straight track and curve conditions. The results showed that the train reached 160 km/h under the straight track condition, while meeting the required levitation gap, carbody vibration acceleration, and other performance indicators. However, the performance indica‐ tors of the train deteriorated at 120 km/h. A frequency analysis was conducted specifically on carbody vibration acceleration, leading to optimization suggestions aimed at mitigating the impact of carbody resonance. Furthermore, under the curve condition, the train parame‐ ters including guiding force, lateral displacement of the air spring, and sliding table displacement all remained within the normal ranges. The study findings demonstrate the compliance of this newly mid-low speed maglev train with the requirements of the dynamics perfor‐ mance. The relevant dynamics results can provide data support for the follow-up research and subsequent engineering applications of this maglev frame.关键词：mid-low speed maglev train;maglev frame structure;dynamics;carbody vibration;urban rail transit
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发布时间：2024-08-02 - 摘要：A new type of motor rubber bushing with small radial-to-axial stiffness ratio for high-speed EMUs was designed to meet the installation requirements of motor suspension for a certain high-speed train unit. Through finite element simulation analysis, static stiffness test, fatigue test and running verification, the results show that rubber bushing with this structure can meet the technical requirements, and the pre-compression of rubber is simple and effective, the stiffness range is adjustable, the fatigue performance is good, and it can meet the high temperature tolerance of the motor operating environment.关键词：rubber bushing;radial-to-axial stiffness ratio;finite element;fatigue;high speed train
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发布时间：2024-08-02 - 摘要：In view of the difference in occupant damage between car crash scenarios and train collision scenarios, adjustable-angle lumbar spine and standing hip modules were developed based on the traditional automobile frontal crash test dummy (Hybrid III-50th dummy) with reference to the dummy structure of test device for human occupant restraint (THOR). Focus was given to the study of the biomechanical response characteristics of the upper and lower abdomens, and a train crash safety test dummy (H3-RS dummy) that can sit and stand was produced. This dummy possesses both the biomechanical characteristics of the Hybrid III-50th dummy and those of upper and lower abdomens, and so is more suitable for train crash safety test. Finally the preliminary verification test was carried out through the trolley test. The results demonstrate that the H3-RS dummy basically meets the test requirements in terms of structure, function, and strength.关键词：train safety;train crash;H3-RS dummy;biomechanical properties;abdomen;standing posture
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发布时间：2024-08-02 - 摘要：With the continuously increasing speeds of high-speed trains, the impacts of vibration and noise have become more significant. Consequently, there is an escalating demand for enhanced sound insulation performance and lighter design of interior wooden flooring in high-speed trains. This paper presented a design aimed at improving the sound insulation performance of interior wooden flooring with specific sizes. The design process initially involved the appearance and structure of particle dampers for the interior wooden flooring. The approach utilized the discrete element method to meet the installation requirements. Subsequently, an investigation was conducted into the sound insulation effects of various factors on the interior wooden flooring, including installation areas, particle materials, and particle sizes, through the calculations of energy consumption values for different particle damper configurations. This step identified an optimal configuration option. Finally, sound insulation tests were conducted to verify the effectiveness of the chosen option. The experimental data show the consistency between the sound insulation performance under different particle damper configurations and the discrete element simulation results, thereby demonstrating the effectiveness of the discrete element model. Moreover, the optimal particle damper configuration yields a significant improvement in sound insulation across all frequency bands, resulting in a weighted sound insulation increase of 3.9 dB. This result successfully achieves the desired goal and substantiates the efficacy of the particle damper in reducing vibration and noise in interior wooden flooring. The application of particle damping technology to address vibration and noise reduction in interior wooden flooring of high-speed trains provides a novel idea for vibration and noise reduction in structures similar to the interior flooring of high-speed trains, which has both important engineering significance and application value.关键词：interior wooden flooring in high-speed train;particle damping;discrete element method;sound insulation performance;high-speed EMUs
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发布时间：2024-08-02 - 摘要：Shenmu-Shuozhou railway is an important heavy haul freight railway line in China. Heavy haul trains run in harsh environments with great difficulties in operation. Train surge seriously affects train operation smoothness and safety. To address the surge of trains running on Shenmu-Shuozhou railway, the signal characteristics when surge occurs on heavy duty trains were analyzed, and a train multi-particle dynamic model based on elastic damping couplers was established. In addition, the running state of heavy haul trains with and without surge was simulated. A finite set predictive control method was proposed to eliminate the surge of heavy haul trains. The simulation verifies that the predictive control can reduce the speed fluctuation and the maximum coupler force during the surge of trains.关键词：heavy haul train;smoothness;surge;multi-particle model;finite set predictive control
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发布时间：2024-08-02 - 摘要：In the operation, high-temperature superconducting maglev trains are susceptible to the impact of random track irregularities. These irregularities cause vibrations of the carbody and maglev frame, which are transferred to the dynamic components of the linear motor, resulting changes in the air gap. The changed electromagnetic force reacts against the motor suspension system, causing further vibrations of the maglev frame and carbody. The coupled vibrations of both components influence the safe operation of high-temperature superconducting maglev trains to some extent. To mitigate the influence of random track irregularities on the motor suspension system, a multi-rigid-body dynamic theory model was established in this study. Through simulation verification of the dynamic response under periodic excitations, the correctness of the dynamic theory model was confirmed. Furthermore, within UM software, with the linear motor normal force and random track irregularities as external excitations, a simulation of the dynamics model of the high-temperature superconducting maglev train was conducted. The influence of the vertical stiffness of the motor suspension system on the air gap of the linear motor, the vibration of the carbody and suspension frame, and the train ride comfort was studied, and the optimal value for this stiffness was determined. The results show that increasing the vertical stiffness of the linear motor suspension system to a certain extent can improve the stability of the carbody. Additionally, increasing the vertical stiffness can reduce the variation in the air gap and motor vibration to a certain extent, thus decreasing the coupling effect with the suspension frame. The results obtained in this study are based on simulation analysis under specific structural parameters and load conditions, and they can provide valuable insights for the dynamic analysis of high-temperature superconducting maglev trains.关键词：random track irregularities;normal force;high-temperature superconducting maglev train;linear motor suspension;UM
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发布时间：2024-08-02
Railway Rolling Stock
- 摘要：This paper introduced the research progress and typical applications of power-concentrated EMUs abroad and provided a preliminary comparative analysis of system configurations among various EMU models. It presented overall objectives, technical characteristics, technical challenges, and technical solutions for the development of power-concentrated EMUs, in the context of the technological development and application status of power-concentrated EMUs in China. This paper focused on the analysis and development of key technologies for the design elements of power-concentrated EMUs, including traction, DC 600 V train power supply, and network control systems. Ground tests and field operation show the good performance of the proposed electrical system and its compliance with the requirements of various indicators for electrical systems of power-concentrated EMUs. Its successful development provides solid equipment support for improving the Chinese "Fuxing" EMU family and facilitating the China, s "going out" strategy of high-speed rail systems.关键词：power-concentrated EMU;electrical system;main circuit topology;network system;DC 600 V;coupled power generation
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发布时间：2024-08-02 - 摘要：The wide application of wireless communication technology has brought about an increase in network security risks for train communication networks. To mitigate these risks, data encryption has emerged as an important means, albeit with additional demand on CPU computing resources. However, train communication network hosts predominantly rely on embedded devices with limited computing resources. This paper proposes a lightweight encryption solution for train communication networks. This solution employs a key negotiation process based on traditional communication encryption scheme, aiming to achieve lightweight encryption in train communication networks and compliance with the authenticity, integrity, and confidentiality requirements of communication data, while greatly reducing hardware demands and computational burdens associated with key management. Experimental verification using the proposed solution yielded a key negotiation time consumption of about 31.9% and reduced the CPU load on devices to about 35.8% when compared to the traditional SM2+SM3+SM4 communication encryption method.关键词：train communication network;data encryption;lightweight;key negotiation
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发布时间：2024-08-02 - 摘要：Safety control system is a critical component within the safety function links on vehicles, playing an essential role in securing their overall safety. This paper presented an analysis of 3 typical architectures of safety control systems for urban rail transit vehicles, aiming to guide system design. Safety analysis and calculations were performed, taking into account potential common cause failure constraints across different architectures and incorporating data on hardware failures. Moreover, the impacts of different architectures on system failure rates and safety integrity levels (SIL) were examined. The calculation results indicate that, for the development of SIL3/SIL4 safety control systems, it is recommended to adopt a 1oo2 or 2oo3 system architecture, and special attention should be paid to common cause failures. The relevant findings serve as a reference and guidance for the subsequent design of safety control systems for urban rail transit vehicles.关键词：urban rail transit;safety function;safety architecture;failure rate;common cause failure;safety integrity level (SIL);urban rail transit vehicles
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发布时间：2024-08-02
Electric Traction and Control
- 摘要：As train intelligence continues to advance, numerous studies have emerged to explore lightweight techniques for object detection models on onboard equipment, for the purpose of improving calculation efficiency amidst limited resources. This paper proposed a parameter compression algorithm based on low-rank decomposition for the You Only Look Once (YOLO) series of object detection models, aiming to overcome the limited versatility of current lightweight treatment methods for these models. Initially, calculations were conducted to determine a low rank using the preset low-rank ratio coefficient along with the number of input and output channels of convolution units. Subsequently, a new convolution sequence was obtained by performing the Tucker decomposition to the convolutional layer of the target structure. Lastly, a new convolution sequence was fused to replace the original convolutional layer. Experiments were conducted on the proposed parameter compression method based on low-rank decomposition, using public datasets and three models, i.e., YOLOv5-l, YOLOv8-x, and YOLOX-x. While ensuring an average detection accuracy of the models based on low-rank decomposition over 96% compared to the original models, the number of parameters and float-point calculations of these models reduced by about 40%. The experiments resulted in a nearly 50% improvement in image detection speed. Further visual displays illustrated similar receptive fields on the same images between the compressed and original models. The experimental results show that the proposed method is effective in lightweight compression of single-stage object detection models of the YOLO series and can enhance their usability for onboard equipment. In addition, this study serves as a valuable reference for the lightweight treatment of other models in the automatic train operation scenarios of rail transit field.关键词：deep learning;low-rank decomposition;automatic train operation;lightweight treatment of model;object detection
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发布时间：2024-08-02 - 摘要：This paper presents a path recognition method based on binocular stereo vision for virtual rail train, to overcome the limitations of monocular vision and improve the path perception ability of virtual rail train. To achieve this, a lane detection model based on Mask R-CNN was developed, incorporating their characteristics such as obvious lane blocks, contour integrity, and unique shape. Meanwhile, a binocular matching algorithm based on multi-target tracking was proposed, addressing the drawbacks of general binocular matching algorithms including substantial computations and deficient ability to match repeated objects. The proposed method incorporated both left and right cameras to detect lane blocks respectively, and enabled the assignment of IDs through multi-target tracking. There features allowed for an orderly and directional binocular matching of lane blocks in the left and right images, and the reconstruction of three-dimensional coordinates of the path in the tram coordinate system. This method was demonstrated effective in improving the path perception ability of trams and providing more direct and accurate input information to enable various functions such as tracking control, autonomous positioning and relative pose estimation of trams. Additionally, experimental results show the high accuracy of the proposed method in 3D path reconstruction and its strong adaptability to different road conditions.关键词：virtual rail train;lane recognition;binocular stereo vision;target detection;multi-target tracking;binocular matching;3D reconstruction
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发布时间：2024-08-02
Intelligent Technology
- 摘要：In recent years, there have been large-scale incidents of abnormal wear on subway pantographs and catenaries across China, especially in winter. In 2022, more than 30 subway lines nationwide encountered this issue, resulting in economic losses amounting to hundreds of millions of yuan. In order to study the influence of environmental temperature on the pantograph-catenary relationship, a finite element model of the rigid catenary of a subway line was established. The stiffness curve of the catenary was calculated at ambient temperatures of -20~20 °C. The pattern of influence of environmental temperature on the stiffness of the catenary was analyzed. Then, a dynamic model of subway pantograph-catenary coupling with variable stiffness was established, and its accuracy was verified according to EN 50119 and other standards. The pantograph-catenary contact force was calculated under the conditions of ambient temperatures of -20~20 °C, train running speed of 40~90 km/h, pantograph static lifting force of 70~160 N, and stuck positioning clamps. Furthermore, the influence of environmental temperature on the pantograph-catenary contact force and the pantograph-catenary current collection quality was analyzed. The results show that there is a strong positive correlation between environmental temperature and the pantograph-catenary contact force and current collection quality. When the environmental temperature is below 0 °C, the pantograph-catenary current collection index will seriously deteriorate; stuck wire clamps will have a negative impact on the pantograph-catenary contact force and current collection quality, and the higher the train running speed, the greater the impact will be.关键词：rigid catenary;environmental temperature;stiffness curve of catenary;pantograph-catenary contact force;current collection quality;pantograph-catenary coupling dynamics
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发布时间：2024-08-02 - 摘要：Electrified railways using single-phase power-frequency AC systems have the advantages of pollution-free operation and high transportation efficiency. However, the current traction power supply systems face prominent challenges related to negative sequence and inefficient utilization of regenerative braking energy. Therefore, this paper proposed a power flow transfer topology for integrated hybrid energy storage systems. The analysis focused on the topology structure of the power flow transfer device (PFTD) for integrated hybrid energy storage, and delved into peak shaving, valley filling, regenerative braking, and in-phase operation modes, along with corresponding energy management strategies. Moreover, a coordinated control strategy was proposed, to reduce system losses, as well as further improve the utilization of regenerative braking energy and the control accuracy of peak shaving and valley filling. Additionally, a passive nonlinear current controller was introduced to improve the control response speed of converters. Finally, the simulation results indicate that the proposed system fully utilize the regenerative braking energy of the traction power supply system, improve the flexibility of energy flow in the system, and solved concerns related to negative sequence in the traction power supply system.关键词：electrified railway;negative sequence;regenerative braking energy;hybrid energy storage system;coordinated control;simulation
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发布时间：2024-08-02
Railway Electrification
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