最新刊期
卷 ， 期 6 ， 2023
- 摘要：The pantograph slide is the core equipment for the train to obtain energy, and the good performance of its material is the key to ensuring the trains' safe and stable operation. With the further improvement in speed of high-speed trains that are characterized by high power, high capacity, and long-distance operation, higher requirements has been put forward for the performance of pantograph slide materials. This paper starts with an overview of the development history of pantograph slide materials in China and abroad, including metal slide plates, pure carbon slide plates, powder metallurgy slide plates, metal-impregnated carbon slide plates, and composite slide plates. The processing technologies, as well as pros and cons are also reviewed for these pantograph slide materials at different stages of development. This paper concludes by outlining the prospects for the future development of high-performance pantograph slide materials, taking into account the actual development conditions of China's electrified railways.关键词：high-speed train;pantograph slide;pantograph slide materials;research progress
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发布时间：2024-08-02
General
- 摘要：Based on the analysis on structural and dynamical characteristics of movers in linear induction motors and permanent magnet synchronous motors, this paper explored the change rules of mover motions of swaying, bouncing, rolling, yawing and pitching in the starting, coasting, and braking states, by developing the dynamical models with the multi-body dynamics simulation software for ultra-high-speed (1 000 km/h) electromagnetic propulsion devices respectively in the above two drive types. The final results show that the normal force applied on the induction mover facilitates automatic lateral alignment of the mover and resistance to lateral impact, while inhibiting rolling and yawing of the mover. In the scenario of the permanent magnet mover, the normal force from the motor aligns with the direction of mover deviation. Consequently, the mover moves close to the guideway under the impact of lateral irregularity without restraining rolling and yawing effects. Due to the vertical irregularity of the guideway, the induction motor mover experienced notable vertical vibration and impact, while the vertical component force applied by the motor on the permanent magnet mover mitigates vibration to some extent. This paper concludes that running states significantly affect the vertical response and pitch motion of the two types of movers, and the maximum vertical displacement, acceleration, and impact force all occur during braking for both.关键词：ultra-high-speed maglev;electromagnetic propulsion;linear motor;mover;dynamics
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发布时间：2024-08-02 - 摘要：The permanent magnet electrodynamic levitation system has been proven significantly valued for applications in ultra-high-speed tube magnetic levitation transport, due to its self-stabilizing performance at high speeds and easy installation and maintenance. This paper focused on the ultra-high-speed permanent magnet electrodynamic levitation system and presented a method for constructing boundary conditions for transverse end sections, by modeling the "Halbach permanent magnet array—conductor plate" structure. Additionally, a method to solve the electromagnetic force was proposed. By analyzing the change rules of electromagnetic force with electromagnetic parameters and structural parameters, this paper revealed the characteristics of electromagnetic force. The principle of the electromagnetic force model was validated through a comparison between the finite element simulation results and findings from a verification experiment carried out on a rotary experimental platform.关键词：permanent magnet electrodynamic;tube magnetic levitation;Halbach permanent magnet array;electromagnetic force characteristics
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发布时间：2024-08-02 - 摘要：In order to improve the operational safety and save maintenance costs of rolling stock, this paper focused on the fatigue remaining life of rolling bearings for rolling stock, further investigated their service life rules, and identified the basic types of bearing service lives, namely fatigue life, precision life, and abnormal damage resistance life. Through statistics and analysis on the accuracy and probability of abnormal damage on rolling stock bearings before and after service operations, it established the relationships of bearing accuracy and abnormal damage survival rates associated with mileage, resulting in a mathematical model. Additionally, based on analysis on the variation laws of precision life and abnormal damage resistance life, it summarized total capacities of bearings applied in batches in different service life stages. This paper underscores the available value in the remaining life of bearings when applied in batch, and proposes suggestions for reasonable management of bearing service life.关键词：rolling stock;rolling bearings;service life;precision life;abnormal damage resistance life;remaining life
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发布时间：2024-08-02 - 摘要：Intelligent diagnosis method based on convolution neural network (CNN) has been widely used in bearing fault diagnosis. However, most existing diagnostic models rely on single-source information inputs, limiting their accuracy and reliability. To solve this limitation, this paper presents a rolling bearing fault diagnosis method based on dual-channel feature fusion. Firstly, the time-frequency analysis diagrams of rolling bearing vibration signals were constructed by using multiple Q-factor continuous Gabor wavelet transform (CMQGWT) and fast spectral coherence (Fast-SC), respectively. Subsequently, a CNN model with dual input channels was constructed, allowing for the fusion of deep time-frequency features extracted from each channel into a new feature at a feature fusion layer. Finally, the diagnosis results were output using a classifier. Through classification and recognition experiments involving single and compound faults in rolling bearings for high-speed trains, compared with the CNN model with a single input channel, the proposed model demonstrates superior diagnostic accuracy and robustness.关键词：rolling bearing;convolution neural network;feature fusion;fault diagnosis;high-speed train
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发布时间：2024-08-02 - 摘要：A study was conducted on the contact characteristics and parameter optimization of the wheel axle sliding bearings in 1 435/1 520 mm variable gauge bogies for high-speed trains. The magnitude of interference for the fitting of the 'wheel - sliding bearing' and 'sliding bushing - axle' was determined in accordance with GB/T 5371—2004. Based on the joint simulation with HyperMesh and ANSYS, the materials for sliding bearings and sliding bushings, as well as the optimized structural parameters of sliding bearings, were determined. The research results indicate that using 45# steel as the sliding bearing material and polyamide-imide (PAI) as the sliding bushing material can effectively reduce the contact pressure between the two; the average contact pressure between the wheel and the sliding bearing increases approximately linearly with the inclination angle of the sliding bearing slope, while the maximum contact pressure between the sliding bearing and the sliding bushing initially decreases and then increases; chamfering at points a and c of the contact part between the wheel and the sliding bearing can effectively alleviate stress concentration resulting from abrupt changes in structural geometry; when the axle is subjected to bending deformation due to radial load, a deflection torque around the x-axis would be generated on the sliding bearing; chamfering at point b of the sliding bearing can effectively improve the contact state between the sliding bearing and the sliding bushing.关键词：high-speed train;sliding bearing;sliding bushing;interference fit;chamfering radius;contact pressure
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发布时间：2024-08-02 - 摘要：Rail breakage and expansion resulting from changes in longitudinal displacement of the steel rail pose a significant threat to train safety. To address the need for high-precision, non-contact and multi-rail displacement detection, an online monitoring method for multi-rail longitudinal displacement based on rotary laser sensing was proposed in this paper. Angular gauge plates fixed on rails were used to convert the longitudinal displacement of rails into lateral displacement of gauge plates, and the lateral displacement of rail gauge plates were then captured by the rotary laser sensor. On this basis, a groove feature recognition method utilizing a sliding window threshold was proposed to ensure accurate and stable measurement of the lateral displacement of gauge plates. Finally, the developed rail displacement monitoring system was deployed for long-term testing at K730+000 on the Lanzhou-Urumqi railway in Jiayuguan city, Gansu province. The test results show that the proposed method could ensure long-term and reliable online monitoring and early warning of longitudinal displacement for multiple rails.关键词：multi-rail longitudinal displacement;online monitoring;laser sensing;gauge plate feature recognition;high-speed railway
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发布时间：2024-08-02 - 摘要：The secondary suspension parameters of locomotives have a significant influence on the stability of heavy-haul couplers under compression. This paper aimed to explore the reasonable matching between 102-type couplers and the secondary suspension parameters of heavy-haul locomotives. A detailed two-locomotive dynamics model was established by using SIMPACK software, incorporating a 102-type coupler and HXD1 eight-axle heavy-haul locomotives. The mechanical characteristics of the coupler and the safety performance of the heavy-haul locomotives were analyzed under different calculation conditions. Moreover, the influence of secondary suspension parameters on locomotive safety was compared at different coupler free angles and under varying longitudinal forces. The results indicate that at low longitudinal pressure, the coupler angle stabilizes at a free angle, and the lateral force on the locomotive's wheel axles increases with an increasing free angle of the coupler and a higher lateral stiffness of the secondary suspension. This relationship was independent of the longitudinal force of the coupler. As the longitudinal coupler pressure increases, resulting in deflection to overcome the pre-compression load of the restoration block, the coupler angle further increases. At this stage, an appropriate increase in the lateral stiffness of the secondary suspension helped to maintain coupler stability along with just a minimal impact. In order to secure safe train operation in braking conditions, it is recommended to control coupler free angles within 6°, and set the lateral stiffness of the secondary system on a single side of bogies within the range of 0.45-0.60 kN/mm. Additionally, the recommended secondary lateral stop clearance includes a 35 mm free clearance plus a 5 mm elastic clearance.关键词：heavy-haul locomotive;102-type coupler;stability of coupler under compression;parameter optimization;coupler free angle;stop clearance
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发布时间：2024-08-02 - 摘要：Wheel tread wear is an important parameter to evaluate the operational safety of locomotives, yet timely and accurate monitoring is often lacking at wheel operation and maintenance sites. To this end, this paper proposed a prediction algorithm of tread wear for locomotive wheels based on GA-ridge regression analysis (hereinafter referred to as the "GA-ridge regression” prediction algorithm). This algorithm consisted of two steps: data pre-processing and data-based prediction analysis. In the first step, collected tread wear data was classified according to different measurement methods, and characteristics of different data types were analyzed considering the actual operation and maintenance of wheels. The classified data was then sliced using the profiling cycle as the data partitioning criterion, followed by cleaning and noise reduction of the corresponding dynamic measurement data by relevant criteria and principal component analysis. In the second step, data was integrated into datasets, and a time-sliding window was created for the training set data. The ridge regression algorithm was used to train the training set data for regression analysis, and the model parameters were tuned using a combination of the genetic algorithm and the validation set data to improve the prediction accuracy. The test set data was used for prediction by the traditional prediction algorithm, ridge regression linear prediction algorithm, and GA-ridge regression prediction algorithm respectively to compare and analyze their prediction effects. Additionally, a comparative analysis was conducted using the same evaluation method and sample wheels in an expanded size to further assess the prediction effects. The results indicate relatively lower prediction errors and standard deviations of errors when using the GA-ridge regression prediction algorithm. This research concludes that the GA-ridge regression prediction algorithm provides higher prediction accuracy and better prediction stability.关键词：locomotive wheels;wheel tread wear prediction;principal component analysis;ridge regression;genetic algorithm
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发布时间：2024-08-02 - 摘要：By analyzing and comparing the application scenarios and service targets of the large-capacity and medium-capacity maglev trains and light tour maglev trains, the top-level design indicators of the light tour maglev trains was defined based on the elements such as functions, safety, environment and economy, and studied the general design and the main system design of the train. Based on the requirements of train traction and levitation capacity, the overall framework of the running mechanism was designed and developed a scheme of a single car being equipped with two levitation frames, reducing the unsprung weight of the train and the difficulty of equipment maintenance and increasing the space for the equipment under the car. To achieve the goal of "reaching peak carbon emissions and carbon neutrality", a plan to supply power for the light tour maglev train by train-mounted batteries was proposed, which avoided the current receiving of power supply rail and reduced the cost of line construction. The design scheme of each subsystem of the train by theory and simulation was verified, proving the feasibility of the general design of the train. The scheme of the light tour maglev train is innovative, economical, feasible and practical, which can provide inspirations and methods for the design of various types of maglev trains.关键词：light maglev;tour;two levitation frames;low cost;train-mounted energy storage
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发布时间：2024-08-02 - 摘要：During the operation, the resonance fatigue of the structure is easily caused by the high-frequency wheel-rail excitation. In this study, the vibration fatigue test with a metro cowcatcher was conducted for the fatigue cracking found in a certain metro cowcatcher. It was found that the resonance fatigue of the structure was mainly caused by the rail corrugation with the frequency of 93 Hz on the line. Given the high cost and limited number of sensors in the experimental research method, a method to assess the life of the metro cowcatcher in the reproduced multi-axis vibration environment was proposed based on the simulation analysis. Firstly, a random vibration model of the cowcatcher was created based on the pseudo-excitation method, which can well reproduce the actual vibration environment of the cowcatcher. Then, the modal damping ratio was optimized by the genetic algorithm, improving the consistency between the simulation and measured response results, and proving the correctness of the modeling method. At last, the whole-course damage and fatigue life of any part of the cowcatcher was calculated by the multi-core parallel computing method, significantly improving the efficiency of simulation calculation. The results show that the weld corner of the cowcatcher is the weakness of the structure, the whole-course damage under operating condition is 6.25E-03, and the fatigue life is 6000 km, which is far lower than the design life of 3 600 000 km. The location of the largest damage on the cowcatcher found by the above method is the same as that of the actual damage to the structure, further proving the correctness of this method.关键词：metro vehicle;fatigue test;multi-axis vibration model of cowcatcher;genetic algorithm;parallel computing;fatigue life
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发布时间：2024-08-02
Railway Rolling Stock
- 摘要：It is necessary for the starting control strategy of metro trains to ensure that there will be no backward sliding when the train starts in the whole line, and that the starting impact is as small as possible and shall be not more than 0.75 m/s3, and the starting time is as short as possible. Based on the existing control strategy that a train braking mitigation command should be sent when the train traction reaches a certain threshold, an optimized control strategy for sending such command was proposed when the traction reached a certain threshold according to the train traction brake characteristic parameters and worked out the level value when the train braking mitigation command was sent by creating the starting acceleration model and the force model of the train at the time of backward sliding. The theoretical analysis and site test show that the optimized strategy proposed herein can significantly reduce the vehicle starting impact and improve the starting efficiency under the premise that the train will not slide backward when it starts in the whole line. This optimized strategy can be used as a reference for the starting control strategy of metro trains. According to the different traction brake characteristics, different level thresholds for the sending of holding brake mitigation command can be worked out.关键词：metro trains;starting control;traction brake characteristics;optimization;brake mitigation
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发布时间：2024-08-02 - 摘要：Linux embedded operating system is installed on the host devices on the train. All the external applications need to access the kernel via system calls. With the increasing compatibility and openness of the train communication network, there is a risk of cyberattacks on the train-mounted host devices. In case of a cyberattack, the malware will interact with the kernel via the system call and leave a trace. Therefore, the train-mounted host device intrusion can be detected based on system call sequence. In this paper, the structure of Linux system and the principle of system call sequence were analyzed, the original data feature processing methods including feature extraction, bag-of-words, inverse-frequency processing and dimension reduction were designed, and an intrusion detection model based on Grid Search-K-Nearest Neighbor (GS-KNN) was created. The experimental results show that the accuracy of the method designed in this paper is 96.62%, and the method has certain advantages compared with other lightweight algorithms and can detect the network intrusion effectively.关键词：system call;intrusion detection;KNN;train-mounted host devices
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发布时间：2024-08-02
Electric Traction and Control
- 摘要：To mitigate the impact of high-speed maglev harmonics on the traction power supply network and address the time lag in harmonic control, predicting harmonic current is commonly necessary. In this context, a superior alternative to traditional algorithms is a combined model that integrates deep learning algorithms. In this paper, a new multi-agent maglev harmonic prediction algorithm with integrated attention mechanism was proposed. The algorithm optimized the parameters of variational mode decomposition (VMD) by sparrow search algorithm (SSA), and used these optimized parameters to decompose the original current signal into harmonic components with different center frequencies. Subsequently, all components were input into the long short-term memory (LSTM) network of the integrated attention mechanism for time series prediction, and multiple independent prediction agents were formed, followed by the reconstruction of each agent's prediction results, so as to predict the harmonic current of the high-speed maglev. On this basis, the error correction mechanism was introduced to enhance the prediction accuracy of the model. Theoretical analysis and simulations of Shanghai high-speed maglev traction system were conducted, with the grid-side current data collected for experiment and analysis using the proposed algorithm model. The results indicate that, compared with other models, the proposed prediction model demonstrated superior performance in predicting maglev harmonic current, with the potential for further reducing the time lag.关键词：harmonic prediction;sparrow search algorithm;variational mode decomposition;long short-term memory neural network;attention mechanism
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发布时间：2024-08-02 - 摘要：High-naturalness text-to-speech is one of the basic requirements for advanced intelligence in vehicle-mounted human-machine interaction. Currently, in the rail transit field, there is widespread use of traditional low-naturalness text-to-speech algorithms, which are out of touch with the rapidly developing intelligent human-machine interaction technology. In contrast, end-to-end deep learning-based text-to-speech algorithms, with their nearly human-like naturalness, have become dominant in various fields of text-to-speech. This paper introduced an end-to-end deep learning-based text-to-speech algorithm suitable for offline railway vehicle environments. The mean opinion score of this algorithm reached 4.18, and the real-time rate on the vehicle-mounted embedded hardware platform NVIDIA Xavier reached 0.52. Experiments show that this algorithm not only outperforms traditional text-to-speech algorithms in terms of subjective performance such as naturalness, but also possesses engineering practicality in the offline vehicle environment of railway transportation.关键词：rail transit;vehicle-mounted human-machine interaction;intelligent;deep learning;end-to-end text-to-speech
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发布时间：2024-08-02 - 摘要：To guide the operation and maintenance (O&M) of the urban rail transit vehicles precisely, it is necessary to collect the latest vehicle status data and predict the development trend. Therefore, it is essential to conduct data mining and analysis for the real-time operation data and the historical O&M data of the vehicles in the same time and space, and enable the users to create and modify the data analysis model without the ability to write code. The model can run automatically and output the results to provide a basis for the vehicle status judgment. To this end, a set of vehicle data engine system was designed based on the big data platform and intelligent perception to clean and integrate the operation data of the traction, braking, door, network and LCU systems for the spatial and temporal alignment of data. In addition, data analysis strategy model was developed by means of drag and drop based on the canvas components to carry out multidimensional data analysis, make decisions, monitor the working process, identify hidden troubles and give early warning, and make life predictions, replacing the repetitive and complex manual operation. It can also provide functions such as data analysis custom editing, automatic analysis, automatic warning, troubleshooting guidance, and spare parts procurement, thus achieving multi-discipline data fusion, integrated data supervisory control, fault linkage analysis, data statistical analysis, automated processing analysis, result output, deduction and prediction, integrated decision-making and visual display, providing data support for the development of maintenance modes and strategies, further ensuring the safety of metro trains, improving the train reliability, and reducing the operating costs.关键词：operation and maintenance data;components;intelligent analysis;custom editing;data engine;quality and efficiency improvement;urban rail transit vehicles
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发布时间：2024-08-02 - 摘要：To mitigate longitudinal impulse and address challenge posed by continuous air braking operations in long and steep downhill sections for 20 000-ton heavy haul combined trains, this paper proposes an approach for operation optimization of such trains featuring a long formation in such sections based on a data-driven algorithm. An air braking force prediction model was developed based on neural network learning focusing on the variation rules of air braking performance across different operating states, to incorporate differences in air braking characteristics across different trains and varied braking system states on same trains. Then, an operation optimization algorithm was designed, establishing a reward function that prioritized speed following features, based on reinforcement learning. This algorithm incorporated constraints including train traction/electric braking characteristics, braking application and release times of train pipes, speed limits, and operational smoothness, to optimize the operation strategy for heavy-haul combined trains in long and steep downhill sections by reinforcement learning. The proposed air braking simulation model and operation optimization algorithm were verified using data collected from operation of real trains, confirming their feasibility and rationality. The results show the effectiveness of the proposed air braking force prediction model in predicting performance of air braking systems on running trains. Compared to manual driving, the optimized operation strategy plays an effective role in reducing longitudinal impulse and maximum coupler force to ensure the safety during train operation.关键词：heavy-haul combined train;air braking;long and steep downhill;neural network;reinforcement learning;heavy-haul rallway
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发布时间：2024-08-02
Intelligent Technology
- 摘要：In order to ensure the operational safety of interlocking systems within cloud platforms, this paper presented a redundant structure for cloud-based interlocking systems based on virtual machine fault tolerance technology, through analyzing the redundant structure of the existing computer-based interlocking systems and considering the characteristics of cloud platforms. Firstly, the characteristics and advantages of the redundant structure of cloud-based interlocking systems were elaborated. Subsequently, this paper analyzed the working mode and server failure factors, and established a server fault tree model and dynamic fault tree model to evaluate the probability of failure on danger (PFD) and probability of failure to safety (PFS). Finally, the reliability of the redundant structure of cloud-based interlocking systems was assessed by simulation analysis using the dynamic fault tree model. The results indicate that cloud platforms are more suitable for deploying interlocking systems in multiple redundant structures such as MooN structures. This research on the redundant structure for cloud-based interlocking holds certain reference significance for the development of cloud-based interlocking systems.关键词：railway interlocking system;cloud computing;redundant structure;dynamic fault tree;failure probability;high-speed railway
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发布时间：2024-08-02
Communication and Signal
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