To address the issue of poor contact between the lead wires of the ZPW-2000A track circuit tuning unit and the steel rails, a fault detection method for the tuning areaof the ZPW-2000A track circuit is proposed, based on the analysis of the receiver’ response under multi-source signal excitation during fault conditions. Initially, a transmission line model for the ZPW-2000A track circuit is established, and an enhanced nodal admittance time-domain equation is derived. The Laplace transform of the equation is subsequently applied to obtain the complex frequency-domain expression for the track circuit receiver voltage. Furthermore, a numerical time-domain solution is obtained by applying Fourier transform in conjunction with the Q-D algorithm. Finally, a simulation analysis is conducted to evaluate the receiver’ response under various signal source excitations, comparing the fault and normal conditions of the track circuit tuning section. The results indicate that, under Various Signal Sources excitation, the receiver’ response during a poor contact fault between the tuning unit and the steel rail is more readily distinguishable from other fault types. This approach provides a novel methodology for fault diagnosis in frequency-shifted track circuit tuning sections.

To mitigate galloping in the positive feeder of the catenary system along the Lanzhou - Urumqi high-speed railway in gale zones, a new type of low-wind-pressure positive feeder was developed. By building a CFD (Computational Fluid Dynamics) simulation model, the flow field around the low-windpressure positive feeder was calculated. The study results indicate that the surface grooves on the low-wind-pressure positive feeder can significantly alter the flow field characteristics around the conductor. Additionally, small vortices generated within these grooves produce frictional resistance aligned with the direction of the airflow, while also enhancing momentum exchange with the boundary layer. This dual mechanism effectively delays boundary layer separation and reduces the recirculation zone. The leeward side of the conductor exhibits smaller low-pressure areas and higher pressure levels, thereby significantly reducing aerodynamic drag. Consequently, the drag coefficient of the low-wind-pressure positive feeder is greatly reduced. When the surface structure parameters of the conductor are $\theta=30^{\circ}$ and $R=11 \text{mm}$, the drag coefficient is reduced by 16.42%, and both lateral and vertical displacements are significantly decreased. This solution does not require additional installation equipment nor does it impose extra mechanical load on the catenary system, providing a more effective method for addressing the galloping problem of catenary positive feeders in gale zone.

The purpose of this study is to analyze the galloping characteristics of the catenary positive feeder in fluctuating wind areas considering dynamic-wind angle of attack and aerodynamic damping.Firstly,the flow field model of the catenary positive feeder was established,the fluctuating wind field was simulated by Davenport wind power spectrum and linear filtering method,and the wind speed at inlet in calculation domain was controlled by editing the profile file to simulate and calculate the aerodynamic characteristics of the positive feeder in the fluctuating wind area.Then,taking the positive feeder as the research object,the mathematical model of actual structure and the corresponding finite element model were established.By applying the wind load to the finite element model,the influence of aerodynamic damping caused by the self-movement of the positive feeder on the galloping response was analyzed,and the frequency domain characteristics of galloping displacement of the positive feeder considering aerodynamic damping were studied.Finally,the calculation method of aerodynamic damping by the Guidelines for Electrical Transmission Line Structural Loading(ASCE No.74)was used for the galloping response of the positive feeder and compared with the proposed method.The results show that when considering aerodynamic damping,the galloping amplitude of the positive feeder decreases significantly,and the first-order resonance effect on the vertical displacement and horizontal displacement decreases significantly.The galloping trajectories calculated by the two methods are consistent.Therefore,this study is of great significance to further clarify the ice-free galloping mechanism of the catenary positive feeder in violent wind areas.

China’s rail transit system is developing rapidly, but achieving seamless high-precision localization of trains throughout the entire route in closed environments such as tunnels and culverts still faces significant challenges. Traditional localization technologies cannot meet current demands, and the present paper proposes an autonomous localization method for trains based on pulse observation in a tunnel environment. First, the Letts criterion is used to eliminate abnormal gyro data, the CEEMDAN method is employed for signal decomposition, and the decomposed signals are classified using the continuous mean square error and norm method. Noise reduction is performed using forward linear filtering and dynamic threshold filtering, respectively, maximizing the retention of its effective signal components. A SINS/OD integrated localization model is established, and an observation equation is constructed based on velocity matching, resulting in an 18-dimensional complex state space model. Finally, the EM algorithm is used to address Non-Line-Of-Sight and multipath effect errors. The optimized model is then applied in the Kalman filter to better adapt to the system’s observation conditions. By dynamically adjusting the noise covariance, the localization system can continue to maintain continuous high-precision position information output in a tunnel environment.

To analyze the influence of subgrade form on the aerodynamic characteristics of the overhead contact system (OCS) positive feeder in the gale area of the Lanzhou–Urumqi high-speed railway, based on the aerodynamic theory, the flow field calculation model of the OCS positive feeder under different embankment forms is established, and the aerodynamic characteristics of the OCS positive feeder under various embankment forms are simulated and analyzed. The research shows that the embankment height significantly influences the aerodynamic characteristics of the OCS positive feeder. The aerodynamic coefficient of the positive feeder with an 8 m embankment height is 1.3 times that of the 4 m embankment height. The higher the embankment height, the greater the influence on the aerodynamic characteristics of the positive feeder. When the embankment slope rate is 1:1.5, the aerodynamic coefficient of the positive feeder is smaller than that of other slope rates. In the bridge structure, when the windshield height is greater than 4 m, the aerodynamic coefficient of the positive feeder rises obviously. Therefore, when the windshield is set, the height of the windshield is not too high. The research results can further clarify the mechanism of the OCS positive feeder galloping of the Lanzhou–Urumqi high-speed railway and provide a theoretical basis for the prevention and control of OCS positive feeder galloping, as well as the construction of railway windproof engineering.

To effectively suppress the violent galloping of the catenary additional wires in the strong wind section of high-speed railways, the anti-galloping effectiveness and anti-galloping mechanism of the spacer installed on the catenary additional wires are studied. Firstly, the finite element model of the additional wires of the catenary before and after the installation of the spacer is established. Secondly, the random wind field at the additional wires is simulated by the harmonic synthesis method (WAWS). Finally, the galloping response of the additional wires before and after the installation of the spacer is studied by using the finite element software. The results show that the installation of a single spacer at the midpoint of the span can reduce the vertical amplitude of the AF (Additional Feeder) and the PW (Protection Wire) by more than 39.80% and 41.51%, respectively, and the lateral amplitude decreases by more than 16.55% and 38.30%, respectively. The tension of the AF is greatly reduced, while the tension of the PW is slightly increased, so that the galloping of the AF and the PW tends to be synchronized. With the increase in the number of spacers installed, the anti-galloping effect continues to increase. At the same time, the anti-galloping mechanism of the spacer rod to suppress the vibration of the additional wires through the traction effect is clarified, and the effectiveness of the spacer rod in the anti-galloping of the additional wires of the catenary is proved.

Ensuring railway safety is a top priority, with a central focus on preventing accidents. By thoroughly analyzing data from railway accident investigations, we can pinpoint factors and patterns associated with different types of railway accidents. This proactive approach not only helps reduce the frequency of such incidents but also significantly boosts overall railway transportation safety. This paper investigates the impact of various risk factors on railway safety through the analysis of railway accidents by using data-driven Bayesian networks. First, key data representing the frequency of risk factors directly derived from railway accident reports are collected and analyzed. Then, the risk factors are incorporated into causal analysis for different types of railway accidents. Finally, a historical data-driven approach is utilized to model and gain new insights into the key risk factors causing different types of railway accidents. Meanwhile, a Tree-Augmented Naive Bayes (TAN) is employed to construct a model of interdependencies among risk factors, and the model is validated through sensitivity analysis and past accident records. The research findings demonstrate that the crucial risk factors for all types of accidents include undetected track damage, train operator skills, load, braking system conditions, train speed, traction system failures, level crossings, and bridge damage. Additionally, the research results highlight the differential impact of key factors on different types of accidents, providing a most probable explanation for observing the most likely configurations in the model for a specific scenario. This work contributes to accident prevention and safety decision-making.

The stability of each train, high control accuracy, and minimum safe separation distance are important indexes to measure the performance of the cooperative control system of multiple trains. In this article, aiming at the problem of low accuracy of multiple trains cooperative control with nonlinear running resistance and external disturbance, the distributed cooperative robust adaptive control scheme for multiple trains with RBFNN position output constraints based on train running curve tracking is proposed. Multiple different control techniques are offered for different trains, and that they are based on local knowledge of position, speed, and acceleration. The leading train's speed and position precisely match the planned operation curve, while the following train keeps the tracking interval at the minimum safe distance between two trains. In order to reduce the influence of the uncertainty of basic resistance parameters and external interference on the cooperative control of multiple trains, the parameter uncertainties are compensated by adding a robust adaptive law to the multiple trains control based on position output constraints. The lumped exogenous disturbances (additional resistance, external interference, measurement noise, etc.) are estimated using an RBFNN approximator for the unknown term of the cooperative system. The stability of the cooperative operation of multiple trains is confirmed using the Lyapunov stability theorem. The performance of the proposed scheme was evaluated by the cooperative control system of multiple trains in predecessor following (PF) and bidirectional control (BC) modes.

When the wheel leaves the insulated rail joint (IRJ) at the return current cut-off point, transient overvoltage will generate, causing arcing and burning the IRJ. Based on the basic principle of electromagnetic wave transmission, the characteristic impedance of rail line of ZPW-2000 track circuit under the effect of traction return current impact was analyzed, and the transient overvoltage was obtained. ATP-EMTP was used to model the equivalent circuit of traction return current flowing through the IRJ. The effects of compensation capacitance, wheel-rail contact resistance, rail to earth leakage, earth resistivity, and traction current phase on transient overvoltage were analyzed. Finally, the transient analysis of the two choke transformers connected through the return matching device at the return cut-off point was carried out, and protective measures to suppress the transient overvoltage were proposed. Results show that for the ZPW-2000 track circuit in the station, a inrush current and a transient overvoltage with amplitude up to 46.234kV will also be generated when the train leaves the IRJ. Although the compensation capacitance changed the characteristic impedance of the track circuit, it has no effect on the wave impedance of the rail line under the action of the inrush current and the transient overvoltage. The peak transient overvoltage was reduced by about 92.24% when the traction current phase is 90 degrees and 270 degrees. When the two choke transformers neutrals are connected through the return matching device, the transient overvoltage is reduced by about 90%, which had a very good overvoltage suppression effect.

In order to meet the needs of railway electrical departments for “state repair” of track circuit compensation capacitors and timely and effective monitoring of compensation capacitor status, this paper proposes a new method that combines the feature quantities decomposed from CEEMD and LMD algorithms and utilizes support vector machines for compensation capacitor status monitoring. Firstly, a ZPW-2000A track circuit model is established using KCL, KVL, and transmission line theory. By changing the capacitance value of the compensation capacitor, the shunt current curves of the compensation capacitor in each state are simulated. Then, the shunt current curves are decomposed into each order component using CEEMD and LMD, and fuzzy entropy is calculated and combined into a new feature vector. Finally, it is input into a trained multi-class SVM model for state monitoring. The experimental results show that the accuracy of compensating capacitor state monitoring is improved to 91

Railway signals’ fault text data contain a substantial amount of expert maintenance experience. Extracting valuable information from these fault text data can enhance the efficiency of fault diagnosis for signal equipment, thereby contributing to the advancement of intelligent railway operations and maintenance technology. Considering that the characteristics of different signal equipment in actual operation can easily lead to a lack of fault data, a fault diagnosis method for railway signal equipment based on data augmentation and an improved attention mechanism (DEIAM) is proposed in this paper. Firstly, the original fault dataset is preprocessed based on data augmentation technology and retained noun and verb operations. Then, the neural network is constructed by integrating a bidirectional long short-term memory (BiLSTM) model with an attention mechanism and a convolutional neural network (CNN) model enhanced with a channel attention mechanism. The DEIAM method can more effectively capture the important text features and sequence features in fault text data, thereby facilitating the diagnosis and classification of such data. Consequently, it enhances onsite fault maintenance experience by providing more precise insights. An empirical study was conducted on a 10-year fault dataset of signal equipment produced by a railway bureau. The experimental results demonstrate that in comparison with the benchmark model, the DEIAM model exhibits enhanced performance in terms of accuracy, precision, recall, and F1.

Insulated rail joint (IRJ) as one of the components of the track circuit will be burned once the electric arc is generated when the train wheel passes through the insulated rail joint and the track circuit occurs the red-light band fault, which has a great impact on the safety of the train. Reducing the voltage at both ends of the insulated rail joint can effectively prevent the occurrence of electric arc. Clarifying the wheel-IRJ contact resistance is the basis for analyzing the voltage of wheel-IRJ. The effective apparent contact area of the wheel-IRJ contact was derived through the mathematical relation. Considering the surface roughness parameters, based on the electrical contact theory and the Greenwood-Williamson (GW) model, the mathematical models of the wheel-IRJ contact resistance and current density were established, and their influencing factors were analyzed. The results show that the contact resistance increased first and then decreased. The influences of load, roughness of the contact interface, and electric arc heat on the contact resistance were greater. Considering the influencing factors of contact resistance and current density, corresponding protective measures were proposed to reduce the potential difference at both ends of the insulated rail joint.

Icing galloping of overhead conductors will lead to wire breakage, fittings wear, and even tower collapse accidents, which may lead to large-scale power outages. In order to study the galloping law of conductors with different icing forms, this paper takes the 110 kV transmission line of Liannan line as the research object. Based on the aerodynamic theory, the analysis model of wind-induced vibration response of conductors with different icing forms is established. The time history analysis of each iced conductor model was carried out by fluid-solid coupling method. The results show that the most galloping wind attack angles of crescent, fan and D-shaped iced conductors are around 20 °, 160 ° and 60 °, respectively. With the increase of icing thickness, the galloping velocity of the conductor decreases significantly. Under the same conditions, the galloping amplitude of crescent-shaped iced conductor is the largest, followed by fan-shaped, and D-shaped is the smallest. When the velocity is small, the galloping amplitude of the conductor increases with the increase of velocity. When the velocity reaches a certain value, the galloping amplitude of the wire decreases with the increase of the velocity. The research results can provide an important reference for the study of icing galloping law of overhead conductors.

To clarify the influence mechanism of windbreak wall wake on the galloping of catenary positive feeder， taking the positive feeder of Lanzhou-Urumqi high speed railway as the research object， based on the aerodynamic theory， the analysis model of wind-induced vibration response of positive feeder is established. The Fluid-Structure Interaction method is used to analyze the time history of two-dimensional models with different degrees of freedom and frequency ratio. The results show that the degree of freedom and frequency ratio have a great influence on the galloping amplitude of the positive feeder. The smaller the frequency ratio， the greater influence of wind speed on the amplitude of the positive feeder， and the larger the wind speed range when the positive feeder gallops. The galloping amplitude of the positive feeder in the vertical single degree of freedom system is greater than that in the vertical horizontal two degree of freedom system， indicating that the horizontal vibration of the positive feeder has a certain limiting effect on the vertical vibration. When the positive feeder vibrates in the wake of windbreak wall， the windward angle of the positive feeder changes constantly. When the windward angle is large， which is easy to induce a large galloping of the positive feeder. The galloping mode of the positive feeder of the catenary in the strong wind section is determined as Den. Hartog galloping without icing. The research results further clarify the galloping mechanism of the positive feeder under the condition without icing in the strong wind section， and provide a certain theoretical support for the prevention and control of the galloping of the positive feeder of the catenary.

为抑制兰新高铁大风区正馈线舞动,保证列车安全运行,首先,设计新型低风压正馈线,仿真获取常规正馈线和低风压正馈线在不同风载荷下的气动力参数和舞动幅值,并进行对比分析;其次,对防舞效果较佳的 3种低风压正馈线建立三维有限元模型,并施加拉伸载荷,模拟正馈线舞动时的受力情况;最后,分析低风压正馈线形变及应力变化.结果表明:低风压正馈线自由端形变量远大于固定端,铝股线形变量大于钢股线,且越往外层,股线形变量越大;在绞线制造时可以考虑将钢层和铝层交替绞合,以平衡绞线的导电性和刚性.在股线相互接触的位置出现了应力集中,应力集中位置与股线绞合方向相同;在绞线制造时,可以考虑在股线表面覆缓冲层,以减缓正馈线舞动时股线之间的振荡冲击,并延长正馈线的使用寿命;低风压正馈线模型的凹槽小圆弧半径与常规正馈线半径的比值越大,最外层铝股线的形变越大,正馈线舞动时越容易断股;在低风压正馈线选型时应该综合考虑,平衡防舞有效性与使用寿命.

为抑制大风环境下兰新高铁接触网正馈线强烈舞动及线间放电现象,基于接触网结构和正馈线舞动特点提出一种新型绝缘防舞装置,其绝缘保护套可提高线间绝缘裕度,扰流段可改变导线整体气动特性.通过仿真分析了不同风速下安装防舞装置前后正馈线气动特性和舞动响应,研究不同覆盖率、扰流段高度和绝缘保护套厚度参数影响下装置的防舞效果,最后分析了新型绝缘防舞装置的电场特性.结果表明:安装新型绝缘防舞装置可以抑制导线舞动且防舞装置覆盖率越高,防舞效果越显著.安装四段防舞装置后导线垂向和横向舞动幅值最高分别下降57.76%和54.68%.装置的扰流段高度为75%绝缘保护套外径且护套厚度为3 mm时防舞效果更明显.装置安装后正馈线表面最高场强下降52.96%,距正馈线4 mm圆周平均场强下降36.71%.研究成果可为兰新高铁大风区段接触网正馈线及其他架空输电导线舞动提供合理有效的防舞方案.

Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena, namely, the high -amplitude, low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensu-ing effect that wind can have on these. In this work, the galloping time history of a wire with distorted (fixed in time) shape due to the formation of ice is analyzed numerically in the frame of a fluid-solid coupling method for different wind speeds and levels of turbulence. The results show that the turbulence intensity has a moderate effect on the increase of the conductor's aerodynamic lift and drag coefficients due to ice accretion; nevertheless, the corresponding changes in the torsion coefficient are very significant and complicated. A high turbulence intensity can affect the torsion coefficient in a certain range of attack angles and increase the torsion angle of the conductor. Through comparison of the galloping phenomena for different wind velocities, it is found that the related amplitude grows significantly with an increase of the wind speed. For a relatively large wind speed, the galloping amplitude is more sensitive to the turbulence intensity. Moreover, the larger the turbulence intensity, the larger the conductor's vertical and horizontal galloping amplitudes after icing. The torsion angle also increases with an increase in the wind speed and turbulence intensity.

针对复杂系统的多维修人员定期检修策略,考虑维修人员数量对系统维修成本及停机时间的影响,提出一种两层嵌套粒子群结构的复杂系统多目标维修决策优化方法.该方法利用底层粒子群算法求解维修任务排序的并行调度问题,得出检修节点的最小化最大维修时间,再通过顶层多目标粒子群算法,对系统可靠度、可用度及维修成本模型进行搜索优化,得到该三目标模型的Pareto前沿解集,并分析前沿粒子在三个目标的平衡关系,推荐出最优的维修方案,通过算例验证了该方法的可行性.所提方法在有效地提高系统可靠度和可用度、降低维修成本的同时,还可以为决策者对组件维修等级的确定、维修人员任务的分配等问题提供决策支持.

In response to the frequent failures of turnout machines, which make it difficult for on-site staff to predict these failures, this paper proposes a method for predicting the performance degradation trend of turnout machines based on Autoencoder (AE) and Temporal Convolutional Network (TCN). First, time-domain, frequency-domain, and time-frequency features of the turnout machine's action power data are extracted to construct a feature vector set that reflects the degradation process of the turnout machine. KPCA is utilized to remove redundant information present in multiple-domain features. A Healthy Indicator (HI) is constructed based on the AE network. Subsequently, a performance degradation prediction model based on TCN is built to achieve the prediction of the turnout machine's degradation trend. The effectiveness of the method is verified using on-site datasets. The outcomes demonstrate that KPCA successfully reduces the feature set from 22 dimensions to 2 dimensions, retaining 81.33% of the information from the original optimal feature set. Additionally, the approach of constructing a healthy indicator based on the AE network proves to be effective. The generated healthy indicator accurately reflects the degradation process of the turnout machine's performance over time. The model developed using the TCN algorithm accurately forecasts the performance degradation of the turnout machine. This model outperforms prediction models constructed based on LSTM networks and GRU networks in terms of prediction accuracy. This method is generally applicable and has practical guidance for on-site maintenance.

电弧高温是机械绝缘节(简称"绝缘节")烧损碳化导致其无法满足轨道电路绝缘要求的主要原因.基于磁流体动力学理论,考虑电磁场、热场、流场以及电弧物性参数的影响,在COMSOL软件中建立绝缘节电弧的多物理场耦合模型;通过仿真求解不同电弧作用次数、电弧电流以及电弧移动速度下的电弧温度分布,分析绝缘节碳化规律与钢轨温升规律.结果表明:在较低电弧电流下,随着电弧作用次数的增加,绝缘节温度升高、碳化程度加剧,钢轨表面温升则不明显,绝缘节在电弧作用1～2次时未出现碳化,作用3次时出现碳化且碳化率为15.2％,作用6次时碳化率升至69.4％,而钢轨表面温度在电弧作用6次时仅升高142.2K;电弧电流越大,绝缘节发生碳化的程度也越高,钢轨表面温度也随之升高,绝缘节在电弧电流为40～60 A时未出现碳化,80 A时出现碳化且碳化率为33.5％,电弧电流大于等于120 A时碳化率升至100％,而钢轨表面温度在电弧电流由40 A增至180 A时升高440.8 K;电弧移动速度越快,电弧对绝缘节和钢轨的传热影响越小,越有利于降低绝缘节的碳化,电弧移动速度从10m·s-1增至20 m·s-1时,绝缘节碳化率降低16.7％,钢轨表面温度降低116 K.