Search Results (114)

The last years have seen the increasing development of innovative railway pantographs based on smart materials and equipped with monitoring features based on wireless sensor nodes. In this scenario, one of the most important challenges is the power supply of pantograph sensors. Energy harvesting systems have been proposed for powering monitoring sensors in a variety of applications, including railway pantographs. These systems convert ambient energy sources into electrical energy. The use of energy harvesting systems coupled with storage devices, such as rechargeable batteries or supercapacitors, can be a very promising solution for making the sensors self-powered, thus avoiding the drawbacks associated with supplying from the main grid or disposable batteries. In this paper, the operating principles of the main technologies used for energy harvesting in railway pantographs are described in detail, together with some examples of laboratory prototypes and commercial devices. The proposed analysis focuses on the perspectives and challenges of various energy harvesting technologies and can help select the most suitable technology for the development of innovative sensorized pantographs. Full article

Under severe ice and snow weather, ice-covered pantograph–catenary arcs affect the safe operation of high-speed trains. This study investigates the impact of ice-covered arc electrical characteristics, plasma parameters, and material ablation mechanisms. By constructing a comprehensive pantograph–catenary icing experimental platform, arc voltage, current signals, high-speed dynamic images, and emission spectra were synchronously collected under different icing thicknesses ranging from 0 to 15 mm. Research indicates that ice coverture causes frequent “extinction–reignition” phenomena during the arc initiation stage due to the latent heat absorbed by melting ice, significantly reducing the initial stability of arc combustion. Spectral analysis confirms that the arc excitation temperature and energy density are positively correlated with the concentration of hydrogen ions produced by water vapor ionization, reaching a peak under the 5 mm icing condition. Experimental results show that the average energy density of ice-covered arcs is approximately double that of the non-iced condition, causing the ablation pits on the carbon strip to exhibit characteristics of greater depth and wider copper deposition zones. This study reveals the unique mechanisms and damage characteristics of icing pantograph–catenary arcs, providing an important basis for the safe design and maintenance of pantograph–catenary systems in high-cold railway environments. Full article

Motivated by altitude-induced fluctuations in oxygen partial pressure (pO₂) and their impacts on PCS off-line arc motion and erosion response, this study proposes a comparative experimental approach featuring single-variable control under constant total pressure and coordinated multi-source electrical-signal observation. A reciprocating current-carrying arc-generation rig was established, in which pO₂ was equivalently regulated via a constant-pressure gas substitution and mixing approach. High-speed imaging–based quantitative vision analysis was integrated with synchronized voltage–current measurements to evaluate the net effects of five O₂ volumetric fraction levels (6, 11, 14, 17, and 21 vol%) under a DC supply of 120 V/25 A on arc dynamics, electrochemical processes, and contact pair erosion. Based on repeated-test results, the 14 vol% case exhibited the poorest stability (maximum fluctuation coefficient 20.306%), whereas the 17 vol% case showed the lowest current-carrying efficiency (minimum 56.070%) together with the most severe erosion damage. Moreover, with increasing pO₂, the erosion morphology evolved in a staged manner, transitioning from localized central ablation accompanied by melt-related traces to adhesive wear-induced delamination, and ultimately to electrochemical oxidative wear. Overall, pO₂ imposes a pronounced non-monotonic “window effect” on arc stability and erosion, providing key evidence for PCS structural optimization and risk assessment in open operating environments. Full article

This paper investigates a class of coupled $\psi$-Hilfer fractional pantograph–Langevin equations with nonlocal integral boundary conditions. By reformulating the problem as an equivalent fixed point equation and employing Mönch’s fixed point theorem together with the Kuratowski measure of noncompactness, we establish sufficient conditions for the existence of at least one solution. Under additional Lipschitz-type assumptions, we prove Ulam–Hyers stability on a suitable closed ball and derive explicit, computable stability constants. A concrete numerical example is presented in which all hypotheses are verified and the stability constants are explicitly computed (e.g., $K_1\approx 3.811$, $K_2\approx 2.761$), illustrating the applicability of the theoretical results. The study contributes additional qualitative results to the analysis of fractional pantograph–Langevin systems within the unified framework of $\psi$-Hilfer fractional derivatives. Full article

As well as the off-line phenomenon between the pantograph strip and the contact wire that occurs frequently, the current collection quality of trains is potential under threat. Pantograph arcing can bring about overvoltage and harmonics in the traction circuit, which can seriously threaten the construction’s strength and efficiency of current collection. Meanwhile, the electrified railway might meet very complex environments, including the various routes under different air pressures. When the train runs in a medium- or low-pressure area, the reduction in air pressure may result in significant differences in the dynamic evolution characteristics of pantograph arcing. So it is necessary to carry out a detailed study on the influence of pantograph arcing on the current collection of electrified trains in a low-pressure environment. In this paper, we proposed an improved pantograph arcing model suitable for medium-to-low-pressure regions, with the pressure parameters taken into consideration. Furthermore, we examined the influence of pantograph arcing under medium-to-low-pressure environments on the traction power supply system. The arcing dynamics, including the arc duration, the current zero-crossing, and the arcing-released energy at different air pressures were compared. The overvoltage and the harmonic distribution of the traction drive system were also analyzed. This work may be helpful for the design and maintenance of electrified railways under medium-to-low-pressure environments. Full article

The regularity of the catenary system and the stability of pantograph–catenary interaction are crucial for ensuring continuous and stable current collection quality in high-speed trains. Given that the dropper is a key suspension component within the catenary, the state of service integrity directly determines the regularity of, and dynamics within, the pantograph–catenary system. However, under long-term alternating loads and environmental influences, the dropper inevitably suffers damage due to strand fracture. The geometric regularity of the catenary is consequently disrupted, and the current collection quality of trains can deteriorate. While substantial efforts have been devoted to the study of pantograph–catenary dynamics under ideal or intact dropper conditions, research on current collection quality when the dropper has different types of damage remains insufficiently understood. This study focuses on the practical operational situation of high-speed railways, investigating the impact of dropper damage on current collection quality. Firstly, based on the pantograph–catenary parameters of an actual line, a dynamic model capable of simulating different types of dropper damage was built. Secondly, the current contact quality under various types of damage was explored in detail by several time-domain statistical features. Finally, within the typical speed range of 250 km/h to 350 km/h, the evolution of pantograph–catenary dynamic behavior under the combined effects of operating speed and dropper damage was analyzed, providing a theoretical basis for the reliable assessment of pantograph–catenary current collection quality and the formulation of stable operation and maintenance strategies. Full article

Sliding contact wear at the pantograph–catenary interface directly impacts the current collection performance and power supply reliability of electrified railways. Addressing the challenges in multi-environmental wear studies—namely, fragmented modeling chains, inconsistent parameter calibrations, and prohibitive computational costs that hinder horizontal comparisons—this study develops an equivalent parameterized modeling framework tailored for engineering assessment. The framework encapsulates environmental effects as equivalent load increments and interface coefficient corrections, facilitating efficient multi-scenario parameter scanning within a 3D contact model. Findings reveal that environmental factors drive wear through a distinct “pressure-wear” nonlinear decoupling mechanism. In sandy environments, abrasive-mediated micro-cutting dominates, leading to a monotonic surge in wear depth as sand concentration increases, despite a buffered contact pressure response. In icing conditions, the synergy of low-temperature brittleness and geometric impact renders hotspot wear highly sensitive to temperature fluctuations. For salt spray conditions, the environmental impact is represented via equivalent corrections to the interfacial parameters; within this equivalent framework, the results suggest that salt spray intensity has a more pronounced effect on wear accumulation than humidity alone. This work reveals the divergence of dominant damage pathways across environments, offering a quantitative basis for the differentiated maintenance and remaining life estimation of pantograph–catenary systems in extreme climates. Full article

With the rapid development of high-speed railways, the dynamic performance of the pantograph–catenary system plays a crucial role in ensuring the safe and stable operation of trains. This study investigates the effect of the structural parameters of the pantograph–catenary system to achieve good dynamic interaction performance under high-speed conditions. A finite element model of the catenary system, incorporating nonlinear cable and truss elements, and a lumped mass model of the pantograph are developed. The penalty function method is employed to simulate the pantograph–catenary interaction. A total of 2187 dynamic simulations are performed, with seven variables—pantograph parameters, span length, contact wire tension, messenger wire tension, number of droppers, stitch wire length, and stitch wire tension. The comprehensive effect of these parameters is evaluated based on dynamic performance indicators, such as pantograph–catenary contact force, pantograph head lift, and support point lift. The results indicate that increasing the number of droppers, contact wire tension, and messenger wire tension enhances dynamic performance, while an increase in span length negatively affects performance. Stitch wire tension has little to no effect. Full article

The pantograph slider is a key friction component in high-speed train systems, and its performance directly affects the safety and efficiency of operation. In this study, Cf/C/CuNi composites with carbon fiber contents of 1 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% were prepared by a solvothermal method combined with spark plasma sintering (SPS). The influence of carbon fiber content on the mechanical and friction properties of the composites was systematically studied. The results show that the flexural strength of the composites increases from 20.20 MPa to 38.45 MPa with an increase in the carbon fiber content. However, excessive carbon fiber content can lead to fiber agglomeration and interface defects, thereby reducing the friction stability and increasing the wear rate from 0.64 g/m³ to 1.60 g/m³. A carbon fiber content of 1 wt.% helps to form a continuous lubricating film, resulting in a low and stable friction coefficient. This study provides valuable insights for the design and optimization of high-performance pantograph slider materials for high-speed railway applications. Full article

The pantograph–catenary system is a critical component of the traction power supply network. Due to hard points on the overhead contact line and vibrations of the pantograph, pantograph–catenary separation may occur, leading to offline DC arc events. To investigate the characteristics of DC arcs generated during pantograph–catenary separation in metro systems, this study constructs a laboratory platform that simulates the offline process and analyzes the electrical characteristics, optical intensity, and arc-burn duration under different electrode separation conditions. First, a DC pantograph–catenary offline arc simulation platform is developed using a contact wire, a carbon-strip pantograph slider, and a linear motor, enabling slider movement in both horizontal and vertical directions. Second, offline discharge experiments are conducted to compare the discharge process and electrical arc characteristics with and without horizontal slider motion. Finally, arc luminosity and burn duration are measured under various electrode separation configurations, and the influence of voltage level, current level, and electrode material is examined. Experimental results reveal a significant polarity effect, where the arc burn duration is notably longer when the contact wire serves as the cathode than when the carbon slider serves as the cathode. At the instant of separation, the high electric field intensity within the micro-gap triggers pronounced “peak phenomena” in both arc resistance and power, accompanied by abrupt voltage surges and transient current dips. Furthermore, the introduction of horizontal motion modulates the arcing process, causing the stable arcing voltage to follow a distinctive trend of a slow increase followed by a gradual decrease, which differs from static separation characteristics. Finally, this study demonstrates that voltage levels exert a more dominant influence on arc luminosity and duration than current levels, while the maintenance voltage of the arc channel remains significantly lower than the air breakdown voltage. Full article

Transient arcing often occurs as an electric locomotive traverses an electrical sectioning overlap (ESO), deteriorating current collection stability and reducing the durability of the pantograph–catenary (PC) system. In this study, the formation mechanism and electrical evolution characteristics of transient arcing in the ESO region are investigated through theoretical analysis and numerical simulations. First, based on the dynamic motion of the locomotive passing through the ESO, the transient arcing mechanism of the ESO is clarified, and the plasma characteristics of the arc are described. Then, the electromagnetic, airflow, and thermal field interactions within the PC contact gap during arc ignition are analyzed. A Multiphysics coupled PC arc model is developed, incorporating aerodynamic, electromagnetic, and heat transfer effects. Subsequently, finite element meshing and boundary conditions are applied to simulate the transient evolution of the ESO arc. Finally, the transient arcing characteristics of the ESO are analyzed. The results indicate that the current density is highly concentrated at the initial arcing stage and gradually forms an axially symmetric conductive channel (approximately 10⁷ A/m²), which shifts upward as the contact gap increases. Moreover, due to the geometric discontinuity of the ESO, a strong localized electric field develops near the wire edge, leading to arc root migration and reignition. Full article

The article presents a comprehensive determination and analysis of the dynamic accuracy of the AC traction network–pantograph interface using an equivalent lumped-parameter RLC model derived from a distributed-parameter representation of the traction line. The study investigates the system’s response to representative excitation signals: step, sinusoidal, and multi-harmonic, where the root mean square value of the voltage error at the network–pantograph interface is adopted as the main performance indicator. A novel contribution of this work lies in determining the upper bound on the dynamic error (UBDE) for input signals constrained by realistic physical limitations: initially by magnitude and duration, and subsequently extended with an additional rate of change constraint. In the first case, an iterative optimization procedure is applied to determine the constrained excitation and its corresponding error, while in the extended case, the problem of maximizing the dynamic error energy is solved numerically using a genetic algorithm. In both formulations, the objective is to identify extreme, physically admissible excitation waveforms that represent the most unfavorable dynamic scenarios for voltage reproduction within the traction network–pantograph RLC interface. The results obtained in this study are of both theoretical and practical significance. They allow the identification of frequency ranges and resonance conditions that intensify dynamic errors, support the design of compensation and filtering strategies, and enable the assessment of the system robustness to fast disturbances and supply voltage distortions. From a theoretical point of view, the article introduces a unified methodology for the determination and evaluation of dynamic errors and their worst-case upper estimates under realistic signal constraints, providing a foundation for future research on control design, optimization, and voltage quality requirements in AC traction power systems. Full article

Overhead Rigid Conductor Systems (ORCS) are widely used in modern urban rail networks, where precise monitoring of contact wire geometry is critical for safe operation. Traditionally, these critical parameters have been primarily obtained through expensive and environmentally sensitive industrial camera systems, presenting significant limitations. This work presents a novel framework for predicting dynamic stagger and localizating section overlaps within ORCS, offering a more cost-effective and robust alternative. The methodology integrates three components: a beam-based model to obtain dynamic stagger under moving-load conditions, a difference matrix representation with kurtosis-guided lag selection and prominence-informed peak detection for overlap localization, and zero-phase Butterworth filtering to suppress dynamic pulsations. The framework was validated on 32 distinct overlap segments across both triangular and sinusoidal ORCS geometries. The section overlap classifier achieved an $F_{\beta }$-score of 1 for both layout types, indicating 100% identification of overlaps. Furthermore, the framework exhibits excellent prediction of the stagger probability distribution, with Bhattacharyya distances between measured and predicted distributions of 0.0115 for triangular layouts and 0.0517 for sinusoidal layouts. The section-wise mean Bhattacharyya distance was validated as 0.0734, and the framework maintained robustness across ±10% speed fluctuations. This research provides a reliable, robust, and economically viable method for ORCS dynamic stagger monitoring. Full article

Most electrified railway networks are powered through a pantograph–overhead contact line (OCL) interface to ensure safe and reliable operation. The OCL is one of the most vulnerable components of the train traction power system as it is subjected to multiple impacts from the pantographs and to unpredictable environmental conditions. Wear, mounting imperfections, contact incidents, weather conditions, and inadequate maintenance lead to increased degradation of the pantograph–OCL current collection performance, causing degradation on contacting elements and assets failure. Incidents involving the pantograph–OCL system are significant sources of traffic disruption and train delays, e.g., Network Rail statistics show that, on average, delays due to OCL failures are 2500 h per year. In recent years, maintenance strategies have evolved significantly with improvements in technology and the increased interest in using real-time and historical data in decision support. This has led to an expansion in sensing systems for structures, vehicles, and machinery. The railway industry is currently investing in condition monitoring (CM) technologies in order to achieve lower failure rates and increase the availability, reliability, and safety of the railway service. This work presents a comprehensive review of the current CM systems for the pantograph–OCL, including their advantages and disadvantages, and outlines future trends in this area. Full article

The ablation of pantograph sliders caused by pantograph–catenary arcing is a critical issue in the operation of pantograph–catenary systems. The arc discharge induces localized high temperatures that lead to the melting and even evaporation of the slider material, resulting in material loss. This phenomenon directly impacts the power supply safety and economic efficiency of trains. This study establishes a mathematical model of pantograph–catenary arcing based on Magneto Hydro Dynamics (MHD) theory, incorporating the physical parameters of the arc as well as electromagnetic, thermal, and radiative phenomena. Through secondary development using COMSOL 6.2 finite element software, the temperature distribution within the arc column region and on the surfaces of the electrode plates in pantograph–catenary arcing was simulated. The effects of the pantograph–catenary gap and slider material on arc ablation were investigated. The results show that with the increase in the distance between the pantograph and catenary, the arc shape lengthens gradually, and the high-temperature area inside the slider material shrinks gradually. When the arc duration is constant, the copper-impregnated carbon slider exhibits the best ablation resistance. Increasing the sublimation latent heat of the slider material enhances its anti-ablation performance. The findings of this study provide a valuable reference for understanding and mitigating surface arc erosion in pantograph–catenary systems. Full article