Search Results (1,020)

Wind-blown sand threatens railway safety in arid regions. Existing measures mainly protect the windward side and cannot fully prevent particles from crossing the embankment. These particles can be re-entrained by leeward flows and redeposited on the track. This study combines wind tunnel experiments, large eddy simulation, and field observations to examine leeward-side protection for a high railway embankment. Three configurations are tested: no protection, baffles on the leeward slope, and a checkerboard barrier at the slope toe. The results show clear differences in flow structure and sand transport. Without protection, flow reattaches within 2–3 H (H is the height of the embankment) and near-surface velocity reaches 10–11 m/s. With baffles, reattachment shifts to 3–4 H and velocity decreases to 7–9 m/s. With a checkerboard barrier, reattachment is delayed to 4–5 H and velocity reduces to 4–6 m/s, forming a stable low-velocity zone. Surface shear stress decreases from 0.4–0.5 Pa to 0–0.2 Pa, and particle concentration near the shoulder drops by about one order of magnitude. Particle transport is weakened and deposition concentrates at the slope toe. Subgrade sand accumulation decreases from 350–480 g/min to 170–250 g/min. Field results confirm these trends. The checkerboard barrier effectively limits sand movement and improves deposition stability. The proposed leeward-side protection measures can effectively reduce sand accumulation on railway infrastructure, thereby improving the long-term operational safety, resilience, and sustainability of railways in desert environments under increasing wind–sand hazards. Full article

With the integrated development of high-speed railways and urban underground rail transit, large high-speed railway station buildings are often seamlessly connected or even co-constructed with subway structures, forming a complex structural system that integrates high-speed rail, subway, and station buildings. To investigate the dynamic performance of such “ integrated station-bridge” station buildings constructed with subways, this paper takes Yichang North Station as an engineering case study and examines its vertical dynamic characteristics under multi-source train-induced loads. The station adopts a structural configuration where the station tracks are fully integrated with the station building, while the main lines are separated from it. To accurately simulate the entire process of train operation, this study established a refined “train-track-station” spatially coupled dynamics model that incorporates high-speed and subway trains, tracks, and the station structure. Based on this model, various operational scenarios were systematically analyzed, including high-speed trains passing at different speeds, parallel operation of multiple train lines, and combined operation of high-speed and subway trains. The results demonstrate that, when single or multiple high-speed train lines pass through the station at the design entry speed of 80 km/h, the vertical vibration acceleration of the elevated waiting level meets human comfort standards. The train-induced vibration response is transmitted and superimposed along the “column–beam–slab” path, resulting in localized acceleration peaks at the mid-span regions of beams and slabs directly above the tracks. Second, the impact of subway train operation alone on the vibration of the elevated level is significantly weaker than that of high-speed trains. Furthermore, under combined high-speed and subway train operations, the additional vibration contribution from subway trains shows a decreasing trend as the number of simultaneously operating high-speed train lines increases. The findings of this study validate the effectiveness of the structural design of Yichang North Station in terms of train operational safety and passenger waiting comfort. The revealed patterns of multi-source vibration transmission and superposition can provide important theoretical and numerical references for the dynamic optimization design and vibration control of similar integrated transportation hub structures. Full article

Although rock bolts are widely used in tunnel engineering, their effectiveness remains uncertain under specific geological conditions. This study investigates a single-track railway tunnel excavated in gently dipping stratified mudstone to evaluate the applicability of sidewall rock bolts. Field measurements, including tunnel deformation, initial support reaction, and bolt axial force, were conducted. An equivalent support force of bolts was quantified, and a coupled relationship between bolt axial force and surrounding rock displacement was established based on interfacial mechanics. In addition, a physics-constrained inversion framework was developed to reconstruct the displacement field from measured bolt responses. The results show that tunnel deformation is minimal, with a maximum crown settlement of 4.7 mm and convergence of 3.6 mm. The initial support bears 93.4% of total support capacity, compared with merely 6.6% from rock bolts, revealing that primary support dominates load bearing under small deformation. Further parametric analysis indicates that increasing bolt length beyond 1 m does not further enhance the support performance. These findings suggest that there is potential for optimizing the length of fully grouted sidewall rock bolts in heterogeneous, gently dipping layered mudstone tunnels. Full article

Regulations in Poland require acceptance load tests to verify bridge response under moving loads before structures are approved for operation. These tests are mandatory for new bridges, after major renovations, and for reconstructed structures, and may also be conducted as supplementary assessments of existing bridges to determine their load-carrying capacity. This paper presents one of the first documented applications, to the authors’ knowledge, of low-cost sensing technology for capturing bridge displacements with sub-millimeter tracking precision during acceptance load testing. The study explores the use of modern remote sensing methods based on digital image correlation (DIC) to assess vertical displacements of a truss railway bridge span under moving loads. Video data were recorded using a standard smartphone under nighttime conditions with artificial lighting, demonstrating a highly accessible and cost-effective measurement approach. The collected data were processed using the DES Vision System and compared with results obtained from traditional measurement techniques, such as accelerometers, enabling an evaluation of the accuracy and precision of the DIC method. The findings show that smartphone-based video recordings can provide displacement measurements with millimeter- to sub-millimeter-level tracking precision. Additionally, a numerical finite element method (FEM) model was developed to support interpretation of the structural response under moving loads. Full article

Heavy-haul railways require efficient rail replacement because extreme axle loads and high-density transport accelerate rail wear. Traditional manual-led processes are limited by fragmented operations, high labor demand, and complex equipment scheduling, typically completing about 1 km of rail replacement within a 4 h maintenance window and requiring approximately 340 workers. This study is positioned as construction-process modeling, workflow organization, and simulation-supported feasibility analysis for an integrated rail-changing workflow, rather than the development or field validation of a fully mature rail-changing machine. The proposed workflow coordinates rail unloading, on-board welding, fastener disassembly, rail cutting, exchange-recovery, fastening, closure welding, and final inspection through a highly parallel construction organization. A process-level train-set configuration, including a tractor, a long-rail comprehensive transport vehicle, an exchange-recovery integrated transport vehicle, and a mobile welding vehicle, is used as an engineering carrier to support the closed-loop workflow of unloading, welding, exchange, and recovery. Based on engineering time-study analysis, field experience, expert consultation, and discrete-event simulation, the results indicate that the proposed workflow has the potential to complete a simulated 2 km rail-changing task within a single 4 h maintenance window with an estimated labor demand of 80–95 personnel under the specified assumptions. The study provides conceptual and simulation-supported feasibility evidence for construction-process organization, rather than field-validated machine performance, and offers a technical reference for improving the mechanization and coordination of heavy-haul railway maintenance. Full article

The wheel–rail impact effect is prominent in the low vibration track (LVT) in the curved sections of heavy-haul railways, where fastener failure and the support block hanging void are prone to occurring. To investigate the impact of these issues on the dynamic characteristics of the vehicle–track coupled system, this study establishes a coupled dynamics model of a heavy-haul train and LVT, taking into account the topological relationships of vehicle components, multipoint wheel–rail contact, and track irregularities. Comparative analyses are conducted to evaluate the effects of the location, quantity, and failure degree of fastener failure and support block hanging voids on running safety and stability. The results show that (1) compared to the normal condition, fastener failure and support block hanging voids lead to varying degrees of increases in response indicators, thereby intensifying the wheel–rail impact; (2) bilateral failure exhibits more pronounced dynamic responses than unilateral failure, and when the number of failed fasteners or hanging voids exceeds one, the maximum wheel load reduction rate increases significantly; (3) as the gap of the hanging void increases, the dynamic response also increases, and when the gap reaches approximately 3 mm, the support block can be considered fully suspended; and (4) comprehensive analysis indicates that fastener failure poses a greater threat to running safety than support block hanging voids and thus warrants greater attention in practical engineering applications. This study provides theoretical support for the maintenance and repair of heavy-haul railways. Full article

The railway track system is a complex assembly of rails, sleepers, and fastenings designed to ensure operational stability and safety. Within this framework, rail pads play a critical role in load transfer, vibration attenuation, and noise control. This study provides a comprehensive bibliometric analysis of research on railway components published between 2015 and 2024, based on 288 documents retrieved from Scopus, Elicit, and Web of Science. Publication trends reveal a steady increase in research output over the study period, primarily driven by Spain and China. Keyword co-occurrence analysis yielded 51 keywords organized into seven thematic clusters, with the highest frequency terms being “rail pad”, “noise”, “dynamic property”, and “MTHDRP”. The analysis highlights a significant focus on materials such as TPEs, EPDM, and EVA, with static preload and stiffness identified as the most scrutinized performance factors. Findings indicate a clear thematic shift from traditional field testing toward advanced material science and sensor-integrated monitoring technologies. Ultimately, this review outlines future research trajectories emphasizing sustainability, smart sensor integration, and predictive maintenance. By synthesizing a decade of academic contributions, this study serves as a strategic roadmap for optimizing the long-term durability and efficiency of modern railway infrastructure. Full article

With the rapid expansion of rail transit networks and increasing operational density, foreign object intrusion on tracks has emerged as a critical threat to train safety. Conventional manual inspection methods suffer from low efficiency, high miss rates, and inadequate real-time performance, failing to meet the stringent requirements of modern intelligent railway maintenance. While deep learning offers a promising paradigm shift, existing models often struggle with complex background interference and multi-scale target detection in railway scenarios. To address these challenges, this paper proposes CMF-Net, a unified detection framework for railway track foreign object detection. The CGG module serves as a lightweight feature extraction unit in the backbone, mitigating gradient vanishing and overfitting. The MSAF module enables adaptive multi-scale feature fusion via dual attention (CBAM), enhancing small-object detectability. The FGAF module captures fine-grained edges and textures through a four-branch decomposed convolution and fine-grained attention, suppressing complex background interference. The BiFPN module restructures the neck for efficient bidirectional cross-scale feature fusion. Furthermore, the TPSA module injects explicit railway-domain prior knowledge by fusing a learnable rail-centerline distance-decay field with the CBAM spatial attention map, guiding the detector to focus on operational danger zones and reducing false positives. Experiments on the OFBDs dataset demonstrate that CMF-Net achieves a mean Average Precision (mAP50) of 89.2% and an mAP50:95 of 64.5%, surpassing the baseline YOLOv5s by 4.8 pp and 5.3 pp, respectively. The model maintains a compact parameter size of 5.4 M, a computational cost of 15.2 GFLOPs, and real-time inference capability (56.2 FPS). Edge-deployment feasibility is validated via on-device benchmarking on three Jetson platforms (Nano, Xavier NX, and Orin Nano), where INT8 TensorRT inference achieves 16.2, 108.7, and 153.8 FPS, respectively, under one-hour continuous-inference soak tests with peak power below 16 W and steady-state junction temperatures within safe thermal margins. Statistical significance testing (p < 0.05) confirms the stability of these performance gains. These results indicate that CMF-Net provides rapid and accurate detection of various track intrusions, enabling robust real-time monitoring in dynamic railway environments and enhancing operational safety and intelligence. Full article

A transverse fracture occurred in U75V pearlitic rail after 5 months of service on a sharp radius curved track of mixed passenger-freight railway. Systematic tests including chemical composition analysis, mechanical properties testing, macroscopic fracture inspection, metallographic observation and microscopic morphology characterization were conducted on the failed rail sample. The results indicate that the rail base metal has qualified metallurgical quality. Its chemical composition, fundamental mechanical properties and microstructure fully meet the requirements of Chinese railway standard TB/T 2344.1-2020. The failure mode is identified as instantaneous brittle fracture. Severe mechanical extrusion and impact cause prominent plastic deformation on the rail foot, leading to surface plastic flow and further triggering micro-crack initiation. Under continuous cyclic stress induced by train loads, the micro-crack tips undergo repeated tearing and closing. Severe stress concentration accelerates the formation of transgranular cracks, which propagate rapidly and unstably toward the rail interior, eventually resulting in catastrophic transverse fracture. Standardized procedures in rail transportation, hoisting and laying are essential to avoid mechanical damage, while regular line inspection and timely replacement of damaged rails should be strictly enforced. Full article

The increasing energy demand and environmental impact of transportation systems have intensified the need for more efficient railway energy management strategies. Although electric railway systems provide a sustainable alternative, the dynamic nature of traction power systems and the inadequate use of regenerative braking energy still result in significant energy losses. In order to improve energy efficiency and state-of-charge (SOC) stability, this study proposes an optimized fractional-order proportional-integral (FOPI) controller for the control of a wayside energy storage system (ESS) in a DC railway network. The parameters of the FOPI controller are tuned via recent metaheuristic tool of barrel theory-based optimizer (BTO) such that the error between the desired and actual charging/discharging voltages of the ESS is minimized under nonlinear and time-varying operating conditions. The BTO is characterized by strong exploration/exploitation balance that prevents the approach from falling in local optima. Also, the approach has low sensitivity to user-defined parameters. The proposed approach was evaluated using a MATLAB/Simulink (version 2021b) model of a double-track DC railway system incorporating realistic train operations and three distinct traffic scenarios including ideal, perturbed, and stochastic conditions. The BTO was compared to other approaches of particle swarm optimization (PSO) and gray wolf optimizer (GWO). Also, statistical tests using the Friedman, Kruskal–Wallis, ANOVA, and Wilcoxon rank tests were conducted to assess the suggested approach. The obtained results confirm the robustness and competence of the proposed controller compared to either the conventional static control approach or optimized controller via the comparable approaches. As a result, the suggested controller achieved higher total energy savings, improved utilization of regenerative braking energy, and enhanced power demand distribution across substations. While minor increases in SOC deviation were observed in certain scenarios, the overall system performance showed improved robustness and adaptability. These findings highlight the effectiveness of integrating fractional-order PI control designed via the suggested BTO for advanced energy management in railway applications. Full article

With the rapid expansion of high-speed railways, maintaining track structural health is vital for modern railway systems. Although deep learning has improved defect detection, models still face problems such as varying defect scales, severe background noise (e.g., lubricant residues and ferruginous oxidation), and irregular defect boundaries. To solve these problems, we introduce a new network named Rail-Adaptive-RCNN (RA-RCNN). It uses a Large Selective Kernel (LSK) backbone to dynamically adjust the Effective Receptive Field (ERF) for capturing periodic corrugation. We also added an Efficient Multi-Scale Attention (EMA) module that purifies features by suppressing noise without lowering dimensions. Finally, combining Scylla-IoU (SIoU) Loss with K-means clustering optimizes the regression of odd-shaped defects. Our experiments indicate that RA-RCNN reaches a mean Average Precision (mAP_0.5) of 86.2%, outperforming the baseline Faster R-CNN by 8.8%. Corrugation detection specifically reached 91.4%. With a processing speed of 26 FPS, this method effectively meets the practical needs of real-time automated railway maintenance. Full article

Additive manufacturing through a laser cladding has been shown to be an effective technology for the mitigation of wear and rolling contact fatigue (RCF) of railway track. Small-scale tests have consistently shown that creating a thin layer of premium material on the tribo-active surface of the railhead vastly reduces wear and suppresses the onset of RCF due to the ratcheting mechanism being almost eliminated in comparison to standard rail material. Cladding reduces material plastic flow by 60% which is a cause of insulated track joint failure. This paper reports results from the first full-scale trials of additively manufactured laser clad layers on railway rails by studying their mechanical properties and microstructure. This is a vital step in safely progressing this technology from lab scale to network application. Tested full-scale insulated block joint (IBJ) specimens, clad with martensitic stainless steel (MSS) and Stellite 6, were sectioned, polished and etched and the microstructures of the clad, heat-affected zone and parent rail materials were inspected using optical and scanning electron microscopy (SEM) (Hitachi TM3030 plus, Tokyo, Japan). Residual stress was also measured. Cladding with MSS and Stellite 6 showed high wear and RCF resistance after the tests. Material flow was reduced with the clad layer applied. No defects such as porosity or large precipitates were observed in the heat-affected zone (HAZ), particularly close to the rail surface at the clad end which could act as a point of weakness. Residual stress states varied between materials, MSS being compressive (−344 MPa average) and Stellite 6 being tensile (+391 MPa average) which could have an impact on the fatigue life of the clad. This finding matches previous work, indicating that MSS may be preferable in the field, where bending of rails can occur. Overall, the work showed that laser cladding can provide a good solution to lipping issues and wear problems of rail in IBJs. Analysis in this work confirmed that the HAZ where clad meets the bulk rail at the surface has good structural integrity; however, this needs to be a focus of attention in field application of these layers. Full article

Railway track assets may suffer from different types of degradation due to aging, traffic conditions, environmental conditions, and natural and man-made hazards, which affect their performance in terms of reliability and availability, as well as passenger safety and comfort. By knowing which variables influence the degradation and performance of railway tracks, and the most appropriate maintenance and renewal actions, it is possible to define the most appropriate Performance Indicators. The use of predictive models to forecast these indicators can support the decision-making process during the maintenance management over time. In this work, a proposal including the selection of the most appropriate Performance Indicators is presented, together with a brief overview of predictive models used for railway systems. Based on that, a holistic framework to forecast the railway track performance aiming to support the decision-making process is given and its applicability is discussed. The proposed framework integrates the selection, processing, and aggregation of different types of Performance Indicators within a predictive modelling framework, enabling the analysis even when data availability is limited. The applicability of the framework is demonstrated through an illustrative example based on inspection data. The results illustrate the evolution of track condition states over time within a probabilistic framework. Full article

Optimizing high-speed railway (HSR) timetables requires coordinated decisions on train stopping patterns and local feasibility constraints, such as headway separation and service ordering, particularly at stations where consecutive trains share infrastructure. As network size and service density increase, station-level interactions can induce strategic behavior among trains competing for overlapping passenger markets. This study introduces a delayed-feedback evolutionary game framework to model interactions between two trains under incomplete information. Here, “delayed feedback” represents the lag in information transmission and periodic strategy updates, rather than operational train delays. We first formulate replicator dynamics for the non-delayed scenario, deriving equilibrium points and local stability conditions. The model is then extended to include delayed feedback in payoff evaluation, and the impact of delay parameters on stability and convergence is analyzed. To account for operational heterogeneity, two station layouts are considered: (i) two tracks per direction, representing small stations with limited overtaking and stop–pass combinations, and (ii) four tracks per direction, representing large stations that allow simultaneous stopping and richer operational patterns. Numerical simulations examine convergence, oscillatory behavior, and parameter sensitivity. Results indicate that delayed feedback significantly influences system dynamics: small delays maintain convergence to evolutionarily stable strategies, whereas larger delays induce persistent oscillations and complex transient trajectories. Station layout further affects stability regions and long-term strategy profiles. This study is based on analytical derivation and numerical simulation rather than sample-based statistical inference; therefore, non-parametric hypothesis testing is not applicable in the present framework. This framework provides a game-theoretic and stability-oriented tool for station-level timetable analysis, offering methodological guidance for timetable design under delayed decision feedback in HSR operations. Full article

The occurrence of short-wave corrugation with wavelengths of 32–44 mm on curved sections of urban express railway lines is particularly pronounced, yet the underlying initiation mechanisms have remained insufficiently understood. Furthermore, conventional mitigation strategies—including the installation of rail dampers and passive grinding—entail substantial maintenance expenditures, thereby hindering their large-scale application. To elucidate the initiation mechanisms of rail corrugation and to formulate effective control measures, the characteristic corrugation parameters under various track structure configurations across an entire alignment were first measured and systematically analyzed. Dynamic interaction models between vehicles and three distinct track typologies were subsequently developed, together with a comprehensive analytical framework for corrugation evolution. The wheel–rail dynamic response characteristics and corrugation growth rates corresponding to each track type were examined, and the wheel–rail coupled vibration modes that exacerbate corrugation propagation in urban express lines were identified. The instantaneous wear behavior of the rail under differing creep regimes was also investigated, leading to the proposal of a novel self-mitigating approach for rail corrugation. The results demonstrate that the excitation frequency of rail corrugation is predominantly confined to the 600–700 Hz range, exhibiting a fixed-frequency characteristic that remains invariant with respect to curve radius, track structure type, and operational speed. An interesting finding is that, although the intrinsic vibration properties of different track structures diverge significantly, the third-order bending resonance of the rail segment situated between bogie wheels is largely unaffected by track-borne vibrations and manifests as a localized wheel–rail resonance within the vehicle–track coupled system. This particular resonance markedly accelerates corrugation development and is identified as the critical governing factor for corrugation initiation in urban express lines, regardless of the underlying track configuration. Furthermore, rail instantaneous wear displays a substantial phase shift under varying creep conditions, with the wear profiles under creep saturation (full sliding) and low creep (rolling–sliding) exhibiting a distinct anti-phase relationship. This insight underpins a novel self-wear suppression strategy: by intentionally mixing rolling–sliding and full-sliding operational regimes, destructive interference between the out-of-phase wear contributions is achieved, resulting in a considerably attenuated corrugation growth rate compared with exclusive rolling–sliding operation. This methodology thus offers a promising and fundamentally new alternative for the long-term management of rail corrugation through intrinsic wheel–rail interaction. Full article