Search Results (821)

High-speed railways (HSRs) generate repeatable and spatially extended seismic wavefields, providing useful signals for distributed acoustic sensing (DAS)-based vibration analysis. This study develops an integrated measurement framework for two characteristic frequency eigenquantities in HSR-induced seismic wavefields: train frequency and bridge frequency. Building on established spectral-line, cepstral, and Doppler descriptions of HSR seismic wavefields, we systematize the relevant theoretical expressions, compare frequency-domain correlation and cepstral strategies for train-frequency estimation, and derive a velocity-independent bridge-frequency estimator from paired Doppler-shifted components. DAS data collected along viaduct sections of the Beijing–Guangzhou HSR are used to evaluate the framework across single trains, dense observation traces, and multiple train events. The results show that bridge frequency is more stable than train frequency, with lower measurement variance. The frequency-derived train speeds and carriage lengths fall within typical operating ranges of Chinese HSR trains, and the observed spatial periodicity in frequency measurements is consistent with bridge pier spacing. These findings support accurate frequency measurement and preliminary estimation of train speed, carriage length, and wave velocity from DAS records. Together, they clarify measurable frequency parameters of HSR seismic sources and establish a quantitative source-characterization basis for DAS-based railway vibration analysis and future multi-source monitoring studies. Full article

Railway transport management has changed dramatically over the past 50 years. The advent of computer technology and the capacity for information transmission brought greater safety and the ability to remotely control interlocking devices. These enable the centralisation of railway transport management, leading to higher operational efficiency and reduced staffing costs. At the same time, this technological progress has enabled the development of additional automation functions, which we can abbreviate as ARS (Automated Route Setting). The international designation Automatic Route Setting (ARS) includes actions that enable the automation tool to execute instructions to the signal box without the intervention of operating personnel (the dispatcher). Their importance increases with line speed and the size of the remotely controlled area. Thanks to them, the dispatcher gains time because the ARS can automatically resolve some operational situations or allow the dispatcher to address them in advance, thereby distributing the workload over a wider time window. However, the interlocking system itself remains the primary safety mechanism and will prevent ARS if any element of the infrastructure is occupied. At the same time, it is not possible to automate safety-critical functions that require direct assistance from the operating personnel. In the article, the authors analysed functions in which ARS is currently widely used. In the next part, they focused on the possible expansion of the palette of these functions that could be included in the ARS regime using multi-criteria analysis. The WSA method was applied using data obtained from routine users of the system. This approach enabled the incorporation of practical operational experience into the evaluation process and provided an empirical basis for assessing and prioritising the analysed functions. The next step was a safety-critical analysis and determination of the conditions under which they could be included in the ARS regime. The safety-critical functions are left aside. It is assumed that these will still have to be performed by the operator, not by the ARS. Detailed implementations and quantification of their impacts on the dispatcher’s activities are then carried out for selected ARS functions. The analysis therefore yields a prioritised ranking of ARS functions, indicating the order in which their implementation would be most appropriate from an operational perspective. This ranking provides a systematic basis for the phased deployment of ARS functionalities, considering their expected operational benefits and practical applicability in railway traffic management. The last part of the article is a look into the future, because the development in the field of safe communication between the train and the infrastructure (V2I) and the transmission of valid information provides many new challenges not only in the field of ARS itself, but also in the optimisation of the entire process of managing and organising rail transport. If we can use the ARS functions today, it is only a matter of technical development to be able, for example, to guide trains to the exact time when a train route will be built for this train. This will also enable optimising the train’s energy consumption and tracking capacity use. The ideal state is when the infrastructure fully communicates with the train in GoA4 mode and optimises both the train’s ride and the use of the infrastructure. Full article

Energy Strategy 2050 promotes photovoltaic (PV) deployment to reduce fossil fuel dependence in Switzerland. However, limited available land constrains conventional solar farms, motivating the deployment of linear PV (LPV) systems along transport corridors such as highways or railways. This paper contributes to a systematic design and modeling methodology for an LPV power plant interconnected through a medium-voltage direct current (MVDC) collection network. The main methodological contribution is the development of a modified iterative modified nodal analysis (MNA) framework tailored to LPV–MVDC systems. In long-distance feeders with high line impedance, nonlinear voltage–current coupling becomes significant. These nonlinearities cannot be accurately captured by conventional MNA assuming fixed current injections. The proposed iterative approach can more accurately capture these effects compared to conventional MNA. A case study of a 5 km railway-based LPV system is investigated to present the design and modeling methodology, including layout design, network modeling, and cable sizing. The LPV power plant reaches a peak power of 3.4 MW and requires 40 DC/DC converter stations rated at 100 kW each. Cable analysis shows that 6 mm² copper conductors satisfy voltage drop limits at a string level, while 95 mm² conductors maintain MVDC voltage variations within 3%. These results highlight technical feasibility of MVDC-based integration for efficient long-distance renewable energy distribution. Full article

Reliable radio coverage is essential for the deployment of 5G for railway (5G-R) communication systems in complex railway-line environments. Previous simulation- and measurement-based studies have mainly focused on main-track railway scenarios, while the propagation characteristics in railway-side obstructed environments remain insufficiently characterized. To address this gap, this paper investigates large-scale propagation characteristics using passive synchronization signal reference signal received power (SS-RSRP) measurements collected from a 5G-R test network. Typical railway-line scenarios, including open line-of-sight (LOS) propagation, building-obstructed railway-side sections, viaduct-blocked regions, and depot-like environments, are analyzed to reveal the influence of railway-side structures on large-scale signal behavior. A floating-intercept (FI) model is adopted to characterize scenario-dependent path loss, and a height-corrected FI refinement is further introduced for building-obstructed sections. The results show that local railway-side structures introduce distinct and quantifiable excess propagation loss beyond conventional distance-dependent path loss. The obtained model parameters can support large-scale propagation modeling, link-budget margin design, coverage-hole identification, and wireless coverage evaluation for 2100 MHz 5G-R systems in obstructed railway-side environments. Full article

This study proposes a marker-assisted method for measuring railway platform position using forward-view images captured from in-service trains. Conventional monocular-image-based approaches have limited applicability to precise infrastructure measurement because they suffer from depth-related uncertainty. To mitigate this limitation, the proposed method uses installed ground markers on the platform and sleepers, known marker dimensions, measured installation offsets, and track geometry information. The selected marker reference lines and points define a local transverse measurement plane under near-frontal imaging conditions. The method consists of YOLO-based marker detection, lens-distortion correction, DIC-based marker localization, local pixel-to-metric scale conversion, and vector-based geometric calculation. Field experiments were conducted on an operational regional railway line. When lens-distortion correction and the marker-center-based reference were used, platform gap estimation achieved an MAE of 4.6 mm, an RMSE of 5.3 mm, and a maximum absolute error of 8.8 mm. Platform height estimation improved after lens-distortion correction, with the MAE reduced from 14.2 mm to 9.0 mm, although the maximum absolute error remained 21.2 mm. These results suggest the feasibility of platform gap monitoring under the tested straight-track and near-frontal imaging conditions. Full article

Energy-efficient operation of railway systems is of great importance for both environmental and economic reasons. Minimizing net energy consumption helps to achieve such energy-efficient operation. In this paper, the train’s speed profile and headway between trains are controlled to achieve lower traction energy consumption and higher train synchronization for better regenerative braking energy utilization. Eventually, the net energy consumption, defined as the difference between the traction energy consumption and the utilization of regenerative braking energy, is minimized. Two optimization problems are defined to solve the problem efficiently. The first main problem is to find the optimal speeds at each segment of the railway track. The second sub-problem’s objective is to find the optimal values of travel time, dwell time, and headway for every suggested solution to the main problem. Both problems are solved using the genetic algorithm. Numerical results are based on the actual operation data of the Beijing Metro Yizhuang Line in China. In the numerical results, the proposed strategy of dividing the problem into two problems and the use of variable headway shows an enhancement in reducing net energy consumption by 7.5% compared to other strategies in the literature. Full article

Train fires in railway bridge–tunnel connection sections (BTCSs) create severe evacuation challenges because tunnel–bridge spatial transitions interact with heat, smoke, visibility loss, and constrained rescue conditions. Existing evacuation management methods remain limited in coupling quantitative risk assessment with adaptive route guidance under evolving fire hazards. To address this issue, this paper proposes a large language model (LLM)-enhanced intelligent decision-support system (IDSS) framework for quantitative risk assessment and dynamic evacuation routing in BTCS fire scenarios. First, a multi-dimensional risk assessment model is established using the analytic hierarchy process and fuzzy comprehensive evaluation to quantify post-stop evacuation risk from the perspectives of evacuation organization, structural damage, and line recovery. Second, a dynamic topology-based routing method is developed to prune fire-threatened nodes and identify safer evacuation paths under evolving hazard conditions. The risk assessment model and routing algorithm are further embedded as callable tools into an LLM-enhanced evacuation IDSS under a perception–reasoning–recommendation architecture, in which an LLM orchestrates tool invocation, situational reasoning, and recommendation generation, thereby enabling autonomous risk interpretation, dynamic route replanning, and cross-regional collaborative decision support. The proposed framework is validated through a representative real-world railway engineering case. The results show that the IDSS-recommended routes achieved higher comprehensive safety scores (80.44 and 79.56) than routes involving fire-affected areas did (77.00 and 77.88). Workflow analysis further indicates that the proposed IDSS reduces the manual route-derivation workload by integrating risk assessment, topology pruning, and route allocation into structured, human-reviewable evacuation recommendations. Expert evaluations further confirm the rationality and compliance of the outputs, with review scores ranging from 1.76 to 1.92 out of 2.00. Overall, the proposed framework offers a feasible decision-support approach for intelligent evacuation management in complex railway fire emergencies. Full article

Using the Suzhou East Station integrated transportation hub as a case study, this paper investigates the train-induced vibration responses and their distribution patterns under various operating conditions of high-speed railway lines, intercity lines, and subway lines. The results show that train speed is the dominant factor: the high-speed railway passage controls floor vibrations in most stories, while line distance also plays a role for some floors. No significant amplification is observed under multi-train convergence; the vibration level is similar to that of the most unfavorable single-train condition. Therefore, only the most unfavorable single-train condition needs to be considered. As vibrations propagate upward through the floors, high-frequency vibrations gradually attenuate while low-frequency vibrations are amplified, leading to an overall amplification of vibrations at the top floors of some buildings. The floor vibration response level decreases as the vertical stiffness of the structural member increases. Cantilevered slabs and mid-span areas are vibration-sensitive zones. For station–city integrated transportation hubs with high-speed railways running underneath, track vibration mitigation measures should be prioritized, such as thickening the track slab. Thin side-wall vibration mitigation pads have a poor vibration reduction effect. When diaphragm walls are rigidly connected to the station and buildings, they amplify the building’s vibration response. Full article

Train-induced vibrations pose a significant threat to foundation pit slopes adjacent to railways during parallel construction or line renovation projects. To address this issue, this paper proposes a periodic steel-sheet pile barrier for vibration mitigation in narrow construction sites. Firstly, field tests were conducted along the Qinbei Railway in China. The acceleration time history and dominant frequency (27.6 Hz) of ground vibrations were obtained. Secondly, based on periodic structure theory, the dispersion relations and band-gap characteristics of periodic steel-sheet piles were analyzed using the finite element method. Parametric studies were then performed to investigate the effects of key factors, including periodic constants, pile spacing and pile count per unit cell, and construction deviations, on the band-gap boundaries and width. Subsequently, frequency-domain, time-domain, and slope stability analyses were carried out to evaluate the isolation performance. The results show that the optimized barrier, with parameters of a = 1.6 m, D = 0.1 m, n₁ = n₂ = 4, and L = 2S, reduced the peak acceleration by 70% and achieved a vibration reduction of up to 88% at the dominant frequency. Furthermore, slope stability analysis revealed that the barrier increased the factor of safety from 1.16 to 1.46, exceeding the code-required minimum of 1.2–1.3. This study provides a potentially cost-effective and construction-friendly solution for protecting temporary foundation pit slopes from train-induced vibrations in railway-adjacent areas. Full article

Railway transportation networks increasingly share constrained corridors with transmission lines, buried pipelines, and other linear infrastructure. Electromagnetic interference in these corridors is important for safe railway planning and operation, particularly when nearby high-voltage lines cross oil and gas pipelines. This paper investigates transmission-line-induced pipeline potential under crossing conditions in the Zhangbei region. The CDEGS moment-method framework is applied with locally refined segmentation in the crossing regions, and an electromagnetic coupling model for multiple-crossing transmission line-oil and gas pipeline systems is established. The qualitative effects of crossing angle and parallel length on pipeline potential were obtained under both normal operating conditions and single-phase ground fault transient conditions. The results show that induced voltage decreases nonlinearly as the crossing angle increases and rises markedly with crossing length. The contribution of ground potential rise during transient processes to pipeline potential is significantly greater than that during steady-state processes. Installing zinc ribbons as a drainage measure can reduce the pipeline-to-ground voltage. However, supplementary mitigation measures may still be required under severe interference conditions. These findings are relevant to railway transportation because railway corridors often coexist with transmission lines and buried pipelines, making coordinated electromagnetic compatibility assessment essential for infrastructure safety and operational reliability. The proposed framework supports corridor planning, risk assessment, and protective design for railway-related infrastructure in complex shared corridors. Full article

Precise fault localization for high-speed railway continuous transmission lines is indispensable for sustaining power supply reliability and mitigating power outages. This study presents a novel fault localization approach that uses low-voltage information obtained from box-type substations distributed along continuous transmission lines. The proposed scheme relies on the distribution features of the positive-to-negative sequence voltage ratio ($r_{PNV}$) measured at the low-voltage terminals of box-type substations. Results reveal that the magnitude of $r_{PNV}$ gradually declines from the main substation to the fault location in the fault upstream area, while it stays nearly unchanged in the downstream section. Based on this feature, the faulted section is initially determined by means of the nearest neighbor clustering method. Subsequently, the precise fault location is calculated by solving equations that combine the sequence voltage ratio at the fault point with the measurements obtained from the main substation and box-type substations downstream of the fault. The proposed method requires only asynchronous low-voltage measurements, eliminates the need for fault impedance modeling, and is applicable to various asymmetric faults. Simulation tests under different fault types, fault resistances (up to 2000 Ω), noise conditions, and neutral grounding modes demonstrate that the method achieves high accuracy and robustness. Full article

Electrification of public transit is central to sustainable urban development, yet it introduces passenger exposure to extremely low-frequency magnetic fields (ELF-MFs), which the International Agency for Research on Cancer (IARC) classifies as possibly carcinogenic to humans (Group 2B). This study presents a systematic cross-platform comparison of ELF-MF exposure in direct current (DC) light rail and alternating current (AC) heavy rail systems operating under a single national regulatory framework. A total of 9100 continuous measurements were collected across 28 trips on the Tel Aviv Red Line light rail transit (1500 V DC) and the Israel Railways Tel Aviv–Binyamina corridor (25 kV, 50 Hz AC) during 23–26 November 2025, using calibrated Tenmars TM-192D gaussmeters. Mean passenger seat magnetic flux density was 0.226 ± 0.147 µT (2.26 ± 1.47 mG) for the DC system and 0.900 ± 0.606 µT (9.00 ± 6.06 mG) for the AC system. The difference was highly significant (Welch’s t = −73.06, p < 0.001). DC light rail exposure remained consistently below Israel’s precautionary 0.4 µT (4 mG) threshold for continuous public exposure, whereas AC heavy rail mean levels exceeded this threshold in every monitored trip while remaining far below ICNIRP general public reference levels. These findings highlight a “Green Dilemma” in sustainable transport policy: the environmental benefits of rail electrification must be balanced with prudent electromagnetic exposure management in jurisdictions applying strict precautionary limits. Full article

The extensive development of high-speed railway (HSR) networks often necessitates construction activities adjacent to operational lines. However, existing studies have mostly focused on the substructure construction phase, lacking systematic consideration of cumulative effects throughout the construction process. This study proposes an integrated framework for risk-informed monitoring throughout the full construction process. The framework integrates the Analytic Hierarchy Process (AHP), triangular fuzzy numbers, and fuzzy comprehensive evaluation to construct a quantitative risk assessment model, decomposing the construction process into hierarchical risk factors and quantifying the weights of each factor. Furthermore, a non-contact real-time monitoring system based on Digital Image Correlation (DIC) is designed and deployed, enabling high-frequency, high-precision three-dimensional pier deformation measurement. Applied to a new bridge crossing the Beijing–Shanghai HSR, the risk model identified pile cap and pier construction as the highest-risk stage (weight: 0.311). The DIC system, validated against total station measurements (relative error < 5%), recorded cumulative pier deformations across 31 construction stages, all remaining within the ±1.2 mm early warning threshold, thereby validating the proposed risk assessment model. The integrated AHP-Fuzzy and DIC framework provides a robust paradigm for proactive risk management, confirming that risk-informed monitoring ensures construction impacts on existing HSR infrastructure remain within safe limits. Full article

The southeastern coastal region of China is extensively influenced by the circum-Pacific geothermal activity, particularly during the excavation of deep-buried tunnels, where the confined space leads to the accumulation of heat flow, resulting in high-temperature and high-humidity environments. These conditions are detrimental to both the physical and mental health of workers and the safe operation of equipment. Based on this, the Lijiashan deep-buried high-temperature tunnel along the Wen-Yu High-Speed Railway (Wenling-Yuhuan) was selected as a case study. Field monitoring was conducted to assess the surrounding rock stress, temperature distribution characteristics of the surrounding rock and structure, and the humid and high-temperature environment within the tunnel during construction. A comprehensive evaluation index considering both temperature and humidity was employed to evaluate the tunnel construction environment. The results indicate the following: (1) During tunnel excavation, the maximum surrounding rock pressure occurs at the arched shoulder, and the fractures induced by blasting effectively relieve stress, mitigating the risk of rockburst. (2) The seepage paths of the surrounding rock are redistributed during excavation, converging towards the invert, with the osmotic pressure being approximately 10 times that of the upper structure. (3) The temperature at the tunnel face, secondary lining, and surrounding rock is significantly influenced by the heat released from concrete hydration. The closer the surrounding rock is to the support structure, the higher the temperature, with the secondary lining reaching up to 58.6 °C and the working area up to 35.2 °C. (4) Water spraying can reduce the temperature in the construction area by approximately 0.65% at the Kelvin temperature conditions, but it increases humidity by about 16%. The average humidity levels within the tunnel are 75.3% during the day and 87.5% at night. (5) Evaluation of workers’ physiological parameters reveals that the humid and high-temperature environment during tunnel construction is consistently unfavorable for workers’ health. Full article

Despite the widespread adoption of model predictive control (MPC) in railway research, the integration of intelligent learning mechanisms into train control systems operating under moving block signaling remains limited, particularly in approaches that preserve constraint satisfaction and industrial feasibility. To address this gap, this paper presents a novel learning-based model predictive control (LMPC) framework for high-speed train control under the moving block signaling principle. Moving block signaling dynamically enforces safe inter-train separation based on the absolute braking distance, imposing stringent safety, comfort, and performance constraints on train operation. The proposed LMPC exploits the repetitive nature of railway operations by progressively improving its control policy through the incorporation of historical operational data into the terminal set of the optimization problem. This learning capability enables the controller to optimize train behavior on a given line while pursuing different control objectives, namely maximum-speed operation for leading trains and minimum safe inter-train separation for following trains, in full compliance with signaling requirements, speed limits, actuator constraints, and comfort-related jerk bounds. Simulation results on a representative high-speed line show that, compared with a conventional non-learning MPC, the proposed LMPC achieves a measurable reduction in traction-related energy consumption while maintaining comparable speed profiles, travel times, and strict constraint satisfaction. These improvements are achieved through a single software-level modification of the train control algorithm, without requiring additional onboard hardware or infrastructure upgrades, positioning the proposed LMPC as a promising and practically viable solution for energy-efficient deployment in high-speed railway operations. Full article