Search Results (88)

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

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

Stray-current corrosion from DC-electrified railways drives premature failure of buried metallic infrastructure (pipelines, foundations, tunnel reinforcement), causing resource waste, repair-driven carbon emissions and service disruptions that undermine the sustainability of urban transit corridors. Conventional impressed-current cathodic protection (ICCP) design relies on uniform-anode rules of thumb or closed commercial codes that cannot quantify the trade-off between protection uniformity, energy use and hardware cost. We present an open MATLAB framework that couples a custom 3D finite element method (FEM) solver with multi-objective particle swarm optimisation (MOPSO) and minimises three competing objectives simultaneously: total impressed current, RMS deviation from the protection target, and number of active anodes. A laboratory-calibrated coupling factor ($\mathrm{CF}=1.98$, consistent with the image-method prediction of 2 for a highly conductive pipe inclusion) absorbs the pipe–soil interface kinetics into a single direct FEM solve, and a pre-computed Green’s-function basis accelerates each MOPSO evaluation by more than two orders of magnitude. The solver is validated against an instrumented prototype with RMSE $=14.9$ mV across ten Cu/CuSO₄ saturated reference electrode (CSE) measurements, and applied to a 500 m DC traction line. At an identical total current of 20.30 A across five anodes, the optimised design achieves an RMSE of 86.6 mV against the $-850$ mV NACE target, whereas a conventional uniform layout produces severe over-protection (RMSE $=1107$ mV)—a twelve-fold reduction. The framework is recommended as a transparent, reproducible engineering tool that simultaneously extends pipeline service life and reduces rectifier energy demand, supporting UN Sustainable Development Goals 9 and 11 for sustainable urban-rail infrastructure. Full article

In response to environmental degradation and social inequities exacerbated by automobile-dependent urban sprawl, this study proposes a framework for dynamic delineation and vitality assessment of 15-min walkable neighborhoods, using Baohe District, Hefei, China as a case study. Static service catchments were constructed using POI and road network data, then refined using one week’s mobile phone signaling trajectories calibrated to actual walking behavior, yielding 143 validated living circles (out of 156 initially delineated). These circles are classified into five typologies: commercial-residential, industrial-residential, educational-residential, predominantly residential, and public-service-oriented. A dual-index system—Facility Vitality Index (FVI) and Population Vitality Index (PVI)—is developed and synthesized into a Composite Vitality Index (VI) through normalization and weighting. Results show that only 27.3% of living circles achieve high vitality in both dimensions, indicating widespread service–demand misalignment. Conversely, 61.5% exhibit low or very low vitality, forming a “vitality depression” around the urban periphery—a pattern of service poverty with significant socioeconomic implications. High-vitality circles cluster along the Binhu New District corridor, while low-vitality circles concentrate in industrial parks (e.g., Feinan Industrial Park) and transport hubs (e.g., Hefei South Railway Station). The historic core lacks micro-infrastructures, whereas new districts—despite high-standard amenities—suffer from weak pedestrian activity. To address these deficiencies, we propose a differentiated zoning strategy: retrofitting micro-infrastructures in legacy neighborhoods, applying Transit-Oriented Development (TOD) principles in new urban extensions, and integrating community-serving functions within industrial peripheries. This framework provides actionable protocols for data-informed governance of 15-min living circles. Full article

Mixed steel/polyethylene gas distribution pipelines are increasingly used in congested urban environments where conventional layouts are restricted by existing underground utilities, safety constraints, and site-specific construction conditions. In such systems, buried steel transition sections may become particularly vulnerable to electrical perturbation and corrosion, especially when installed near electrified transport infrastructure. This paper presents a field case study on a recently installed mixed steel/polyethylene gas distribution pipeline located on Lunca Street, Petroșani, Romania, approximately parallel to an electrified railway. Electrical and electrochemical investigations were carried out eight months after installation and included 24 h monitoring of pipe-to-soil potential versus Cu/CuSO₄, 24 h monitoring of alternating current pipe-to-soil voltage, mixed alternating current and direct current signal visualization, and coating insulation resistance measurements. The results showed that alternating current pipe-to-soil voltage was present at all monitored points, with weighted mean values ranging from 0.41 to 1.23 Vrms, while pipe-to-soil potential values ranged from −0.120 to −0.238 V versus Cu/CuSO₄. Although the measured average coating insulation resistance remained relatively high, the combined electrical and electrochemical data indicate that alternating current interference associated with the nearby electrified railway is the most plausible dominant contributing source of the recorded electrical perturbation. Within the analyzed site perimeter, no other nearby electrical infrastructures with comparable interference potential were identified. The highest alternating-current exposure and the least favorable electrochemical values were recorded on the longer metallic segment, showing that metallic length and local configuration strongly influenced the severity of the effect. A mitigation strategy based on polarized electrical decoupling and dedicated grounding is proposed as a practical means of improving electrical safety and reducing corrosion risk in the exposed and buried steel sections. Full article

This paper investigates the quality of mobile network coverage along the Riga–Tukums railway corridor with a focus on the performance of 4G and 5G technologies. Ensuring reliable mobile connectivity along suburban railway corridors remains a significant technical challenge due to mixed forest–urban propagation conditions, macro-cell-dominated LTE infrastructure, mobility-induced channel variability, and fluctuating passenger density. Unlike high-speed railway environments that are extensively studied in dedicated 5G-R scenarios, suburban railway systems often rely on existing macro-cell deployments, where coverage continuity, signal quality stability, and capacity constraints must be addressed simultaneously. This study presents a measurement-based evaluation of 4G and 5G radio performance along the Riga–Tukums railway corridor under real operational conditions (50–90 km/h). Classical propagation models (Okumura–Hata and COST231-Hata) are quantitatively validated using MAE and RMSE metrics, followed by correlation analysis between RSSNR and QoS indicators. A theoretical Doppler sensitivity assessment (80–200 km/h) is conducted to evaluate mobility robustness across LTE and 5G frequency bands. Mobility transition regions and handover-related time windows are geometrically estimated, and passenger density-based capacity modeling is applied to assess throughput degradation under peak occupancy scenarios. Based on these results, a multi-layer network planning strategy integrating 700 MHz macro coverage, 1700 MHz capacity enhancement, and 3500 MHz 5G NR deployment is proposed. The optimization strategy resulted in an estimated 22–28% increase in stable service coverage in previously weak-signal zones and demonstrated that propagation model deviations remain within ranges comparable to recent railway studies (≈15–25 dB RMSE). These findings provide a structured framework for suburban railway communication optimization and support the gradual modernization of railway infrastructure toward FRMCS-ready architectures. The study illustrates the applicability of modern modelling tools for assessing and improving mobile communication systems and contributes to the broader development of digital infrastructure within Latvia’s transport sector. Full article

Metro train timetable rescheduling (TTR) is a critical task for ensuring the reliability of urban rail transit systems. However, with the increasing density of railway networks and the growing number of operational trains, TTR has evolved into a typical high-dimensional and large-scale optimization problem. Traditional mathematical programming and heuristic approaches often struggle with the “curse of dimensionality” and fail to provide real-time responses under stochastic disturbances. To address these challenges, this paper proposes a novel framework based on Multi-Agent Deep Reinforcement Learning (MADRL). Specifically, we model the TTR problem as a decentralized cooperative process and utilize the Multi-Agent Advantage Actor-Critic (MAA2C) algorithm to optimize train schedules dynamically. The proposed framework is implemented within the Flatland simulation environment, which allows for the representation of complex arbitrary topologies. We design a composite reward function that minimizes total delay deviation while maximizing passenger satisfaction, subject to constraints such as headway, operating time, and train capacity. Furthermore, to enhance the robustness of the model against high-dimensional state uncertainties, random disturbances following a negative exponential distribution are introduced during training. Experimental results across various scenarios—ranging from simple dual-track to complex random networks—demonstrate that the MAA2C-based approach significantly outperforms traditional baselines. It not only achieves faster convergence in small-scale scenarios but also demonstrates superior computational efficiency and scalability in large-scale environments, effectively minimizing passenger waiting times. This study validates the potential of MADRL in solving high-dimensional traffic control problems for intelligent transportation systems. Full article

The construction of high-speed railways (HSRs) is the core engine for promoting the economic integration and spatial structure optimization of the Guangdong–Hong Kong–Macao Greater Bay Area (GBA). Changes in land use along HSR corridors are inextricably linked to the efficacy of regional coordinated development and ecological protection initiatives, as well as the realization of regional sustainable development. Nevertheless, past relevant studies exhibit prominent limitations. First, the lack of effective methodologies for the intuitive comparison of multiple research subjects makes it difficult to accurately portray the differential characteristics of land use across various HSR routes. Second, the insufficient comprehensive analysis of the dynamic evolution of landscape patterns along routes, coupled with the absence of intuitive spatial visualization expressions, fails to explicitly reveal the spatiotemporal differentiation of landscape fragmentation, which hinders sustainable land resource utilization and ecological protection. To address these gaps, this study introduces the intensity comparison map and the comprehensive index map of landscape fragmentation and takes six typical HSRs in the GBA to conduct an intuitive comparative analysis of land use changes along multiple routes. Results show that land use evolution along HSRs presents distinct phased characteristics, with construction land acting as the core driving factor. Its proportion increases continuously, while the proportions of cultivated land and water bodies decline dramatically. Significant disparities exist in land use evolution across different HSR routes, which are closely associated with the natural and economic conditions of the traversed regions, reflecting the heterogeneous adaptability between individual routes and regional development dynamics. High landscape fragmentation areas are predominantly distributed in the transition zones between construction land and natural landscapes; fragmentation intensifies during the planning and construction phases and stabilizes or even diminishes along certain routes during the operation phase, with human activities identified as the pivotal influencing factor. This research deepens the understanding of the interaction mechanism between transportation infrastructure and land use changes in the GBA and provides a scientific basis for sustainable HSR construction planning, the rational utilization of land resources, and the coordinated advancement of ecological protection in the GBA and other similar regions worldwide, thus facilitating the sustainable development of high-density urban agglomerations globally. Full article

Urban railway networks play a central role in reshaping urban spatial structures, commercial activity, and population distribution. This study investigates how different transfer hub types in Seoul—a megacity with one of the world’s densest rail systems—affect nearby commercial clusters, active population agglomeration, and land values. We classify 298 stations into single-line (non-transfer) and multi-line transfer types and examine three aspects within a 500 m station catchment area: the density of surrounding commercial areas, active population agglomeration derived from mobile phone data, and land price changes using government-assessed land values from 2016 to 2024. To capture local variations, commercial areas were categorized as Developmental Commercial Areas, Commercial Alley Areas, and Traditional Markets. The results show that multi-line transfer hubs host denser commercial facilities and attract larger active populations than single-line stations. Active population varies significantly by station type, averaging approximately 1520 persons near single-line stations, 1969 near subway–subway transfer hubs, and 1637 near subway–rail transfer hubs. However, land price increases were more strongly influenced by the overlap and extent of station catchment areas than by transfer type alone. Robustness checks using alternative catchment specifications indicate that the main qualitative land-price patterns are stable with respect to the definition of the influence area. These findings contribute to understanding of how transfer hierarchy influences urban agglomeration and provide policy insights for typology-based transit-oriented development (TOD) planning in megacities. Full article

The Jiangsu Yangtze River city cluster is a key growth pole of the Yangtze River Economic Belt, yet substantial disparities in development levels persist across cities, and the role of rail transit investment in fostering regional economic coordination remains insufficiently understood. This study aims to reveal the dynamic mechanisms through which railway transportation investment influences regional economic growth via population migration and service industry agglomeration, and to quantify the economic multiplier effects under different investment scenarios. Considering the close economic linkages among cities, spatial autocorrelation analysis is applied to assess intercity economic dependence, which provides the basis for developing a system dynamics model that links the rail transit system with the regional economy. Using data from eight core cities over the period 2014–2023, the model is employed to simulate long-term economic responses under different investment scenarios. The results indicate that increasing the rail transit investment ratio from 0.0077 to 0.02 is associated with an estimated 13.2% increase in regional GDP by 2030, with a corresponding economic multiplier of approximately 1.8, while simulation errors remain within 4.1–16.2% compared with historical data. The findings suggest that rail transit investment promotes regional growth through improved accessibility, factor agglomeration, and industrial upgrading, and that coordinated planning at the urban agglomeration scale is more effective than isolated city-level strategies. By integrating spatial dependence analysis with system dynamics modeling, this study offers a dynamic perspective on the regional economic impacts of rail transit investment. Full article

The adaptive reuse of industrial heritage is increasingly recognized as an effective low-carbon strategy that reduces resource consumption, lowers embodied carbon emissions, and supports sustainable urban transitions. Developing appropriate reuse strategies, however, requires a robust understanding of heritage value. As material evidence of China’s modern industrialization, railway-associated industrial heritage possesses the characteristics of linear cultural heritage. Yet systematic and multi-scalar value assessments from a linear heritage perspective remain limited. Focusing on the Guanzhong Section of the Longhai Railway—one of the most representative industrial development axes in Northwest China—this study establishes a two-level value assessment framework and conducts a comprehensive evaluation of fourteen textile industrial heritage units. At the individual level, five dimensions—historical significance, architectural features, structural integrity, authenticity, and rarity—were assessed through field investigation, and type-specific weights were introduced to correct structural imbalances between quantity and value across building categories. At the unit level, the Analytic Hierarchy Process (AHP) was employed to determine the weights of spatial–functional integrity, process completeness, railway connectivity, industrial landscape characteristics, and the integrated individual-level value. The results show that factory workshops and warehouses consistently exhibit the highest value, whereas structures and residential buildings, despite their numerical dominance, contribute relatively little. Spatially, a clear west–east gradient emerges: high-value units cluster in Baoji and Xi’an, medium-value units in Xianyang, and low-value units mainly in Weinan and surrounding counties. The findings indicate that textile industrial heritage along the Guanzhong Section forms a railway-linked linear cultural heritage system rather than isolated sites. The proposed evaluation framework not only supports heritage identification and conservation planning but also provides a theoretical basis for promoting low-carbon adaptive reuse of existing industrial buildings. Full article

Urban railway systems are critical for the daily lives of citizens in cities. Considering that urban railways are a core infrastructure, it is important for urban and railway practitioners to operate and maintain urban railway systems effectively and to maximize user satisfaction. However, despite the importance of this topic, research on the factors that contribute to high levels of railway user satisfaction in the context of Southeast Asian developing countries remains limited. To address this gap, this study conducted an exploratory case study using the Jakarta Mass Rapid Transit (MRT). This study collected 406 valid responses regarding Jakarta MRT user satisfaction through a face-to-face questionnaire survey and analyzed them using regression analysis, fuzzy-set qualitative comparative analysis (fsQCA), and text-mining techniques, which have seldom been applied in previous research on factors influencing railway user satisfaction. The results indicate that high levels of satisfaction with railway fares and social considerations—particularly the combination of both—may be the simplest configuration associated with higher overall user satisfaction, while various other combinations of satisfaction dimensions could also lead to elevated satisfaction. The results also suggest that all dimensions may serve as necessary and/or sufficient conditions for high satisfaction, implying the importance of considering all dimensions. These findings are specific to this case study and may differ depending on the socio-cultural contexts. To advance the understanding of satisfaction factors, further comparative research on the Jakarta MRT and rail systems in other countries is warranted. Full article

Urbanization and the growing scarcity of surface land resources have highlighted the strategic importance of underground space as a critical component of sustainable urban infrastructure. This study presents a multi-objective optimization framework for underground infrastructure planning around transit hubs, aligning with the principles of Transit-Oriented Development (TOD). By integrating an agent-based model (ABM) with the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and incorporating the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), the framework forms a unified evaluation and optimization tool that accounts for user behavior while addressing competing objectives, including minimizing evacuation time and functional conflicts, maximizing functional efficiency, and reducing layout deviations. Using Qingdaobei Railway Station in China as a case study, the method yields notable improvements: a 15% reduction in evacuation time, a 16% increase in development benefits, and a more balanced spatial configuration. Beyond technical gains, the study also discusses station planning and governance under the TOD policy context, highlighting how integrated layouts can alleviate congestion, strengthen functional synergy, and support sustainable urban development. Full article

Prefabricated ballastless tracks are increasingly applied on long-span bridges, necessitating special attention to driving safety and comfort at weak connection areas like beam-end expansion joints. This study, based on the Ningbo-Xiangshan urban railway’s Xiangshangang sea-crossing bridge, establishes a refined train–track–bridge dynamic interaction model incorporating the beam-end expansion joint zone. The dynamic response characteristics of the train under temperature-induced deformation in beam-end expansion area conditions were explored. The research results show that the temperature-induced deformation of the end area of the long-span cable-stayed bridge has a greater impact on the vertical dynamic response of the train, but has a small impact on the lateral dynamic response of the train. Among them, the overall temperature rise and fall state of the long-span cable-stayed bridge has a significant impact on the dynamic response of the train. When a train passes through the beam-end expansion area, compared with the prefabricated track, the beam end area has a more obvious impact on the dynamic response of the train, but its scope of influence is only limited to the telescopic transition within the segment range. The temperature-induced deformation in the beam end area will have a greater impact on the dynamic response of the train, but the dynamic response of the train can still be controlled according to the relevant limits in the current standard. The results of this research can provide technical support for laying prefabricated tracks on large-span urban railway bridges, and provide technical reference for the optimization of expansion joints in the beam end area. Full article

China has entered a period of urban renewal, with the focus shifting from large-scale incremental construction to both upgrading existing building quality and adjusting incremental structures. There are three main types of urban renewal: demolition and reconstruction, comprehensive improvement, and organic renewal. The latter systematically optimizes and enhances urban functions, spaces, and culture through gradual renovation methods and is, therefore, suitable for use in ancient cities. To promote organic renewal, the problem of limited space resources must first be addressed, which can be resolved to a certain extent by the moderate development of underground spaces; preliminary evaluations of the development potential are also required. In consideration of the demands of organic renewal, we constructed a novel indicator system for evaluating underground space development potential (USDP) in ancient cities that assesses two dimensions: development demand and development suitability. A multi-factor comprehensive evaluation method was adopted to quantify the indicators of USDP, taking Shaoxing Ancient City (SAC) as the case study. According to the USDP evaluation, SAC can be divided into four kinds of areas: high-potential, general-potential, low-potential, and prohibited development areas. High-potential areas accounted for 16.38% of the total evaluation area and were primarily concentrated in or near key locations: train transit stations (Shaoxing Railway Station), public service facilities, evacuated land, and cultural and tourism facilities around historic districts (Shusheng Guli Historical and Cultural Street). The proposed development strategies for these areas included the interconnection of metro stations, redevelopment of relocation-related and vacated land, construction of underground cultural corridors, and supplementation of parking facilities. For developed underground spaces with low utilization efficiency, functional renewal and management improvement measures were put forward. Our method of evaluating the USDP of ancient cities and the strategies proposed to optimize the utilization of underground space can provide reference examples for SAC and other similar ancient cities. Full article