Search Results (69)

Cross-border multimodal transportation systems are essential for regional connectivity, yet their structural concentration, modal imbalance, community organization, and accessibility differentiation remain insufficiently understood from an entropy perspective. Based on 2024 data, this study constructs railway, highway, aviation, and integrated transportation networks between Western China and the five Central Asian countries. It integrates complex network analysis, structural entropy, modal diversity entropy, Louvain community detection, and accessibility assessment within a structure–organization–function framework. The results reveal a core–periphery pattern, with Xi’an, Urumqi, Almaty, and Tashkent serving as hubs. Structural entropy shows that highway connections are balanced, aviation links are concentrated around core hubs, and the integrated network reflects the coexistence of core-hub agglomeration and multimodal coverage expansion. Modal diversity entropy indicates that high connectivity does not necessarily imply balanced modal configuration, and 41.8% of nodes remain dependent on a single mode. Community detection reveals local cohesion and global segmentation, while accessibility analysis identifies a Western China core and Central Asian periphery. Sensitivity analyses based on common-node normalization, travel-time weighting, and alternative modal weights confirm the robustness of the findings. These results provide an integrated diagnostic framework for identifying structural concentration, modal imbalance, and accessibility inequality in cross-border multimodal transportation networks. Full article

Railways constitute a core component of China’s national comprehensive transportation network, and their spatial organization and temporal accessibility jointly shape transport integration and system efficiency. Identifying their evolution from the dual perspectives of spatial expansion and time compression is therefore of both theoretical and practical significance. Drawing on fractal theory, this study examines the structural characteristics, evolutionary trends, and driving factors of railway networks in China’s five major urban systems from 2014 to 2024 from a “space–time” dual perspective. The results show that railway networks exhibit a staged pattern of “spatial filling preceding temporal correlation”, with a lag of approximately 1–8 years—about 1 year in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA), 5 years in the Middle Yangtze River (MYR) region and Beijing–Tianjin–Hebei (BTH), and up to 8 years in the Chengdu–Chongqing (CC) region. In addition, clear regional differences are observed: the Yangtze River Delta (YRD) is polycentric, with the greatest potential, projected to continue rapid spatial growth until 2027 and to remain in a fast-growth phase of temporal correlation; GBA is highly coordinated; BTH is developed but characterized by dual-core agglomeration; CC grows rapidly with lagging functionality; and MYR is corridor-dependent with limited potential. These findings indicate that network functionality does not emerge synchronously with infrastructure expansion, but depends on subsequent improvements in operational organization and service capacity. Compared with single-scale-based indicators, the “spatial distribution–temporal correlation” framework more effectively captures network performance and provides quantitative support for transport optimization and coordinated regional development. Full article

The imbalance of urban public transport networks often leads to traffic congestion. Traditional planning prioritizes system optimization and single-mode travel, neglecting interactions between different modes. From an economic perspective and based on passenger travel behavior, this paper constructs a reasonable path set for multimodal networks. Using information entropy, it establishes multidimensional indicators including site path diversity entropy, destination regional entropy vectors, and weighted comprehensive entropy. Regional aggregation and coefficient of variation analyze internal balance, while scatter plots and the Gini coefficient measure global resource allocation equity. ArcGIS Pro 3.4.3 is employed for spatial analysis and visualization. An empirical study of Beijing’s six central districts reveals significant spatial heterogeneity in path distribution across functional zones: working areas exhibit concentric patterns, commercial areas form corridor agglomerations, residential areas have the highest entropy values, and transport hubs are relatively balanced. Cluster analysis based on entropy vectors effectively identifies commuter, residential, and hub station types. Some hubs show an ideal “high richness, low imbalance” state, while areas like Beijing Railway Station exhibit “low richness, high imbalance.” The Gini coefficient of 0.1864 indicates relatively balanced public transport resources overall. The “route-region-demand” collaborative analysis framework constructed in this study achieves a paradigm shift from static network structure to dynamic human-oriented evaluation, providing methodological support for equity assessment, network optimization, and resource allocation in multimodal public transport networks, and can contribute to the equitable and balanced sustainable development of public transport. 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

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

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

As a core factor in advancing urban agglomeration development and new urbanization, the structural resilience of multi-modal transportation networks in metropolitan areas directly determines their disturbance resistance during emergencies and their sustainable development. To address the prevalent “core–peripheral” connectivity imbalance in medium-sized metropolitan areas, this study takes the Jinan Metropolitan Area as an empirical case to systematically explore its multi-modal transportation network’s structural resilience. A three-dimensional evaluation framework of “absorbing capacity–buffering capacity–recovery capacity” was built based on complex network theory. Network efficiency was used to measure absorbing capacity, the average number of independent paths was used to characterize buffering capacity, and structural entropy was used to determine recovery capacity. The entropy weight method was used to calculate integrated multi-dimensional resilience values, and a sequential node failure simulation was used to analyze network invulnerability. The main findings are as follows: (1) The Jinan Metropolitan Area’s multi-modal transportation network has “small-world characteristics” but low density, with trunk line coverage gaps. (2) Sub-networks differ significantly. The railway sub-network performs best, the highway sub-network is the weakest, and the composite network achieves resilience balance through multi-modal collaboration. (3) Node failure analysis reveals that “core hubs are resilience pillars, while secondary highway nodes are weaknesses.” The proposed “three-dimensional evaluation framework” provides a methodological reference for resilience quantification in similar metropolitan areas, and the “trunk line densification + peripheral connection” strategy supports the implementation of metropolitan planning policies to promote modern metropolitan transportation systems with efficient commuting and robust disturbance resistance. Full article

The Middle Yangtze River Urban Agglomeration, a critical ecological barrier in China, faces escalating pressures from rapid urbanization and climate change, leading to fragmented landscapes and degraded ecosystem services. To address the synergistic challenges of ecological protection and risk management, this paper takes the urban agglomeration in the middle reaches of the Yangtze River as the study area, and obtains the source patches through morphological spatial pattern analysis. Based on the spatial distribution of risky source areas, ecological blind zones are cut down by optimizing buffer zones and merging fragmented patches. Finally, a composite ecological network is constructed through circuit theory superimposed on the dual network method. The results showed that (1) there are 16 ecological source patches and 16 risk source patches in the study area. Six complementary ecological sources and four new ecological sources were obtained through the blind zone reduction strategy. The percentage of ecological blind zones reduced from 58.4% to 39.5%. (2) The integrated nodes with 11,366 connecting edges were identified. The integrated nodes are distributed around the central Jiuling-Mafushan Mountains, mainly in the western and southern areas of the Dongting Lake Plain. (3) Primary integration nodes are critical for network stability, with a 75% node failure threshold triggering systemic collapse. The proposed strategy of “mountain protection–plain control–railway monitoring” is consistent with China’s territorial and spatial planning. By incorporating the risk network into the conservation framework, this study provides feasible insights for balancing development and sustainability in ecologically fragile areas. Full article

Budapest and its metropolitan area serve as a key railway hub both within Hungary and across Europe, intersected by multiple European rail corridors and characterized by substantial suburban traffic driven by daily commuters from surrounding areas. The Budapest agglomeration is served by 11 rail lines to Budapest managed by the MÁV Group Company (MÁV: Magyar Államvasutak Co., Budapest, Hungary) is a railway company owned by the Hungarian state). The majority of these are high-capacity, mostly double-track electrified main lines, which play a major role in long-distance and international transport. The main goal of the MÁV Group Company is the continuous development of the quality of passenger transport in Hungary and Europe, quality improvement in passenger comfort, sales, and passenger information systems, and the introduction of up-to-date, environmentally friendly means and solutions. Infrastructure plays a decisive role in the development and transformation of the country and its regions, municipalities, and settlement systems. The development of transport infrastructure not only dynamically transforms and shapes spatial structures but also initiates processes of internal differentiation. In our study, statistical analysis of municipalities and rail-based public transport confirmed a positive correlation between the modernization of transport infrastructure and selected demographic indicators. Full article

Regional comprehensive transportation infrastructures constitute the fundamental basis for the development of inland urban agglomerations. To elucidate the role of comprehensive transportation in shaping the spatial organization and expansion of urban agglomerations, this study takes the Yangtze River Middle Reaches Urban Agglomeration (YRMRUA) as a case example. It examines the spatial relationships between transportation network layout and spatial expansion patterns using fractal dimension based on traffic accessibility, traffic-weighted linear density, and Pearson correlation analysis. The key findings of this study are as follows: (1) The YRMRUA exhibits a partial fractal growth pattern influenced by transportation development, which indicates that the comprehensive transportation has a significant but limited impact on YRMRUA. (2) There is a moderate correlation between traffic-weighted linear density and spatial expansion intensity within YRMRUA. (3) Specific groups such as the Wuhan–Ezhou–Huanggang–Huangshi group, Changsha–Zhuzhou–Xiangtan group, and Nanchang–Yichun group have formed in areas where transportation development and spatial expansion are at the forefront. (4) Different modes of transportation, including waterway transportation, railway transportation, and road transportation, have varying effects on spatial expansion. The integration of these modes forms the fundamental framework of urban agglomerations. Full article

Arresters on electric multiple units (EMUs) usually experience premature aging under a high-frequency voltage and impulse current. In addition, they lead to overheating faults when subjected to the high-frequency overvoltage of electric railways. This research investigates the aging behavior of arresters when subjected to overvoltage and an impact current. An analysis was conducted on the impact of the aging duration at 1 mA and the frequency of overvoltage on a lightning arrester’s outer-layer components. The results show that the 1 mA DC reference voltage of the MOA sheet decreased, and the leakage current significantly increased at a 0.75 DC reference voltage through the aging of high-frequency voltage, and the duration of the applied voltage and the voltage bearing rate had similar effects on the two parameters. After aging, the Co and Bi elements on the surface of zinc oxide decreased and migrated to the depletion layer, resulting in a decrease in the dispersion characteristics of the zinc oxide agglomerate surface. Under the impulse voltage, the thermal stress on the surface of the zinc oxide increased, resulting in the damage to the zinc oxide grains, which aggravated the thermal stress concentration and reduced the performance of the zinc oxide. This study reveals the deterioration mechanism of high-frequency voltage- and impulse current gap-modulated MOA materials and provides a theoretical basis and data support for the development of and monitoring methods for new lightning arresters. Full article

Intercity railways are key transportation infrastructures in the interconnection of urban agglomerations. Their stations are usually distributed based on densely populated and economically active areas, and they also play roles as regional network nodes, intra-city nodes, and functional areas. However, the academic research on the spatial development of station areas is still very limited. In particular, there is no sufficient in-depth discussion about the coordinated development mechanism of the “regional node-place” and “urban node-place” of intercity railways. Based on the case study of Guangdong–Hong Kong–Macao Greater Bay Area in China (GBA), this paper provides an in-depth analysis of the regional node development level, urban node development level, station area development level, comprehensive station area development level, and coordinated development of “regional node-place” and “urban node-place” in the GBA in 2012, 2016, 2020, and 2023 by constructing a node-place model, development index of regional nodes, development level index, and coupling coordination degree model. Findings: (1) From 2012 to 2023, the development of regional nodes, urban nodes, and places of the GBA intercity railway saw a significant improvement, with the proportion of high-value stations increasing by 13.3%, 7%, and 8.8%, respectively. Despite some improvement on the whole, the three still exhibited an unbalanced spatial distribution of “high in the middle-low in the periphery”; (2) The relative gap in development levels between “regional node-place” and “urban node-place” of intercity railways decreased by 0.159 and 0.168, respectively, showing an overall upward trend, but still showing an unbalanced spatial distribution of “high in the middle-low in the periphery”; (3) The development level of regional nodes and urban nodes is lower than that of areas and is dominated by the unbalance place and dependence types, while the unbalance node and balance types account for less; (4) The coordination of the “regional node-place” and “urban node-place” of intercity railways is gradually improved, and the stations with high coordination and high coordination levels accounts for an increased proportion from 4% to 7% and 8%, respectively. However, the coordination remains at a low level on the whole, with most sites still in the low-level coupling and lower-level coupling stages. Some stations in Guangzhou, Shenzhen, Foshan, and Dongguan have witnessed a level leap and are showing a transition towards a medium to high level of coordinated development, with the surrounding areas moving away from low-level coupling and coordination. Full article

The agglomeration railway networks form the backbone of modern urban transport systems, providing safe and reliable access from home to work or school for thousands of residents of agglomeration districts. This article examines the possibilities and directions of development for the agglomeration railway of the city of Poznań, providing a comparative analysis of this system with the networks of the cities of Szczecin and Gdańsk. Each rail system was described and presented in terms of its most important features. The collected data were then collected in tabular form and based on them, a comparison was made using two methods: AHP and COPRAS. Both methods, although with different strengths, indicated the unquestionable advantage of the agglomeration railway in Gdańsk for the adopted assumptions. The Poznań network obtained the weakest result in light of the assumptions. The analysis showed aspects of passenger transport, the improvement of which is crucial for the development of public transport in Poznań, e.g., too low frequency of trains, the need to increase passengers’ awareness of the possibilities of using rail transport, or the need to create stops ensuring a smooth possibility of changing to another means of transport. Full article

The South Manchuria Railway, being the earliest constructed railway in Northeast China, has preserved a vast array of modern architectural heritage along its route, which holds significant research value. This study takes the urban agglomerations along the Shenyang–Yingkou section of the South Manchuria Railway as the research object, convening scholars from various fields to construct a hierarchy analysis model for heritage value and using fuzzy control tools to mitigate the impact of subjective cognition on the experimental results, thereby determining the weight values of the influencing factors of modern architectural heritage along the South Manchuria Railway. We invited professional scholars and stakeholders to score the modern architectural heritage, and after combining the weight values derived from the hierarchy analysis model and calculating the weighted average, the heritage value scores were determined for each piece of modern architectural heritage. This study utilizes heritage value scores to measure the degree of danger and the extent of protection required for these architectural heritages, identifies the current shortcomings and insufficiencies in the protection and renewal of these heritages, and compares the effectiveness of heritage conservation efforts in various cities and towns. Full article