In order to analyze the development and current research status of urban rail transit network performance evaluation, in urban rail transit networks this paper conducts a quantitative analysis of the literature from the CNKI database based on CiteSpace software. This paper gradually focuses on three levels of research: urban rail transit, urban rail transit network, and urban rail transit network performance evaluation, and analyzes the information such as the number of publications, authors, literature sources and keywords. By tracing the important literature, the main indicators of rail transit network performance evaluation are summarized, and the advantages and disadvantages of different evaluation methods are commented. The results show that the research on performance evaluation of urban rail transit networks is undergoing several important transformations. Firstly, the analytical model is developed from unweighted network to weighted network model, which pays more attention to the differences between stations and intervals. Secondly, the research object was extended from the analysis of rail transit network to the comprehensive evaluation of coupled transportation networks such as railroad and railbus. Finally, the research focus of network performance has gradually shifted from the resistance ability under disasters or external shocks to the resilience evaluation including the postdisaster recovery ability.

With accelerating global urbanization, traditional rail transportation faces challenges in capacity bottlenecks and the need for efficiency improvements. The development of the lowaltitude economy, particularly Unmanned Aerial Vehicles (UAVs) and electric Vertical TakeOff and Landing aircraft (eVTOLs), provides new solutions for rail transportation systems. This paper explores the integration of the lowaltitude economy with rail transportation, analyzing its potential in improving urban traffic efficiency and promoting the development of smart cities. The paper discusses the key technologies and practical applications of the integration f perspectives: integration motivation, technological foundations, and application scenarios. By introducing visual perception, communication, control, multisensor fusion, and safety technologies, the lowaltitude economy can enhance inspection efficiency, construction monitoring, and emergency response capabilities within rail transportation systems. This paper aims to provide a practical discussion on the integration of the lowaltitude economy and rail transportation, further advancing the development of smart city transportation systems.

This study systematically researches and discusses service quality evaluation for the construction of highdensity urban rail transit stations in the context of China's rapid economic and urbanization development. Based on the previous results, 21 evaluation factors in five dimensions, namely, environmental safety, business and service, spatial design, ecology, and humanistic care, are proposed in conjunction with field research and national standard documents. Field surveys are carried out with Shenzhen and Hong Kong metro stations, with a total of 553 valid questionnaires collected onsite, to study the importance of the service elements as well as the satisfaction of metro users as perceived by them. Through the IPAKANO model, this paper constructs the correlation matrix of implicit and explicit importance of service elements and determines the improvement priority of service elements in metro stations. The results show that the comprehensive scores of commercial diversity and station commercial condition elements are low, and the comprehensive scores of guidance system, station rest facilities, and entrance/exit design elements are high. Based on the results, this paper proposes a strategy for optimizing the design of metro station facilities and space based on service quality improvement in terms of different priorities and levels of importance. This paper innovatively applies the IPAKANO model to the optimization of service quality of rail transit stations, and constructs a more targeted evaluation system of service elements by combining the analysis methods of explicit and implicit importance.

Data plays a crucial role in the successful deployment of urban rail transit large language models (LLMs). RetrievalAugmented Generation (RAG) technology emerges as a promising approach for developing industryspecific LLMs and mitigating hallucination issues. However, the lack of comprehensive industry knowledge bases hinders its effectiveness. This study proposes a novel framework for constructing a knowledge graphbased RAG knowledge base for urban rail transit LLMs. This framework consists of four key dimensions: classification skeleton, semantic benchmark, feature rules, and logical relationships. These dimensions are implemented through entity classification systems, terminology dictionaries, attribute libraries, and entity relationship tables, respectively. By incorporating industryspecific attributes for entities, this approach goes beyond the traditional subjectpredicateobject triple structure of knowledge graphs, resulting in a comprehensive and multifaceted representation of industry knowledge. This knowledge base serves as the core component of the RAG system, providing standardized, reliable, and traceable domain knowledge through a systematic pipeline of data collection, structuring, vectorization, and knowledge representation. This process significantly enhances the reliability and domain expertise of the content generated by urban rail transit LLMs, paving the way for a new era driven by both data and knowledge.

Addressing the current challenges in urban rail transit line reconstruction, such as insufficient network synergy, path dependency in equipment updates, and the lack of upgradability design, this study explores theoretical innovation directions. It proposes key strategies, including incorporating upgradability into the equipment performance evaluation system, decoupling equipment from lines for networkoriented reconstruction, and improving the overall network functionality through clustered line reconstruction. These theoretical innovations aim to systematically promote the reconstruction of existing lines, reduce the cost of equipment upgrades, improve maintenance efficiency, and drive the sustainable development of the urban rail transit industry. Based on the framework of Guidelines for reconstruction of existing urban rail transit lines in China, this study addresses critical challenges in urban rail transit reconstruction, including insufficient network coordination, path dependency in equipment upgrades, and inadequate upgradability design. It proposes a comprehensive theoretical framework with four key innovations: integrating "upgradability” into equipment performance evaluation systems; implementing networkoriented decoupling of equipment systems from physical infrastructure; enhancing overall network functionality through clustered line reconstruction approaches; and developing derivative, regenerative, and symbiotic systems for rail transit reconstruction based on the "productionlivingecology" theory of urban renewal. These theoretical advances provide systematic solutions to optimize network functionality, reduce equipment replacement costs, enhance maintenance efficiency, and promote sustainable development in the urban rail transit sector. The proposed framework offers valuable guidance for policymaking and implementation strategies in urban rail transit modernization.

The existing decentralized rectification scheme for direct current (DC) lighting systems in metro stations faces several challenges, including low power supply reliability and efficiency, high cable costs, significant distribution losses, and difficulties in unified equipment maintenance and power quality management. To address these issues, this paper proposes a centralized rectification scheme for metro station DC lighting systems. The study begins with an analysis of the system architecture, current status, and limitations of the existing decentralized scheme, followed by a detailed presentation of the proposed centralized solution, including its system architecture, DC power supply configuration, key components, and required system modifications. A comprehensive comparison between the two schemes is conducted using actual engineering data, focusing on system losses, costs, harmonic content, and operational reliability. The results demonstrate that compared to the decentralized scheme, the centralized rectification scheme requires less feeder cable usage and achieves lower system costs. It also shows significant improvements in reducing cable losses, increasing system power efficiency, and decreasing harmonic content. Furthermore, the power modules in the centralized scheme operate under more favorable conditions, leading to enhanced system stability. Based on these advantages, the centralized rectification scheme proves to be a more suitable solution for DC lighting systems in metro stations.

The lowaltitude economy has become a new industrial direction pursued in global competition due to its prominent features. The research on lowaltitude economy in the field of urban rail transit is rapidly developing and growing. For the low and medium capacity rail transit systems represented by the straddle monorail system, based on the key technology research of low altitude technology, it is necessary to explore a low altitude unmanned aerial vehicle intelligent inspection system that is suitable for the construction and operation characteristics of straddle monorails, meets operational requirements, and effectively solves maintenance problems. This study proposes for the first time a video intelligent inspection system based on an unmanned aerial vehicle platform applied to straddle monorail transit, analyzes its application plan scheme and value in straddle monorail transit, and explores a practical and feasible low altitudeeconomic economy application scenario for the low and medium capacity rail transit systems mainly based on elevated laying structures. This approach is conducive to achieving the automation of straddletype monorail transit track beam and bridge inspection. This approach is effective in Reducing the workload of manual inspections and minimizing manual omissions has significant implications for the industry.

Guided by the need to address the shortcomings of subjective selection and the mismatch between capacity and demand in the selection of existing medium and low capacity urban rail transit standards, the standardized and procedural decisionmaking system for standard selection is developed. Firstly, the 4 criterion and 16 index evaluation system is established, considering constraints such as peak hour passenger flow, minimum transport capacity reserve, and the number of train operations. A multiobjective optimization model is constructed to determine the set of candidate rail transit systems. Besides, the CRITICTOPSIS algorithm is constructed to determine the weight coefficient values of each indicator and the optimal solution distance, thereby determining the optimal track system. Finally, using the Sline as the background for example verification, 5 alternative track systems are evaluated through a quantitative model. The CRITIC and TOPSIS algorithms were implemented using Python software. The decision values of rail transportation system rank in the order of selfguided monorail, crossseat monorail, light rail, guideway rubber wheel and low and mediumspeed magnetic levitation, indicating that the optimal rail system for line S is the selfguided monorail. Analyzing the standardized scoring matrix and index weight values of each type of rail system, the research results show that the model and algorithm proposed in this paper can effectively solve the problem of low and mediumcapacity rail transportation system selection.

Relying on a subway station entrance and exit channel pipe jacking project, combined with the onsite monitoring data for jacking parameter inversion, the refined pipe curtaincorridorstrata pipeline corridor jacking finite element model considering the locking joints was established. The deformation of strata with and without pipe curtain is analyzed comparatively, and the necessity of pipe curtain is verified. Then, the effects of pipe diameter, pipe spacing and pipe thickness on surface settlement, pipe curtain cost and joint gap were systematically investigated through comprehensive tests, and a comprehensive evaluation system of TOPSIS was established to evaluate the adaptability of the pipe curtain with game combination assignment. Subsequently, BPNN was used to fit the mapping relationship between the pipe curtain parameters and the adaptability, and finally the genetic algorithm was used to search for the optimal parameter combinations. The study shows that the parameter that has the greatest influence on the adaptability of the pipe curtain is the diameter of the steel pipe, followed by the clear distance of the steel pipe, and finally the thickness of the steel pipe. Considering the safety, water resistance and economy, the recommended design parameters of the locking pipe curtain are the steel pipe diameter of 990 mm, the steel pipe thickness of 20 mm, and the steel pipe clearance of 160 mm.

To study the effectiveness and impact of rail transit development in developing countries and to improve urban development experiences based on the TransitOriented Development (TOD) model, this study takes the Addis Ababa Light Rail Transit (LRT) as a case study to analyze its effects on residents' commuting and the spatial distribution of jobs and residences after its completion. Based on official city maps, resident questionnaires, and interview data, a multiple linear regression model was employed to analyze the influence of different commuting methods on commuting time. The findings indicate that the light rail system has a limited effect on improving residents' commuting efficiency. Further GIS spatial analysis reveals that the overall distribution of residential and employment areas in the city is uneven, with suburban residential density being exceeding five times that of urban areas. The analysis results reflect that the failure to coordinate land use with the development of the light rail corridor is a primary reason for the low commuting efficiency. The conclusions advance the understanding of the adaptability and implementation strategies of the TransitOriented Development (TOD) model in countries with lowdensity sprawl and relatively underdeveloped economies.