To improve the inspection level of Beijing Subway interval facilities, and achieve cost reduction and efficiency improvement, the inspection basis of interval facilities was clarified based on the national standard, industry method, local standard and enterprise standard. The automatic inspection equipment and way of inspection of Beijing Mass Transit Railway Operation Corp. Ltd. were discussed. The functional parameters, advantages and disadvantages of typical comprehensive inspection equipment were compared and analyzed. The comprehensive inspection mode of Beijing Subway interval facilities was presented. The results indicate that the enterprise standard can cover the inspection contents and inspection cycles in the national standard, industry method and local standard. The comprehensive detection vehicle is suitable for dynamic inspection, while the comprehensive detection car is suitable for static inspection, both of which are far superior to the handheld equipment. The onboard detection equipment is mainly used for routine inspection. The comprehensive detection vehicle and the comprehensive detection cars combined with the existing professional detection equipment are mainly used for scheduled inspection. The fixed monitoring system and the handheld equipment are mainly used for special inspection. The comprehensive inspection should be implemented by leasing service in the short term, and by purchasing equipment in the long term. This study can serve as a reference for promoting intelligent operation and maintenance of urban rail transit infrastructure.

During longterm operation, the cooling system's heatsink intake can become clogged with environmental impurities and dust, reducing cooling airflow and affecting thermal dissipation efficiency. This can lead to overheating faults in the power converter, significantly reducing its operational reliability. To address the issue of dust blockage in the aircooled system, which can cause overheating faults in rail transit power converters, a realtime online monitoring method for the cooling system's thermal dissipation state is proposed. This method uses the thermal resistance of the heatsink, extracted from the power device and heatsink cooling curves, as a characteristic parameter. The GaussNewton iterative method is employed to extract these parameters, which are used to identify the degree of blockage and achieve online monitoring of the cooling system's thermal dissipation state. Simulation and experimental results validate that the proposed method effectively monitors the cooling system's operational state, demonstrating superior detection efficiency and effectiveness compared to traditional blockage detection methods.

This paper presents a comprehensive assessment of embedded rail technology implementation in existing metro line renovation through the case study of Xiaogang Station. The research examines the technical challenges, innovative solutions, and construction methodology employed in this pioneering project. The construction background, distinctive features, construction procedures, and solutions to the construction challenges encountered are introduced in detail. By comparing the preand postrenovation vibration, noise and Track Quality Index (TQI) on track, along with the monitoring of the postrenovation track condition, this study demonstrates the effectiveness of embedded rail track renovation in enhancing the performance of existing lines. The results indicate that this technology can significantly improve the vibration and noise reduction performance of the line while ensuring the continuity and safety of existing line operations.

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.

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.

The Autonomous Train Operation System (TACS) is the development direction of future urban rail transit signal systems and is partly being applied in some urban rail transit. Different from traditional CommunicationsBased Train Control (CBTC), no unified TACS standard has been established yet. This paper aims to analyze the engineering applicability of existing TACS system degradation schemes. Based on the working principle of TACS, this paper discusses the necessity of configuring a degraded system. Drawing from the current development status of the TACS system, this paper summarizes three feasible TACS degradation schemes, introduces the architectures and working principles of different degradation schemes, and qualitatively analyzes the three TACS degradation schemes from the aspects of system composition, application scenarios, and tracking ability under degradation situation. The study establishes the train tracking time model under degradation situation, and simulates the degradation train tracking scenarios of three TACS degradation schemes under the same engineering conditions. Based on the simulation results, it identifies the factors that affect the efficiency of degradation tracking. Building on the above research, the key conditions for the TACS degradation system are summarized, and the engineering applicability and application effects of the three degradation schemes are analyzed, leading to several improvement suggestions. The results of this study have significant implications for the promotion and application of Train Autonomous Operation System.

In order to ensure personal safety, overvoltage protection devices (OVPD) are usually installed in stations and depots of operating lines. However, the overvoltage generated during the reset of the rail potential limiting device may cause the OVPD section II to act or even lock, resulting in the rail potential limiting device short circuiting the ground and rail, becoming a path for stray current leakage. With the continuous increase of urban rail operation mileage, stray currents have caused serious problems such as DC bias in the surrounding power system and corrosion damage to the urban pipeline network, which have seriously threatened the safe operation of the power system and oil and gas system. This paper proposes a suppression method for the overvoltage caused by the misoperation of the rail potential limiting device caused by abnormal rail potential, which exacerbates the leakage of stray currents in urban rail transit. The method involves constructing a simulation model of the overvoltage generated by the OVPD opening of the rail potential limiting device, constructing an arc experimental platform using N1250 contactors, and conducting grid mounted testing on actual lines. The results show that after using the overvoltage suppression method proposed in this article, the peak operating overvoltage generated by the opening of the rail potential limiting device is significantly reduced, reducing the possibility of OVPD misoperation and stray current leakage.

The network operation of urban rail transit has introduced diversity in passenger route choices. It is difficult to accurately determine passengers' network route choices based on existing Automatic Fare Collection (AFC) transaction data and probabilistic inference methods. This difficultyaffects tasks such as rail transit network passenger flow allocation and ticket clearing. This study utilizes network station information to construct an urban rail topology network. The proposed method searches for feasible path sets for OriginDestination (OD) pairs and uses multisource data, including AFC transaction data, mobile signaling data, and train schedule data, to build a nonlinear optimization model to infer passengers' travel route choices. Experiments based on the Nanjing Metro network show that the model is effective and robust. This study can provide guidance for urban rail transit operations and ticket clearing.

The government has proposed establishing a dedicated public safety chapter within the preliminary design documentation for urban rail transit systems. This study examines the compilation and review processes for this public safety chapter. The research first analyzes public safety risks and security standards in urban rail transit, proposing a modular approach to the chapter's organization. This comprises three key modules: counterterrorism and riot control, emergency management, and law enforcement support. Secondly, the study establishes that the review framework should be comprehensive, hierarchical, and forwardlooking. It systematically categorizes the primary review criteria across three dimensions: legal regulations, technical standards, and policy requirements. Finally, for the review process itself, the research proposes a fivestage framework: project initiation, preliminary assessment, onsite evaluation, formal review, and completion. For each stage, the study defines the participating departments, work scope, and required documentation. The findings have established standardized workflows for all phases and stakeholders involved in both compiling and reviewing the public safety chapter. This framework serves as a valuable reference for provinces and municipalities implementing similar initiatives.

Given that passenger flow distribution in urban rail transit station facilities is limited by the capacity and topology of these facilities, making quantification difficult, this study addresses this issue by analyzing the current state of research on passenger flow in station facilities. First, an analysis of the passenger flow state and its transformation within station facilities is conducted. Based on the capacity and transit capacity of the facilities, a passenger flow state transition model is constructed using queuing theory to describe the probability of congestion and dissipation at facility junctions. Taking an urban rail transit interchange station as an example, an analysis of the passenger flow distribution characteristics on the walking facility topology network is performed. The results show that when passenger flow density exceeds the density of free flow, congestion inevitably occurs in facilities with smaller capacities due to the actual passenger flow surpassing a certain threshold. The actual passenger flow distribution characteristics are influenced not only by the capacity of individual walking facilities but also by bottlenecks within the facility network. The research results provide data and technical support for station managers in developing and implementing flow restriction schemes.