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.

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.

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.

In response to the increasing operation and maintenance pressure and efficiency requirements of urban rail transit, a comprehensive management and control platform based on digital twins and multisystem integration is constructed and implemented to achieve intensive and refined operation and maintenance management of subway stations and improve management efficiency and service levels. Through 3D scanning of existing lines, this paper focuses on the development and implementation of an integrated management and control platform based on digital twin technology and multisystem integration, enhancing management efficiency and service quality. Firstly, a digital twin model is constructed to represent the operation of urban rail systems. The study explores model lightweight technology and uses 3D rendering engines to render and optimize large models and large scenes. In addition, this paper studies multisource heterogeneous data fusion technology through data standardize processing to realize the processbased collection and storage of heterogeneous data of various professions. Furthermore, a comprehensive urban rail management and control platform is developed, integrating functional modules to meet the needs of various disciplines. This platform improves the execution efficiency of operation and maintenance tasks by 30%, increases the accuracy of equipment and facility status monitoring to 98%, and increases the success rate of preventive maintenance by 20%. The efficiency of cross-disciplinary data sharing and collaborative work is enhanced by over 60%, resulting in a shortened fault response time, significantly improved accuracy of equipment and facility status monitoring, and enhanced effectiveness of preventive maintenance.

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.

To address the issue of not being able to provide an opencut receiving well at the receiving end of rectangular pipe jacking, this study analyzes the soil prereinforcement scheme used in the construction of rectangular pipejacking reception. It explores the appropriate structural type for the castinplace section of the abandoned shell and proposes a waterproofing scheme between the castinplace section of the abandoned shell, the precast pipe joints, and the hidden beams and columns of the station. t This study is based on the new entrance project of Jingjiang Road Station on Tianjin Metro Line 2. The processes, including the shutdown of the pipe jacking machine and grouting, are also optimized. Practical results show that the proposed scheme ensures the safe construction of the abandoned shell reception, with monitoring data indicating a maximum surface settlement of 12.12 mm. The key technology proposed in this paper are highly feasible and effective, offering a new design approach for similar projects, such as abandoned shell reception, where construction site limitations exist.

The urban rail transit projects in China have adopted overhead contact system power supply and dedicated rail return current scheme to solve the problem of stray current leakage. However, there are currently no applications of dedicated rail return under contact rail power supply systems in China. This article proposes four dedicated rail return current schemes based on the contact rail power supply systems. It analyzes and evaluates these four schemes through quantitative and qualitative methods, considering aspects such as equipment impact, vehicle current return, networked operation of lines, power supply system protection, safety, and costeffectiveness. It discusses the feasibility, advantages, and disadvantages of each scheme, and ultimately recommends a dedicated rail return scheme based on the contact rail power supply system. Finally, it proposes a recommended dedicated rail return scheme based on the contact rail power supply system, and summarizes the impact of dedicated rail return on other disciplines.

The control of micro deformation of adjacent buildings during the construction of deep foundation pits in weak strata is one of the challenges in the geotechnical field. Taking the construction project of subway deep foundation pit of adjacent buildings in soft ground in Hangzhou as an example, this paper introduced the micro deformation control technologies such as the reinforcement technology of underground continuous wall trough wall, sleeve valve pipe grouting reinforcement technology, servo steel support system, and the reinforcement and excavation technology of underground middle wall, and analyzed the deformation characteristics and the effect of micro deformation control technology in the construction of deep foundation pit of adjacent buildings in soft ground. The results indicate that the sleeve valve pipe grouting reinforcement technology reduces the impact of construction on the surrounding building group and suppresses its deformation; the deformation of the enclosure structure and surrounding deformation can be suppressed through slot wall reinforcement technology, and the quality of the enclosure structure has been improved; the servo steel support system effectively suppresses the deformation of the enclosure structure and reduces the impact of construction on the surrounding area; cross wall and block excavation technology suppresses building deformation and weakens the impact of spatiotemporal effects. In the end, the surrounding buildings of the deep foundation pit basically achieved the goal of "micro deformation”.

In order to solve the problem that the traditional monitoring analysts in the field of urban rail transit have a high falsenegative rates and complex parameter adjustment of abnormal behaviors such as falling, fainting and fighting, making them difficult to apply efficiently to actual urban rail station monitoring scenarios, this paper proposes a human posture feature recognition framework based on skeleton pattern recognition, introducing the attitude estimation technology based on human skeleton. The Alpha Pose model is used to accurately estimate the posture of passengers, and combined with the Spatial Temporal Graph Convolutional Networks model, it achieves abnormal behavior recognition in the monitoring scenario of urban rail stations. By achieving 72.3 mAP on the COCO dataset and 82.1 mAP on the MPII dataset, the performance is improved by up to 17% compared to the OpenPose model, verifying the effectiveness and practicality of the model. The results show that the method proposed in this paper not only improves the recognition speed of passenger behavior but also has the ability to adapt to complex scenarios, providing a new technical solution for urban rail safety monitoring.