To investigate the sources and distribution patterns of PM2.5, PM10, and total suspended particulates (TSP) in subway stations, this study conducted particulate matter concentration tests at 11 stations along two subway lines in a city. The test areas included outdoor locations, station public areas, equipment management rooms, and corridors inside the platform end doors. The concentrations of PM2.5, PM10, and TSP in each area were measured, and elemental analysis of the outdoor and platform particulates was performed. Subsequently, the distribution patterns of PM2.5, PM10, and TSP in various areas at different outdoor concentrations were analyzed. Based on the test results, suggestions for subway particulate matter prevention and control measures were proposed. The research revealed a significant increase in iron content in particulate matter within stations compared to outdoor areas. Particulate matter containing iron in subway stations often exhibits irregular sheetlike shapes, differing from those found outdoors, indicating that railwheel friction is the source of these particulates. When outdoor particulate matter concentration levels were low, the distribution patterns of particles of various sizes were similar, generally exhibiting higher concentrations in the tunnels than in the stations and outdoors. However, when outdoor particulate matter concentration levels were high, PM2.5 and PM10 concentrations were higher in tunnels than in outdoor areas and stations. Regardless of outdoor particulate matter concentration, TSP concentrations in public areas and carriages were consistently higher than outdoors. These findings provide valuable insights for developing effective particulate matter prevention and control measures in subway systems.

To identify key stations in urban rail transit networks and study their evolution over multiple years, we developed a key station recognition method based on truncated singular value decomposition (TSVD). We selected origindestination (OD) data from the morning peak hours between 2011 and 2019 in Beijing as the dataset. The analysis involved evaluating the evolution of network passenger flow and identifying key stations in subway networks using key eigenvectors. These results were then compared with those obtained from complex network methods. The analysis demonstrates that TSVD can effectively identify key network stations by considering the OD distribution. The outcomes from TSVD better represent the spatial distribution of network passenger flow than traditional methods. The results revealed that the spatial layout of key stations in Beijing's urban rail transit has evolved towards multiple centers, such as Northwest Xi’erqi and Southwest Fengtai Science Park. These stations are gradually forming network passenger flow centers and establishing connections. Additionally, stations like Southeast Tu Qiao and Northeast Fengbo are showing preliminary trends toward becoming network passenger flow centers.

In recent years, with the comprehensive transformation and upgrading of the national economy, Beijing's urban development model has shifted towards a more scientific, sustainable, and highquality approach. The relationship between rail transit and urban development has been reevaluated, leading to the emergence of the "urban followtrack construction" planning concept. This study examines the current issues in Beijing's rail transit system, summarizes the experiences of integrating and developing rail transit station cities, reviews recent policy guidelines related to stationcity integration in Beijing, and offers new insights and perspectives on the station planning concept for rail transit lines. In terms of urban rail transit network planning, the focus is on selecting appropriate corridors and nodes to enhance interaction with urban planning. For route planning, attention is given to resource matching between stations and surrounding land, aiming to balance the planning and construction processes for mutual benefit. By integrating the lessons learned from actual engineering projects, this new planning concept is applied to practical engineering, providing a reference for the integrated development of Beijing's rail transit station cities.

To address the challenge of effectively managing APT in urban rail transit scenarios, this paper proposes a method that combines attack source graphs with deep traffic learning. This integrated approach merges attack reconstruction with traffic monitoring to facilitate identifying and detecting APT attacks. Experimental results demonstrate that this model can effectively trace the sources of APT attacks. Compared to traditional APT attack detection models based on sandboxes or abnormal characteristics, this combined model significantly improves detection accuracy, precision, recall rate, and other performance indicators.

To address the urgent need for vibration and noise reduction in the development of upper covers, this paper summarizes existing control measures for tracking vibration and noise in depots, emphasizing the necessity of implementing seamless rails in depot lines. We also examine the requirements for sleepers. Our calculations indicate that depots can meet the strength and stability requirements for seamless lines by using arm span resistance pillows in conjunction with other strengthening measures. Additionally, this paper introduces a seamless turnout technology for No.7 movable turnouts and verifies their seamless integration based on actual usage conditions in Beijing. The findings suggest that both the turnouts and the turnout groups are suitable for seamless application. A comparative test conducted at a speed of 15 km/h reveals that the movable turnout reduces vibration and noise by 35 dB compared to fixed turnouts.

The study addressed issues related to the nonaction and delayed response times of subway station fire protection systems, focusing on optimizing the automatic pump start method for fire water supply control systems utilizing municipal direct pressurized water supply. Initially, a field test was conducted on the automatic pump start system at a subway station, followed by a detailed analysis of the test data to understand pressure and flow rate change dynamics within the fire protection system. Based on this analysis, a novel approach was developed to determine optimal settings for the pressure switch, flow switch, and stabilizer pump unit, calibrated explicitly to the municipal water pressure thresholds at each station. Findings highlighted the necessity of employing highpressure stabilization due to the influence of municipal water pressure on the pressure switch. Additionally, it was noted that the interplay between pressure and flow switches is crucial under varying operational conditions, necessitating their complementary roles in enabling automatic pump start functionality to enhance reliability. Adjustments were recommended for the logical relationship between the flow switch activation threshold and the stabilizer pump unit settings in different pump room configurations. This adjustment aimed to prevent inadvertent pump startups triggered by fire pipe network leaks, thereby addressing concerns related to overly prolonged or rapid pump activation. These research outcomes are essential guidelines for designing new subway lines' fire hydrant water supply systems and fire pump rooms. Their application ensures smooth automatic initiation of station fire water supply systems, effectively enhancing efficiency and safety across subway network fire protection systems.

This study investigated and analyzed the assembly attitude of prefabricated partition walls on the Shanghai Airport Link Line to ensure high assembly quality within largediameter shield tunnels. Initially, the coordinate system of the partition walls was established. Subsequently, the study examined the assembly attitude under initial assembly errors and errorfree scenarios. It focused on obtaining precise attitude information and the analytical expression of the partition wall's bottom plane equation for each operational condition. The analytical results reveal the following: 1) In scenarios where there are no initial assembly errors or where errors are limited to translation or rotation, the selection of control points and jacking sequences within the regulating system does not affect the assembly quality of the partition walls. The assembly attitude can be effectively managed using the derived expression for the wall's attitude. 2) When initial assembly errors extend beyond simple translation or rotation, precise control of the partition wall's attitude becomes crucial. This involves adjusting the jacking sequences within the regulating system accordingly. Utilizing the obtained expression allows for improved assembly accuracy of the partition walls. 3) The study successfully applied an analytical formula to constructing partition walls, demonstrating favorable engineering outcomes in practical applications.

Urban rail transit dispatching and command work involve complex system engineering, and the emergency dispatching and command system, as the top priority of urban rail transit dispatching and command work, directly affects the level of enterprise operation services and train operation safety. The emergency dispatch and command system is a paramount component within this framework. Using the Tianjin Metro emergency dispatch as a case study, this research first outlines the foundational modes of emergency dispatch and command used in domestic urban rail transit. It also integrates current trends in information integration and intelligent operations within urban rail transit. The study then delineates the objectives and functional requirements specific to the Tianjin Metro emergency dispatch and command platform. It proposes an architecture comprising several key layers: infrastructure, data resources, application support, application software, information display, regulatory standards, and security systems. This structured approach ensures comprehensive coverage of operational needs and regulatory compliance. Furthermore, leveraging technologies such as cloud computing and big data, we explored the technical scheme and implementation plan of the Tianjin Metro emergency dispatch command platform for the integration demand and intelligent trend. The research results can provide decision support for the safe and orderly operation and dispatch of subways under networked conditions.

This paper proposes an automated method for generating parametric BIM pipe fittings to tackle the complexity of urban rail transit pipelines and reduce the reliance on manual intervention for generating 3D models. The method addresses the challenge of accurately determining the start and end coordinates of pipelines due to irregularities during the drawing stage. The proposed approach employs spatial vector operations to automatically identify the types of fittings (such as elbows, tees, and crosses) required between two, three, and four pipelines based on the centerline coordinates of straight pipes. It then calculates the shape and positional parameters of these fittings by referencing standard dimension tables. The model is expressed using industry foundation classes (IFC), and the implementation leverages the C++ language to achieve the automatic generation of models. Verification of the method demonstrates significant improvements in efficiency and automation in the generation of piping models.

The concept of speed efficiency was proposed to measure the travel speed efficiency of urban rail transit lines. This study analyzed the operating data of 170 urban rail transit lines in China, including fully closedoperated subway, light rail, and monorail systems, considering only the train operating mode at station stops. The analysis covered various factors such as average station spacing, line design speed, and travel speed. The results showed that most lines (approximately 64%) have a design speed of 80 km/h, with average station spacing ranging from 1.0 to 2.5 km. Among these lines, about 90% have a travel speed between 30 and 40 km/h, with speed efficiency distributed between 37.5% and 50.0%. Additionally, the study quantitatively analyzed the relationships between travel speed, average station spacing, and design speed, finding both positive and negative correlations. Finally, based on fitted travel speed and speed efficiency formulas and actual data, the corresponding distribution relationships of average station spacing, design speed, travel speed, and speed efficiency were calculated. These findings provide a reference for determining a reasonable travel speed range and speed efficiency for urban rail transit lines.