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 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.

This study addresses the environmental vibration issues of adjacent brickconcrete structures induced by subway operations, focusing on a 7story brickconcrete building as the primary investigation subject. Vibrations were measured at the tunnel, outdoor ground level, and various structural floors to analyze the propagation characteristics along the “tunnelgroundstructure" path. The study aims to identify reasons for vibration levels exceeding standards. Key factors contributing to the issue include the shallow depth of tunnel burial, the proximity of buildings to the tunnel, and their shared soil layer, resulting in inadequate vibration attenuation through the soil. Additionally, resonance effects within specific floor slabs of the structure contribute to vibration responses surpassing evaluation standards outdoors and on the first indoor floor. A finite element model of the brickconcrete structure was constructed using measured vertical accelerations at column bases as loads. The model's accuracy was validated against measured floor responses, confirming amplification effects on middle and upper floors. Parametric analysis explored the impacts of floor count, story height, slab thickness, and wall thickness on the spatial distribution of vibration responses. The findings from this study provide valuable insights for evaluating environmental vibrations in similar structures, offering guidance for mitigating effects and ensuring compliance with vibration standards.

To address these challenges, a pragmatic design approach for the subway track panel and the substantial opening in the panel significantly reduces plate stiffness. Under construction conditions, traditional twodimensional frame section calculations fail to meet design requirements and realworld conditions. Drawing from a specific case involving the design of a stacked subway track panel in the highwaterpressure fine particle strata east of Beijing, this paper introduces the project's envelope and main structural design concepts. It examines critical structural calculation issues, consolidates design insights, and outlines operational conditions. The study yields a practical design scheme, offering valuable insights for future subway track panel designs during construction processes.

To address the challenges posed by traditional opencut methods in subway station construction, such as disruptions, shop demolitions, and relocation of underground pipelines, this study investigates the construction technology of jacking a rectangular tube for a subway station, focusing on the Haibang Station of the Guangzhou Metro Line 3 East extension project. Initially, three different combinations of pipe jacking schemes are proposed, each with unique characteristics tailored to the specific station engineering requirements. Selection among these schemes is based on practical considerations. Subsequently, the study details the section design, selection of jacking equipment, design of pipe sections, and implementation of waterproofing measures for the station. Finally, the feasibility of employing the combined pipe jacking method is validated through theoretical calculations and numerical simulations. The results demonstrate that the construction technology of jacking a rectangular tube for subway stations effectively addresses the challenges associated with underground pipeline integration. It ensures safety and feasibility in subway station construction. This approach offers a promising alternative to traditional methods, potentially minimizing disruptions and optimizing construction efficiency in urban environments.

To enhance the energy efficiency of urban rail traction powersupply systems, this study investigated various strategies aimed at reducing energy consumption. An equivalent circuit model of an urban rail transit traction power supply system was initially developed based on traditional power flow calculation methods. This model considered the nonlinear characteristics of traction energy for urban rail vehicles and variations in the equivalent circuit within a multivehicle context. Subsequently, a power flow analysis method was devised utilizing the established equivalent circuit model and node voltages. Finally, using data from Hefei rail transit line 1 and results from multitrain operation simulations, the study analyzed power, voltage, and energy consumption across different traction powersupply configurations: existing systems and three new systems integrating inverter feedback, energy storage, and photovoltaic technologies. The findings indicate significant advantages for the new systems: the system with inverter feedback notably reduces traction substation energy consumption, while the energy storage system effectively reduces peak power demands. Additionally, the system incorporating photovoltaic technology achieves a substantial 24.89% reduction in traction substation energy consumption compared to the existing setup. These results serve as a valuable reference for optimizing energy efficiency and emissions reduction efforts in urban rail transit systems, offering insights into practical strategies for enhancing operational sustainability.

In order to enhance the excavation efficiency of an EPB/TBM dualmode shield machine and minimize disc cutter wear, the study was conducted on the performance of disc cutters along the Intercity Railway from Airport East Station to Huangmabu Station, Shenzhen. The research focused on the fullsection hard rock strata from ZDK8+583.0 to ZDK8+359.8 on the left side of the tunnel. Initially, the study analyzed cutter replacement conditions and wear patterns based on different functions and types of disc cutters to determine optimal performance criteria. Subsequently, the service life of the disc cutters under optimal conditions was evaluated to guide replacement scheduling. Finally, a tool information management system tailored to the project's requirements was established. The findings highlight that China Railway's wideblade disc cutter is wellsuited for excavating this specific formation. The implemented tool management system effectively manages comprehensive information about the tools, which helps ensure costeffective and efficient onsite operations. This research serves as a practical guide for choosing disc cutters for shield tunneling machines. It promotes better information management practices for disc cutters, leading to safer and more efficient operations.

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.

Mediumand lowvolume rail transit, as a supplement to metro networks in super or mega megacities and as the backbone of large and mediumsized cities, is essential for solving urban traffic problems. Based on a survey of more than 2600 mediumand lowvolume rail transit operation lines in 496 cities in 65 countries, a database of mediumand lowvolume rail transit lines worldwide was constructed. Based on this database, 9 types of mediumand lowvolume rail transit systems (gear rail, tram, suspended monorail, automated people mover systems (APM), straddle monorails, linear motor systems, mediumand lowspeed maglev, electronic guidance rubbertired system, and beamguiding rubbertired system) have been obtained worldwide, with a total length of 18 744.84 km. And statistics were conducted on the distribution of mediumand lowvolume rail transit in various continents and countries. The results showed that it is mainly distributed in 32 countries in Europe, including Germany and Russia, with a total length of 13 256.0 km, accounting for 70.7%. Statistics show that the distribution of various rail transit systems in different countries/cities, with different urban characteristics and functional positioning of different lines shows that mediumand lowvolume rail transit systems mainly serve cities with a population of less than 3 million. 76.25% of tram lines, 47.82% of straddle monorail lines, and 42.11% of linear motor system lines are backbone lines, 84.62% of gear rail lines are tourist lines, and 70.73% of APM lines are airport dedicated lines. Additionally, the origin and development of each system are summarized, and the technical characteristics, parameters, and applicability of each system are analyzed. The results provide a reference for the selection of urban medium and lowvolume rail transit systems in China.

To improve the efficiency and accuracy of urban railtransit security inspection systems, this paper designs a novel patternrecognition mode to effectively combine artificial intelligence (AI) image recognition technology with manual centralized pattern recognition. First, based on the current liquid inspection, a liquid detection algorithm is introduced to avoid the open inspection of safe liquids. Second, security products are classified according to their risk levels. Finally, AI confidence judgment, manual sampling, or necessary inspection charts are combined to determine the pattern recognition mode, which can flexibly adjust the depth of the AI intervention according to the accuracy of the AI image recognition and the requirements for pattern recognition at different stages. With the continuous improvement in the accuracy of AI image recognition, it gradually changes from an AIassisted manualbased pattern recognition mode to an AIbased manualassisted pattern recognition mode and finally achieves a fully intelligent pattern recognition mode. A case analysis reveals that the judgment graph model can further achieve rapid security inspection, cost reduction, and efficiency increase without reducing the safety inspection level of urban rail transit stations.