To address the shortage of realtime data and the accuracy limitations of existing automatic line control systems, we propose an intelligent upgrade scheme for train control systems. First, considering the distinct characteristics of electric and air braking in train operations, we developed accurate braking models for both systems, incorporating the switch between electric and air braking. Next, we optimized the ATO controller and applied a sliding mode adaptive robust control strategy. This strategy adjusts the controller in real time, enhancing its robustness and adaptability to varying vehicle parameters and external environmental interferences. Using Beijing Metro Line 5 as a case study, we simulated the precise train braking model and the sliding mode adaptive robust controller to calculate the stopping accuracy and speed error of the train. The results demonstrate that, compared to proportionalintegralderivative (PID) control and sliding mode control, the proposed control algorithm significantly reduces parking accuracy and speed errors. Specifically, the average parking accuracy achieved is less than 8 cm.

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 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.

In response to the absence of experimental verification of smoke control and ventilation models for tunnel fires without fire doors in crosspassageways of urban rail transit projects, this study conducted a comprehensive ventilation and smoke control experiment in a typical tunnel of the Zhengzhou Metro. The experiment focused on varying locations of train fires within the tunnel. By assessing smoke control wind speeds in both the fire tunnel and crosspassageway under different conditions, our objective was to validate the impact of not installing fire doors in crosspassageways on tunnel fire ventilation and smoke control, and to evaluate the effectiveness of different ventilation and smoke control models. The results indicated that in tunnels with fully enclosed platform doors and one crosspassageway in the test sections, the absence of fire doors (i.e., with open fire doors) resulted in all tested ventilation and smoke control models achieving wind speeds exceeding 2 m/s blowing towards the side where the fire occurred at the door openings. Simultaneously, exhaust wind speeds inside the fire tunnels exceeded 2 m/s, meeting the regulatory requirements for smoke control. These findings suggest the feasibility of omitting fire doors in similar projects. Different ventilation and smoke control models demonstrated varying wind speeds at door openings. Models utilizing two tunnel fans to supply air to the fire tunnel and pressurize nonfire tunnels, coupled with four exhaust fans to extract smoke from the fire tunnel, achieved higher wind speeds at crosspassageway entrances.

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.

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.

An integrated spatial finite element model of railbridgepier was developed and validated to investigate the effect of temperature on the interaction between bridges and rails, particularly focusing on smallradius curved bridges used by trams. This study compared and analyzed the bridgerail interaction laws between straight bridges and smallradius curved bridges. It specifically examined the additional expansion force of the rail, lateral forces at the top of bridge piers, and longitudinal forces under overall and local heating conditions. Under overall heating conditions, the research found that smallradius curved bridges experience greater lateral displacement of the steel rail and higher lateral forces at the top of bridge piers compared to straight bridges. Moreover, as the bridge temperature increased, the additional expansion force of the rail also increased. Calculations using overall heating conditions resulted in larger expansion forces and longitudinal forces on the top of piers compared to local heating conditions. Based on these findings, three different fastener arrangement schemes were proposed and evaluated. It was observed that fasteners with lower resistance could effectively reduce the additional expansion force of the rail. However, insufficient longitudinal resistance might increase the risk of rail joint fractures. In conclusion, the study provides valuable insights for designing continuously welded rails on smallradius curved bridges for tram systems, offering guidance on optimizing fastener arrangements to mitigate rail expansion effects while ensuring structural integrity.

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.

This study focuses on a straightline section of a subway line to analyze the factors influencing the vibration source strength in subway tunnels. Vehicleinduced vibration signals and velocity signals were collected synchronously, and the timedomain and frequencydomain characteristics of allday test samples were statistically analyzed. The results showed that during peak hours in the morning and evening, the vibration response inside the tunnel may not be completely maximized, and the degree of dispersion of the vibration source intensity is directly related to the vehicle state. The study found an average difference of 6.7 dB in the VLZ of the tunnel wall measurement points caused by V₁ and V2 vehicles. Using more than 40 sets of test samples to calculate the vibration source intensity yielded results closer to the daily sample mean. The main frequency of tunnel vibration caused by the wheelrail system shifts with changes in vehicle speed. A strong linear positive correlation was observed between vehicle speed and the vibration acceleration levels of the track bed and tunnel wall. Specifically, for every 10 km/h increase in vehicle speed, the vibration increases by about 1.7 dB and 2.6 dB, respectively. When the speed difference is within 10 km/h, the vibration source intensity changes within 1 dB; when the speed difference is between 10~20 km/h, the increase is about 1.5~2.2 dB. The coefficient of speedcorrected CV was calculated to be 18.5, aligning closely with the coefficient used for train speed correction in the vibration prediction formula. Tunnel wall vibration was more discrete in the lowfrequency band below 40 Hz, but this band contributed minimally to the source strength of vibration, accounting for 15.29%. The dominant frequency band was 5063 Hz, contributing 59.55% to the source strength of vibration. These research findings can provide a reference for further refining the vibration prediction formula and offer a theoretical basis for improving the accuracy of metro tunnel source strength test results.