In the overall structure of a shield tunnel, the joint of the pipe segments is the weakest part of the waterproofing system, and its waterproofing performance directly influences the stability and service life of the entire tunnel. With continuous innovation and changes in structural design and construction methods, the occurrence of water leakage or sealing gasket damage at the joints of pipe segments has become increasingly severe. Therefore, research and optimization of waterproofing performance are crucial. This study begins with the waterproof principle of elastic sealing gaskets and deeply analyzes the factors that affect joint leakage, based on which specific optimization measures were proposed for the waterproof performance of pipe joints. Finally, to verify the actual effectiveness of these optimization measures, empirical research was conducted on a new type of shield tunnel project in Jiangxinzhou, Nanjing. The main conclusions of the study are as follows: the physical properties and durability of EPDM gaskets must strictly comply with regulatory requirements; The adhesive work of the onsite sealing gasket and the tensile deformation of the onsite pipe segment assembly on the sealing gasket is essential factors impacting the leakage of water at the joint; The solid section structure at the corner of a largediameter high water pressure shield tunnel requires to be optimized to avoid issues such as corner accumulation and stress concentration caused by the crosssectional size of the sealing gasket; The monitoring results after the tunnel is completed indicate that the optimized shield tunnel not only has good forming quality but also has a much better waterproof effect than traditional shield tunnels. This study not only provides a theoretical basis and practical guidance for the waterproof design of shield tunnel segment joints but also provides a valuable reference and inspiration for similar projects.

The government of Macau is actively promoting rail transportation planning and construction to enhance the capacity of urban transportation systems, promote sustainable transportation development, achieve green development goals, and provide reliable travel options for both Macau residents and tourists. This study analyzes the current state of rail construction development in Macau and summarizes key experiences in rail transport planning. These include supporting the urban pattern, enhancing traffic capacity, optimizing traffic structure, and aligning with public preferences. Additionally, the study outlines technical strategies for deployment, such as serving main corridors, connecting key hubs, integrating multiple modes, and coordinating spatial relationships, thus providing a reference for other cities in rail transport development.

To provide a theoretical basis and reference for crack control during construction, this study first monitored the construction of side walls by embedding temperature and stress sensors. The measured data were then compared with the Midas civil finite element model, the law for a temperature field, and the stress field during the construction of the side walls. The field monitoring and numerical analysis showed that the hydration heat reaction of the concrete in the early stage was relatively fast, reaching its maximum value only 20 h after pouring. The temperature was high in summer, and the cooling rate was relatively slow at approximately 0.40 °C/h. However, the cooling rate of the middle layer was relatively fast. The time at which the compressive stress reached its maximum value was close to that at which the temperature reached its maximum value. Subsequently, it entered the shrinkage deformation stage. After the critical condition of zero stress occurred, the tensile stress gradually increased with a continuous decrease in temperature, and the tensile stress at each measuring point tended to be stable 50 h after pouring. The finite element model results were close to the field monitoring data. Thus, it could play a role in the prediction of and theoretical basis for fractures. It could also be used as a reference for actual fracture control in engineering.

Surface defect detection technology plays an essential role in railway inspections by effectively preventing railway accidents and ensuring operational safety. This study addresses the issues of poor detection accuracy and low sensitivity to small targets in existing railway defect detection technologies. For the mask regionbased convolutional neural network (Mask RCNN) algorithm model, a model improvement scheme was proposed by incorporating an attention mechanism. This scheme introduces a Channelwise Spatial Module (CSM) into the feature extraction network for segmentation defect detection, effectively eliminating interference, obtaining multiscale feature representations, and acquiring more spatial and shallow information, thereby enhancing the edge detection capability for surface defects on railway tracks. In the same experimental environment, compared with the Mask RCNN algorithm, after adding the CSM, the mAP value of the Mask RCNN model increased by 6.5%. Among them, the AP values for the recognition of "depression,” “crack,” and “fatigue wear" defects on railway tracks increased by 6.3%, 6.9%, and 6.1%, respectively. The horizontal segmentation effects of the three defects improved by 11.6%, 12.5%, and 12.9%, respectively, compared with the Faster RCNN model, and the segmentation effects of the three defects enhanced by 8.8%, 10.0%, and 10.3%, respectively. This study demonstrates that the Mask RCNN model with CSM can better recognize three types of defects, enhance the detection accuracy and sensitivity to small targets, provide more secure and robust technical support, and guarantee intelligent track inspection.

To address the issue of reduced comfort resulting from rapid aerodynamic pressure changes inside the tunnels used for urban rapid transit trains, a study was conducted on the effects of the tunnel diameter and pressurerelief schemes on incar pressure. First, pressure comfort standards were selected based on relevant regulations, and a finite element model was established, which included a train model, a tunnel model, and pressure relief measures at the tunnel entrance. Subsequently, the pressure variations inside and outside of a train were investigated for different tunnel diameters and airtightness indices. Finally, the impact of implementing buffering schemes at the tunnel entrance on the incar pressure was analyzed. The research results indicated that when the tunnel diameter increased from 6.0 m to 6.1 m, the maximum incar pressure variation decreased by approximately 4.2%, with further increases in tunnel diameter having a limited effect on reducing the pressure variation. When the airtightness index was ≤6 s, each additional second resulted in a 15–25% reduction in the maximum incar pressure variation. Additionally, when a fully enclosed sound barrier was installed at the tunnel entrance as a pressurerelief structure, the maximum incar pressure variation could be reduced by approximately 4050%. Measures can be taken to enhance the overall vehicle airtightness, such as improving the seals around the doors for the driver's cab and passenger cars, installing pressure protection valves at freshair inlets and exhaust outlets, and enhancing the seals on the vehicle body and intercarriage passageways.

Subway carriages are ventilated from the outside world through fans, which regulate the temperature, humidity, and wind speed of the internal environment of the carriages, improve air quality, and enhance the thermal comfort of passengers. Due to the limited number of applicable thermal comfort evaluation indices, accurately determining the thermal comfort of subway car occupants in transient environments is challenging. This paper first focuses on occupants of a Btype subway compartment as the research subject and proposes the joint application of DRBerkeley thermal comfort evaluation indexes by considering both airflow comfort and heat sensation. The study then employs the Stolwijk physiological model of human thermal regulation to construct a threedimensional model of the amplitudeflow fan and an overall simulation model of the subway compartment. Finally, using CFD software, STARCCM+, the study analyzes the effects of different fan speeds, fan hood disturbance speeds, and fan air supply temperatures on the microenvironment and thermal comfort of the occupants under seven different conditions during the summer. The results show that the DRBerkeley thermal comfort evaluation indexes can reasonably evaluate the thermal comfort of subway compartments under the premise of meeting the airflow comfort in summer; increasing the fan speed, reducing the hood disturbance speed, and reducing the fan air supply temperature can improve the thermal comfort of the occupants; in the seven working conditions, the fan speed of 1,400 rpm, the hood disturbance speed of 3.25 rpm, and the air supply temperature of 20°C have a uniform temperature and speed distribution in the compartments. The temperature and velocity distributions in the cabin were uniform, the occupant microenvironmental heat flow field was optimal, and thermal comfort was 0.766. This method can solve the occupant thermal comfort problem more comprehensively, which is of some reference significance for optimizing the thermal flow field environment in subway compartments and upgrading occupant thermal comfort.

This study aims to enhance the safety management capabilities of urban rail transit operators by designing and implementing an intelligent safety management platform, which has been validated in practice on Urumqi Metro Line 1. Centered around a dual prevention mechanism, the platform integrates 10 functional modules to achieve risk prediction and early warning, comprehensive safety assessment, safety supervision and inspection, as well as emergency decisionmaking support and resource sharing. The analysis results are presented on the platform interface in a visually graphic format, thereby increasing the efficiency of safety production management. The findings of this research can serve as a reference for the digital transformation of safety management in other urban rail transit enterprises.

To address the problems of dynamic failure and different services in the reliability analysis of an LTEM (Long Term Evolution for Machines) trainground radio communication system, this study evaluated the reliability of an LTEM trainground radio communication system based on a dynamic Bayesian network (DBN). First, the reliability block diagram, which was constructed by analyzing the LTEM system structure and function, was transformed into a DBN, and the DBN structure and parameter modeling were conducted. Subsequently, the reliability of the LTEM system was obtained and compared based on the forward inference of the DBN. Finally, based on the backward inference of the DBN, the weaknesses of the LTEM system were recognized as a reference for operation and maintenance. The results indicate that while the LTEM system is highly reliable, the building baseband unit and train access unit are vulnerabilities that require attention.

When a traffic system is abnormal, passengers are prone to blindness, panic, conformity, and other psychological problems. They may thus make incomplete rational decisions. The Multinominal Logit (MNL) model is based on the assumptions of complete information and rationality. It has poor adaptability when used for abnormal situations. Therefore, the incomplete rationality of passengers under abnormal conditions was described using the cumulative prospect theory, and individual differences among passengers were considered to resolve this inability of the classical MNL model. First, the four factors of time, cost, comfort, and convenience were comprehensively considered, and a model was constructed of rail transit nonnormal passenger travel mode selection based on the cumulative prospect theory. It was used to characterize the incomplete rationality of passengers. Afterward, a questionnaire survey was conducted to calibrate the model parameters. Based on the survey results, a differentiated reference point following a Poisson distribution was obtained to describe the reference point dependency phenomenon of the model. The results of a case study indicated that the Poisson distribution test values with the introduction of differentiated reference points met the test criterion of a value that was greater than or equal to 0.05. It explained the essence of passengers' different decisionmaking results and presented a trend of comprehensive prospects fluctuating with the reference points. Finally, this model was compared with the MNL model to verify the rationality of the model. The research results indicated that the model focused on abnormal situations and reflected the incomplete rationality and individual differences of passengers. The overall accuracy was higher than that of the MNL model, and the average absolute error was reduced by 4.9%. The accuracy of the microscopic calculation results was 25.4% better than that of the MNL model. This could provide theoretical support for traffic demand prediction under abnormal rail transit conditions.

The conventional subway line design method cannot address the issues of a large amount of demolition, complex construction, high risk, and high cost in the densely built areas under construction. This article innovates a line design method that combines a special scissors crossover with a curved islandtype misaligned platform, which not only meets the design needs of related disciplines such as architecture, structure, signal, track, train operation, and line but also allows subway lines to avoid dense buildings around the station flexibly. The results indicate that this innovative route design method can reduce demolition, increase construction clearance, reduce open excavation scale, reduce construction difficulty and risk, and reduce engineering investments. It provides technical guidance for areas with dense buildings, as well as demolition and construction difficulties around subway stations. The application to practical engineering cases demonstrates that this innovative line design method can yield economic, technical, and social benefits.