This study uses multisource big data (e.g., metro card transactions, mobile phone signaling, and points of interest (POIs)) and interpretable machine learning methods (integrating random forest and Shapley additive explanations (SHAP) models) to investigate the nonlinear relationship between stationarea built environments and Chengdu Metro ridership as well as the synergistic effects among built environment variables. The results indicate that the three most important built environment determinants of metro ridership are the floor area ratio, employment density, and road density. Moreover, the SHAP model results reveal the threshold and synergistic effects of the stationarea built environment variables on metro ridership. These findings provide theoretical support and policy insights for transitoriented developmental (TOD) planning and practice.

In response to the relevant issues of urban operation transformation of existing railways under the background of "four network integration," this paper investigates new ideas and models for urban operation transformation of existing railways, taking the Xi'anHuyi railway transformation as an example. First, based on the function of urban railways, this study assessed the construction models and operational characteristics of existing railways for operating urban trains and identified current problems, such as incomplete technical standards, a low degree of network integration, a low passenger flow intensity, and significant operational losses. Second, taking the operation of urban trains on the Xi'anHuyi railway as an example, this study analyzed the transportation organization mode, passenger flow characteristics, and transportation connection methods and explored the applicability of the mixed passenger and freight modes of singletrack urban railways. Finally, this paper proposes optimization strategies for the highquality development of urban railways, including coordinating preliminary planning, optimizing transportation connections, improving operational efficiency, accelerating land development, and overcoming management barriers. These suggestions can provide a reference for subsequent renovation and upgrading of existing railways.

Urban rapid transit emerges under the background of the development of the urban circle in China. This study uses the Jingxiong Express Line as an example to explore design standards for urban rapid transit stations that can be popularized. Such stations should have the advantages of both railway and urban rail as well as integrate with urban spatial patterns and urban comprehensive transportation systems. In this study, the characteristics and differences between traditional and urban rail stations are determined. Then, the study analyzes the functional positioning of each station of the Jingxiong Express Line, which is divided

Considering the drawbacks of inconsistent building information modeling (BIM) methods and nonstandard information in rail transit engineering, it is difficult to effectively and uniformly use BIM model data. Therefore, the Industry Foundation Classes (IFC)based BIM component standard library for rail transit engineering was studied. First, the component types, IFC expression of component information, and IFCbased extensibility mechanisms were studied according to the expression requirements of rail transit engineering components. Second, the technology framework of the BIM component standard library for rail transit engineering was proposed, including basic, technical, application, and user layers. Third, the classification and code method in the national standard was used to define the classification and code of these BIM components, and a component information template was proposed to define the component properties and their resource links. Finally, encryption and decryption methods for the BIM component model were applied to ensure the security of the BIM model data. The results showed that the proposed unified BIM component library enabled project participants to use standardized BIM component models to create a project model for rail transit engineering, ensuring the standardization of BIM models.

To address uncertainties in future operational carbon emissions and carbon reduction targets for urban rail transit networks, this study analyzes operational energy consumption data for the Xi'an urban rail transit system from 2018 to 2022. The carbon emission factor method is employed to calculate operational carbon emissions for the past five years. The index method is then used to predict energy consumption and carbon emissions for the next five years. Based on the binding energy intensity requirements outlined in China's Action Plan for Green Urban Rail Development, we quantitatively analyze the total energy saving target for Xi'an's urban rail transit operations over the next five years. Subsequently, the total carbon emission constraint and carbon reduction target are determined. The research results indicate that approximately 175.9×10⁴ tCO2e of total carbon emissions were generated during the operation of the Xi'an urban rail transit system from 2018 to 2022. Under these conditions, it is expected that approximately 321.6×10⁴ tCO2e of total carbon emissions will be generated over the next five years of operations, with traction and station power consumption being the main sources of carbon emissions. If the comprehensive energy intensity reduction target proposed by the association is achieved, compared with the predicted carbon emissions, the carbon emissions of the entire network are expected to reduce by approximately 13% by 2025; the carbon emissions of the entire network are expected to reduce by approximately 15% by 2027; and in total, carbon emissions are expected to reduce by approximately 10% over the next five years.

Subway traction energy consumption can be reduced by optimizing subway timetables. To solve the problem of the impact of passenger flow fluctuations and train delays on the actual energysaving rate, this study proposes a Dueling Deep Q Network (DQN) deep reinforcement learning timetable optimization algorithm combined with a realtime subway power supply current flow calculation model. An interval iterative optimization model based on the spatiotemporal distribution of the dynamic passenger flow was established to suppress the impact of passenger flow variation. The Adaptive Moment Estimation (Adam) and root mean square propagation (RMSProp) methods were applied to predict the Qnetwork and target Qnetwork as well as improve the convergence speed of the model. While minimizing passenger transfer, waiting, and total travel times, this model allows for the seamless switching of energysaving timetables. The test results for Suzhou Line 4 demonstrate the effectiveness of the proposed method. Under the conditions that the arrival time deviation at transfer stations was less than 2 s and the overall operating time of trains remained unchanged, the traction energy saving was 5.27%, and the train kilometer energy consumption decreased by 4.99%.

The operating mileage and total energy consumption of urban rail transit systems are constantly increasing. To accurately calculate energy consumption, the actual trainside energy consumption formula that considers dynamic motor efficiency and an energy consumption simulation and calculation model based on the singleand multiplemasspoint models of train operation are constructed in this study. First, the energy flow process of the train traction drive system was studied, and the relationship between the efficiency of each component and the train operation state was established. Second, the actual train energy consumption calculation based on electric power was deduced according to the twotable method by combining the efficiency conversion of each component. The factors affecting energy consumption were comprehensively analyzed, and an energy consumption simulation and calculation method considering singleand multimasspoint train models was proposed. Finally, taking the four stations and three intervals of a regional line in China as an example, the results show that the operation energy consumption under either the singleor the multiplemasspoint train operation model achieves a deviation of less than 5% compared with the actual energy consumption, which verifies the accuracy of the proposed energy consumption model. In addition, the operational energy consumption of the multimass model was further reduced by a 1.66% deviation from that of the singlemass model. The proposed model provides theoretical support for the optimization of train energy savings and actively contributes to the development strategy of China's green economy.

In the rapid development phase of urban rail transit, issues such as inadequate emergency response and insufficient emergency handling in unexpected events are addressed. This study presents the design of a digital intelligencebased subway safety and emergency assurance system. The design architecture, application scenarios, functionalities, and key technologies of the system are elaborated. This system integrates diverse sources of data, including hydrological, meteorological, and sensor data, and utilizes emerging technologies, such as digital twins, GIS, and BIM. This system manages the entire emergency process of subway operations, including daily safety monitoring, emergency resource management, emergency plan administration, commands, and dispatch. Moreover, it focuses on enhancing capabilities for dealing with three major emergency scenarios: fires, flood prevention, and high passenger flow. This comprehensive development significantly enhances accident prevention, emergency response, and handling efficiency while elevating the levels of digitization and intelligence in the existing emergency management system.

The rail transit Passenger Information System (PIS) utilizes communication and multimedia technology and provides passengers with allround and multiscene information service systems based on a variety of display terminals. To address the drawbacks of the current rail transit Passenger Information System, such as overinvestment in hardware, low deployment and debugging efficiency, long broadcast control transmission link, and poor reliability, this paper proposes a cloud broadcast control technology architecture for the new generation Passenger Information System, which is "system into the cloud and broadcast control into the screen, " and describes in detail the technical advantages brought by the cloud playcontrol architecture through reforming the traditional audio and video transmission modes. The problem regarding picture synchronization on a multidisplay terminal was analyzed. The results show that the cloud playcontrol technology reduces the fault nodes by 50%, improves the deployment and debugging efficiency, achieves intensive construction, and can provide application support for various personalized scenarios f throughout the entire process of passenger travel from arrival to departure, which can provide reference for the subsequent construction of passenger information systems.

Given that the departure capacity of depots has gradually hindered the improvement of the operation level of the main line during morning peak hours, some cities have begun to explore the construction of ATC depots. However, existing calculation methods for vehicle sending and receiving capacity cannot be applied to ATC depots. The throat area capacity calculation method of ATC depots is investigated to compensate for the above shortcomings. First, under the ATC lightsoff mode, the minimum total train departure time is obtained by comparing the total train departure times under different train departure sequences. Second, the maximum throat area passing capacity of the ATC depot is calculated. Finally, using the Guangzhou Luogang depot as a case study, a validation study of the effectiveness of the calculation model of the throat area passing capacity under the ATC lightsoff mode is carried out. The results show that the passing capacities of the throat area under the ATC lightsoff, ATC lighting, train adjustment combination, and train approach modes are 28, 17, 13, and 11 trains/h, respectively; the ATC lightsoff mode has a greater capacity than the other three modes and can better meet the operational demand of the mainline during morning peak hours. The results of this study can serve as a reference for evaluating depot design schemes.

This study investigates the reasonable setting of suburban railway curve superelevations in the case of related specifications and standards that are not unified. The principle of prioritizing the allowable values of each superelevation is not clear. By comparing and analyzing the requirements for curve superelevation settings in different codes and by analyzing examples, this paper proposes the maximum and minimum values of design superelevation, the general allowable values for undersuperelevation, oversuperelevation, and difficult situations, and the allowable values for the superelevation slope ratio, taking into account the Code for Design of Railway Track, Code for Design of Suburban Railway, and other industry standards. The priority of design principles of allowable values for different superelevations is obtained, providing guidance for the setting of curve superelevations for new suburban railways and providing a reference for the improvement of industryrelated standards.

Synthetic sleepers of fiberreinforced polyurethane foam were initially applied in urban railway traffic to adapt to the linear induction motor system, and they have been developed into national and heavyhaul railways in recent years. Synthetic sleepers have been widely researched and applied nationwide owing to their excellent overall performance. The technological development history and standards of synthetic sleepers in China were analyzed and compared with foreign and ISO standards. In addition, the application progress, application problems, and solutions were investigated. Suggestions for the development and prospects of polyurethane synthetic sleepers in China were proposed by combining the requirements of domestic rail traffic with the application problems of synthetic sleepers.

The complexity of deepexcavation construction arises from the influence of various potential risk factors on the construction procedure. To address this issue, this study introduces an intuitionistic fuzzy TOPSIS method aimed at identifying potential highrisk factors. Initially, potential risk factors were determined through an analysis of the failure modes derived from prior excavation accidents, insights from practical engineering projects, and the expertise of engineering professionals. Subsequently, a risk evaluation hierarchy was established, and weights were assigned to experts and criteria using intuitionistic fuzzy numbers. A practical project involving a deep excavation was conducted to validate the feasibility of the proposed method. The results indicate that the TOPSIS method effectively identified highrisk factors. The developed method serves as a valuable decisionmaking tool for the safety risk analysis and control of excavation construction in similar engineering projects.

Traditional steel struts cannot be tensioned, and the construction of concrete struts is complex and generates considerable construction waste during the demolition phase. Therefore, prestressed steel struts capable against tensile and compressive stresses have been invented. The performance evaluation results of mechanics, construction adaptability, and cost with a prestressed steel strut capable against tensile and compressive stresses show that its compression bearing capacity is the same as that of a traditional steel strut and equivalent to that of a concrete strut. Furthermore, its tensile and strut stiffness performances are equivalent to those of a concrete strut and superior to those of a traditional steel strut. Its construction convenience is equivalent to that of a traditional steel strut and 20%30% lower than that of a concrete strut. The first concrete strut replaced by a prestressed steel strut capable against tensile and compressive stresses for metro excavations can not only ensure technical performance but also result in better economic and social benefits.

To explore the stress and deformation characteristics of an existing tunnel caused by foundation pit dewatering, a threedimensional numerical model was established based on an actual project. Taking the maximum vertical displacement of the tunnel as the evaluation index, an orthogonal table is used to screen the optimal combination and the main influencing factors. Then, the main influencing factors are analyzed via univariate analysis to study the stress and deformation law of the tunnel. The results of the range and variance analyses showed that the insertion depth of the diaphragm wall was the main factor affecting the maximum vertical displacement of the tunnel outside the pit. Therefore, when a new foundation pit project adjacent to an existing tunnel has a dewatering demand, this factor can be selected first to control tunnel deformation. As the insertion depth of the diaphragm wall increases, the bending moment and deformation of the tunnel decrease. After the insertion depth of the diaphragm wall reaches a soil layer with poor water permeability, the tunnel deformation decreases significantly. At this time, the deformation of the tunnel can be effectively controlled; however, controlling the deformation of the tunnel by increasing the insertion depth is of little significance. The dewatering causes the adjacent tunnel outside the pit to produce "horizontal duck egg" settlement deformation toward the pit, obliquely downward, and the deformation of the tunnel vault and the side arch waist of the adjacent foundation pit should be emphasized during the construction process.

To explore the influence of a cavity on a shield tunnel, a refined numerical model of a shield tunnel, considering ring and longitudinal joints, is established. The variation law of the internal force, deformation, and section safety factor of the segment are investigated under various conditions, such as the depth, area, and location of the cavity. Additionally, the influence of different assembly points of the segment on a tunnel with a cavity behind it is discussed. The results indicate that the order of the adverse effects of cavities at different positions behind the tunnel on structural safety is tunnel waist > tunnel bottom > tunnel top. When the cavity area is 5.0 m², with an increase in the cavity depth, the bending moment and safety factor of the tunnel section at the center of the tunnel top or bottom cavity first decrease and then increase in the opposite direction, and the ellipticity of the segment first decreases to 0 and then increases in the opposite direction. The bending moment is reversed when the cavity depth was 0.3 m or 0.2 m. The safety factor of the section at the center of the left tunnel waist cavity decreases continuously, and the ellipticity of the duct piece and the bending moment increase significantly. When the cavity depth is 0.5 m, the bending moment of the tunnel section at the center of the cavity at the top or bottom of the tunnel is reversed when the cavity area is 3.75 m². The existence of circumferential joints within the cavity reduces the internal force of the tunnel section at the center of the cavity and improves its safety factor. However, its maximum joint opening is 2.03.5 times that of a cavity without a joint. The results provide a reference for the safety evaluation of the cavity behind the lining of a shield tunnel and the selection of assembly points.

To address the problems of “insufficient maintenance” and “excessive maintenance" in existing maintenance modes, a health status grading evaluation method for subway power supply equipment that considers the importance of indicators is proposed. First, the equipment health value was solved according to a combination of an analytic hierarchy process and fuzzy statistics. The importance of the index was considered, and the health status of the equipment was graded. Finally, a drytype transformer was considered for analysis. The results show that the obtained results can reasonably characterize the health status of the subway power supply equipment, which is consistent with the actual situation, and verify the accuracy and feasibility of the method.

This study proposes a solution involving the use of a longitudinally induced ventilation system to solve ventilation challenges in factory buildings within a covered metro vehicle base, where natural ventilation is impractical and traditional horizontal ventilation systems are difficult to implement. We first created a threedimensional model for the longitudinally induced ventilation system, analyzed the impacts of the induced jet fan installation spacing and height on the airflow within the factory building based on numerical simulation results, and validated the proposed system against actual engineering conditions. The results indicate that the best overall and workstation ventilation effects can be achieved with installation spacings of 20 and 25 m, respectively, along with heights of 8 and 6 m, respectively, for the induced jet fans inside the factory building. The field tests agreed well with the simulation results. This study provides a theoretical basis for the application of longitudinal ventilation systems in engineering applications.

Studying the distribution characteristics and mechanisms of urban rail transit accidents is important for ensuring operational safety and formulating safety control measures. This study statistically analyzes 425 local and international urban rail transit operation accidents from 1970 to 2022 and compares and analyzes the causes and time distribution characteristics of operation accidents. Based on the cause mechanism and principal component analysis method, a safety evaluation system for urban rail transit operations was constructed, and a combined weight evaluation method based on game theory was proposed. Taking the data of 274 operational accidents in China from 1990 to 2022 as an example, combined with expert scoring, the safety status of urban rail transit operations in China was analyzed from a macro perspective. The results indicated that the factors causing operational accidents included personnel, equipment, and environmental factors. Among them, domestic and foreign operational accidents caused by equipment accounted for the highest proportion of accidents, accounting for 56% and 65% respectively. January, March, July, August, and December were the months with frequent accidents, which were the same as the peak months of passenger flow. The combination weighting method not only considers the amount of information in objective statistical data but also combines the experience accumulation of subjective experts, which makes the evaluation results closer to the actual operation situation and proves the feasibility of the evaluation method.

Aiming at the optimization problem of lasttrain connection planning in urban rail transit networks, which often brings difficulties in successful transfers, this study selects the arrival times of the last trains as decision variables and constructs a mixedinteger linear programming model to minimize the number of failed passenger transfers. To address the high model complexity caused by the expansion of the network scale, a quantum computing method is adopted to solve the proposed model. First, the original model is reconstructed into a twostage problem with a smaller computation scale. Then, the firststage optimization model is transformed into a quadratic unconstrained binary optimization (QUBO) model that can run on a quantum computer. Algorithm development and experimental testing are conducted based on the optical quantum computing technology of the coherent Ising machine. To verify the effectiveness of the proposed method, we consider the Beijing subway network as an example. The quantum computing results are compared with those from commercial solvers, confirming the feasibility of both the model transformation method and the quantum computing approach proposed in this study. These findings provide technical support for the further application of quantum computing in solving complex optimization problems in rail transit.