To enhance the train transportation efficiency under this system and meet the operational needs of dynamic marshalling adjustment, an online marshalling technology for urban rail train control systems based on vehicle-to-vehicle (V2V) communication is proposed, including flexible marshalling and virtual marshalling technologies. Firstly, the technical scheme and operation procedures for V2V-based virtual marshalling are established, and the core technologies under flexible marshalling are expounded, such as the setting of marshalling area parking points, determination of the vehicle-mounted control end, verification and protection of marshalling forms, collision envelope schemes, and vehicle- vehicle-mounted integration technology. Secondly, the technical scheme and operation procedures for the virtual marshalling function of V2V communication are established, and the core technologies under virtual marshalling are expounded, such as high-performance V2V communication technology, V2V communication security protection technology, collaborative control technology, multi-sensor fusion technology, etc. The results show that compared with the traditional CBTC marshalling technology, the the V2V-based marshalling technology reduces operational time by approximately 14 seconds and improves efficiency by about 34%. This study aims to provide a theoretical basis and reference for the marshalling technology operations of the next-generation train control system.

To investigate how urban express lines can achieve "rapid arrival" and enhance their service level and public transit attractiveness, this paper uses Chengdu Rail Transit Line 19 as a case study to examine key technologies in transportation organization oriented toward rapid arrival. Under Chengdu's dual-airport configuration of "one city, two airports," the Chengdu Rail Transit Line 19, which achieves "30-minute rapid connectivity between dual airports," represents an exemplary case of rapid arrival for urban express lines. Facing a 66.7 km operating distance between the two airports and a composite functional positioning, Chengdu Rail Transit Line 19 innovatively adopts the following key train operation technologies to achieve rapid inter-airport connectivity: Completing the design of a "one-line separation and three-line through operation" scheme among Lines 17, 18, and 19 to ensure the feasibility of direct train service between the two airports; increasing the maximum operating speed of the urban AC A-type trains from 140 km/h to 160 km/h, thereby creating better conditions for 30-minute direct connectivity between the dual airports; maintaining high-speed operation of direct trains by increasing their passing speed through stations to 160 km/h and introducing No. 42 turnouts. Through a systematic review of these innovative technologies, this paper identifies five key design insights for achieving rapid arrival in urban express line transportation organization: Advance planning to ensure cross-line operation capabilities; unified scheduling of cross-line operating lines; new approaches to speed enhancement for urban A-type vehicles; favorable conditions for increasing express train passing speeds; and cautious introduction of No. 42 turnouts into underground projects.

To promote the coordinated development of urban rail transit with urban spatial layout, population and employment distribution, and public service facilities, this paper constructs a multi-dimensional (public transport accessibility level, PTAL) quantification model that integrates urban rail transit and conventional bus services based on a comprehensive urban transportation model. This model is used to systematically evaluate the public transport accessibility within the Dongguan metropolitan area. The study reveals that the current PTAL level in Dongguan is generally low, with average accessibility index ratios for the central urban area, sub-centers, economically strong towns, and ordinary towns recorded at 3.6:0.8:1.2:1. This indicates a spatial pattern characterized by "single-core polarization, small-scale decentralized clusters in peripheral areas, and homogeneous fragmentation in the remaining regions." The findings highlight several issues, including a disconnect between public transport resource allocation and the polycentric structure, a lack of synergy between urban rail transit and bus services, and a mismatch between public transport resource provision and the distribution of population and employment. The research demonstrates that by establishing a network of urban rail transit express lines and strengthening public transport services in underdeveloped areas, the overall public transport accessibility in the metropolitan area could increase by 65.3%. Notably, sub-centers such as Songshan Lake and Binhaiwan could experience an improvement of up to 153.6%, significantly reinforcing the polycentric structure defined as "one primary center, two sub-centers, and six clusters." Furthermore, optimizing bus connections at urban rail transit stations and coordinating the layout of public facilities can enhance the alignment between rail transit resources and the distribution of population and public services. Ultimately, this study provides technical support for establishing an integrated "rail transit+bus" system to advance polycentric development in Dongguan.

In response to ambiguities and inconsistencies in China's evaluation standards for train-induced environmental vibrations in urban rail transit, which affect assessment conclusions, this paper adopts a combination of field measurements and statistical analysis to conduct a comparative study of current standards regarding evaluation indicators, weighting curves, analysis frequency ranges, and determination of train pass-by intervals. The main conclusions are as follows: it is recommended to establish both a time-frequency comprehensive evaluation indicator and a frequency-domain evaluation indicator. It is suggested to set the single-value evaluation indicator as the maximum vertical vibration level (VLz_max), the frequency-domain octave evaluation indicator as the maximum vibration level of 1/3 octave bands (VAL_max), and adopt the peak value retention method in the calculation. The W_k weighting curve is suggested to be adopted and the analysis frequency range is recommended as 1~80 Hz. To effectively eliminate the influence of subjective factors in determining train passing periods on evaluation results, it is recommended to use time weighting for vibration signal analysis and the peak hold method for calculating VLz_max and VAL_max.

In view of the limitations of the two-dimensional perspective of the traditional node-place model in complex urban environments, this study constructs a three-dimensional "node-place-vitality" model. With 41 stations of Jinan's rail transit as the research subjects, a service radius of 800 meters around each station is demarcated. Twenty-four indicators are selected from three dimensions: traffic function (node), urban space (place), and dynamic vitality (vitality). The comprehensive subjective-objective weighting method and K-means clustering analysis are employed to evaluate the coordination of station areas. The results indicate that the three-dimensional model can effectively uncover the synergistic relationships among nodes, places, and vitality. Moreover, the stations are classified into five types: high-vitality hub stations, vitality-improvement stations, balanced-development stations, node-reinforcement stations, and comprehensive-cultivation stations. Their spatial distribution is highly associated with the development characteristics of Jinan's main urban centers, sub-centers, and marginal areas. This research offers a scientific foundation for the optimization of Jinan's rail transit station areas and the formulation of TOD strategies. Additionally, it provides a novel perspective for studies on the coordination of station areas in similar cities.

To address the critical issue of predicting the time-series passenger flow at subway stations, a novel hybrid deep learning method, AFT-K-GRU⁺, is proposed to provide more accurate decision support for subway operation and management. Leveraging the multi-scale temporal dependencies inherent in subway passenger flow data, the model innovatively integrates three core components: the attention-free transformer (AFT), the gated recurrent unit (GRU), and the KAN network. Specifically, the AFT module captures long-term periodic patterns in passenger flow data, the GRU module focuses on extracting short-term fluctuation characteristics, and the KAN network enhances the model's expressive capacity. To enhance the robustness of the model's predictions, this study innovatively designs a knowledge-driven correction controller based on residual feedback, which enables online self-correction of the output. Experimental validation using real-world card swipe data from Beijing subway stations demonstrates that the AFT-K-GRU⁺ model effectively predicts station passenger flow, achieving mean error reductions of 25.3% and 18.7% compared to Transformer and LSTM methods, respectively. This model offers effective methodological support for subway operators, assisting management departments in passenger flow control and daily planning, thereby enhancing the operational efficiency and service quality of subway lines.

The horizontal alignment design of urban metro shield sections is prone to being constrained by dense structures and land use, which usually results in increased investment and demolition. An optimization model for dual horizontal alignments in metro shield tunnel sections is proposed, which takes the intersection points of the left line and the right line as independent variables. The specification requirements are transformed as geometric constraints, and penalty terms for land use under-passing and line spacing violations are introduced in the objective function. The model is solved by a collaborative differential evolution algorithm with separate populations for the left and right lines. The case study shows that the proposed model can optimize a 2.7 km horizontal alignment in approximately 150 seconds, reducing the total investment by approximately 0.3%. It automatically avoids control areas and guides the automatic parallel or separated design of horizontal dual lines in shield tunnel sections.

To address the high risks faced by metro systems due to their enclosed underground spaces, vulnerable facilities, and structural complexity amidst frequent rainstorm waterlogging, it is imperative to develop a scientific vulnerability assessment method for metro stations to enhance comprehensive resilience. Based on the chain analysis framework of the driver-pressure-state-response-control (DPSRC) model, this study systematically analyzes the dynamic causality of metro rainstorm waterlogging risks and constructs an assessment index system comprising 5 criterion layers and 20 indicator layers. By integrating subjective and objective weights using the AHP-entropy weight method, a comprehensive vulnerability assessment approach for metro stations was proposed and applied to an empirical analysis of 99 stations in the Ningbo Metro. The results indicate that: ① The proposed method can accurately and effectively assess station vulnerability; ② Stations vulnerabilities exhibit an asymmetric distribution across high (19.10%), medium (51.69%), and low (29.21%) vulnerability levels, with 70.79% of stations exposed to risk, highlighting an urgent need for systemic prevention and control; ③ Waterlogging prevention capacity, monitoring and early warning capabilities, and emergency equipment reserves constitute the key contributing factors to high-vulnerability stations. This research provides a reference for rainstorm waterlogging risk management, disaster prevention, mitigation planning, and resilient transportation development in urban metro systems.

In drill-and-blast tunnel construction, the geometric configuration and retained dimensions of the core soil directly influence tunnel settlement magnitude and surrounding rock stability. Traditional manual monitoring methods are inherently subjective, inefficient, and fail to meet real-time monitoring requirements. This paper proposes an automated core soil monitoring method based on an improved YOLO framework. By defining core soil feature points, a standardized annotation system is established. A lightweight detection model incorporating the Convolutional Block Attention Module (CBAM) is designed, effectively suppressing false detections caused by uneven illumination, dust interference, and blurred soil boundaries. Integrated with perspective geometry vanishing point prediction techniques, the VPTR model is employed for vanishing point detection and geometric constraints. This approach corrects perspective distortion errors in core soil cross-section shape calculation, incorporates core soil dimensions and proportions into potential risk classification criteria. For engineering deployment, knowledge distillation and dynamic precision-switching techniques are adopted to enable lightweight operation on edge computing devices, supporting the real-time decision-making demands of "monitoring while excavating".

To address the challenge of managing excessive deformation defects in operational shield tunnels in China, a comprehensive tunnel deformation correction technology system centered on the Radial Cement-Soil Pile Method for Correcting Excessive Tunnel Deformation has been developed. This system actively constructs a spatial network reinforcement body composed of horizontal, vertical, and inclined cement-soil piles in the soil outside the tunnel. It formulates an optimized construction sequence of "first constructing horizontal piles to restrict convergence, then constructing vertical piles to lift settlements, and finally constructing inclined piles to coordinate deformation" and adopts refined strategies such as graded pressure control to accurately apply correction forces. Meanwhile, based on the principle of minimum potential energy, a semi-empirical formula for predicting the single-ring lifting and convergence correction values has been derived, thereby forming a complete set of technical measures. This technology system has been applied and verified in a metro tunnel section in Northeast China. The results show that the Radial Cement-Soil Pile Method for Correcting Excessive Tunnel Deformation can synergistically correct settlement and convergence issues, effectively stabilize the post-construction settlement rate, and significantly improve leakage defects. The research results provide an innovative technical solution for the treatment of defects in operational shield tunnels and have reference value for similar engineering projects.

To investigate the dynamic impact of straddle-type viaduct construction on existing metro tunnels, this study takes the Wangsheren Station to Wangsheren North Station section of Jinan Metro Line 6 as the engineering background. Field tests and numerical simulations were conducted to systematically analyze the deformation patterns of tunnels under the multi-stage coupled effects of "pile foundation excavation, foundation pit unloading, and bridge superstructure loading." The findings reveal that: (1) Foundation pit excavation induces significant tunnel uplift (maximum 4.62 mm), accompanied by horizontal contraction (maximum 1.74 mm) and vertical expansion (maximum 3.25 mm). After bridge loading, the tunnel subsides, with horizontal expansion and vertical convergence observed. (2) The clearance between the tunnel and foundation pit significantly influences uplift deformation: as the clearance increases from 6.7 m to 20 m, the uplift decreases from 5.74 mm to 0.90 mm (approaching zero at ≥15 m), while subsidence remains stable at approximately 5.2 mm. A clearance of ≥12 m is recommended for risk mitigation. (3) Stratigraphic characteristics dominate deformation responses: silty clay layers exhibit greater uplift during excavation (+1.2 mm), whereas gravelly sand layers experience more pronounced subsidence during bridge operation (–1.5 mm). Deformations in moderately and slightly weathered rock strata are negligible. (4) Interval construction of multiple pile caps reduces subsequent excavation-induced uplift (with a 12% reduction for the second pile cap), supporting a "alternate excavation" construction strategy. Innovatively, this study proposes a deformation prediction model based on stratigraphic heterogeneity, which overcomes the limitations of traditional homogeneous assumptions and provides a theoretical foundation for optimizing the design and risk assessment of straddle-type viaduct projects.

To evaluate and mitigate risks to the structure of a metro station in a cobble stratum under rising groundwater, this study utilized the finite element method to develop a two-dimensional numerical model of a representative cross-section based on a Beijing subway station project. The model reasonably incorporates strength degradation induced by soil wetting and comprehensively examines the structural internal forces, displacements, and evolution of plastic zones within the ground in response to scenarios of groundwater level rise in gravelly deposits. The simulation results show that the base slab, roof slab and sidewalls, as the enclosure structure, all exhibit increased compressive stress on their soil-facing surfaces. The base slab and roof slab bear the horizontal stress from the sidewalls, thereby offsetting part of the mid-span bending moment and reducing the tensile stress. The intermediate slab and the central column, as intermediate supporting members, continue to perform their supporting function effectively. Notably, the slab-column and slab-wall connections are regions of stress concentration and therefore require particular attention to prevent structural cracking or damage caused by excessive stress. In a cobble stratum, both the stratum and station experience uplift, with the station's uplift marginally surpassing the surrounding soil. Structural integrity remains unscathed without local deformation, thus indicating a relatively diminished risk of localized structural harm. The plastic zone is mainly concentrated in areas such as the bottom corners of the sidewalls and does not extend to the ground surface to form a rupture zone, indicating a low probability of overall instability.

To address the problems of aging and deformation of rubber boots, unsupported sleepers and gauge variation caused by long-term operation on existing elastic short-sleeper tracks, and to improve the stability and operational safety of the track structure, this paper proposes a novel treatment technology for unsupported defects in elastic short-sleeper tracks to overcome the low construction efficiency and insufficient repair precision of existing repair methods. This technology combines a novel high-flow repair material with a refined grouting process, enabling complete filling of gaps smaller than 1 mm. Off-site grouting tests verified the feasibility of the material and construction process, and the mechanical properties of the repaired elastic short-sleeper track were evaluated based on static stiffness and fatigue tests. The test results demonstrate that this treatment method effectively fills the unsupported areas and enhances the overall stability of the track structure. It is suitable for the rapid and efficient repair of existing tracks under time and space constraints and has good potential for engineering application.

Surface loading can cause certain deformations in subway tunnels, and excessive deformation will affect the safe operation of subway tunnels. To study the influence of asymmetric surface filling on variable-section subway tunnels, a finite element model of horseshoe-shaped and box-shaped tunnel structures was established based on the road backfilling reconstruction project above the side of a certain underground section of Shijiazhuang Metro. The surface settlement and tunnel stress-deformation patterns during road backfilling construction were analyzed and compared with field monitoring results for verification. Furthermore, the effects of parameters such as tunnel burial depth, loading magnitude, and loading dimensions on the underlying variable-section tunnel were discussed. The results show that: under asymmetric filling, the surface soil displacement field approximately exhibits a "V"-shaped settlement; the maximum surface settlements in the tunnel areas of horseshoe-shaped and box-shaped sections are 15.85 mm and 27.17 mm, respectively; tunnel structural deformation is dominated by vertical settlement with relatively small horizontal deformation; compared with the horseshoe-shaped section tunnel, the box-shaped section tunnel is more significantly affected by surface loading; the deformation of the tunnel at the intersection between the horseshoe-shaped and box-shaped sections shows a certain abrupt change, and cracking and water leakage issues in this junction area require close monitoring during construction; loading magnitude and loading range are positively correlated with tunnel vertical settlement, while the horizontal distance between the loading center and tunnel axis and tunnel burial depth are negatively correlated with tunnel vertical settlement; the loading range has a significant influence on the distribution range of tunnel settlement. When the tunnel burial depth exceeds 24 m or the horizontal distance between the loading centerline and tunnel axis exceeds 50 m, surface loading has almost no effect on tunnel settlement.

Because the operating conditions of urban rail transit systems are highly variable and load fluctuations are severe, traditional energy-saving methods based on static scenarios struggle to accommodate dynamic load demands effectively. Therefore, load scenarios must be accurately identified, and an energy-saving optimization method for flexible traction power supply systems is needed to achieve dynamic "scenario-strategy" matching and improve energy-saving performance. Accordingly, an energy-saving optimization approach for urban rail transit flexible traction power supply systems considering multiple load scenarios is proposed. First, a k-Medoids load clustering method based on t-SNE is designed. A strategy of clustering after dimensionality reduction is adopted to more accurately reflect the correlations between system load and operating periods and seasons. Second, an energy-saving optimization model for the flexible traction power supply system is constructed. Based on an intelligent optimization algorithm, the virtual resistance of traction substations is adjusted to minimize the total incoming energy of the system. Through simulation validation, the effectiveness of the proposed method is verified. The proposed load clustering method effectively extracts the inherent characteristics of the load, reveals the correlation between system load and operating periods and seasons, and identifies six specific operating scenarios. The proposed energy-saving optimization method achieves good energy-saving performance in various operating scenarios, with a maximum energy-saving rate of 4.07%. The energy-saving optimization method for urban rail flexible traction power supply system based on load clustering has connected the complete chain of "scene recognition-strategy matching-dynamic adjustment", which can provide important technical support for energy-saving operation of urban rail transit.

To address the problems of high energy consumption and lagging thermal environment regulation in traditional air-conditioning systems of metro stations, this study proposes a dynamic thermal environment management system integrating nature-like wind technology with spatially gridded monitoring, CFD pre-simulation, and equipment-linked control. In the reconstruction project of Nanhu Station of Nanning Rail Transit Line 1, 45 sensors were deployed to construct a gridded monitoring network, and the layout of monitoring points and fan positions was optimized based on CFD pre-simulation. A hierarchical control strategy centered on perceived temperature was developed to realize the intelligent linkage between air conditioners and nature-like wind fans, so as to achieve the energy-saving effect of the air conditioning system. The results show that when the ambient temperature rises to 29℃, the system enhances turbulent heat dissipation (wind speed 0.8–2.5 m/s), making the perceived temperature equivalent to 27℃; the PMV value drops to 0.8–1.2 (PPD≤19%), and the comprehensive energy-saving rate in the air conditioning season reaches 32.1%. The system provides a replicable technical pathway for the green renovation of metro stations.

To address the problem of insufficient operating speed caused by step-by-step setting coordination in traditional definite-time overcurrent protection for load-switch-based medium-voltage ring networks in urban regional railways, this paper proposes a fast protection method based on differential current. The fault section is identified using the fault characteristics of differential current, and the fault information is transmitted to the master station via the GOOSE network. The master station then controls the tripping of the outgoing circuit breaker at the substation to achieve rapid fault clearance. At the same time, the outgoing current of the substation is monitored. When the outgoing current drops below the preset threshold, a command is sent via the GOOSE network to control the tripping of the load switches on both sides of the fault section, completing the fault isolation. After fault isolation, the circuit breaker at the substation outgoing line and normally open point are closed to restore power supply to the healthy area. Simulation results show that under different fault types, locations, and transition resistances, the proposed method can achieve rapid protection operation and effective fault isolation, significantly improving protection speed and providing a reliable guarantee for the safe and stable operation of the load-switch-based medium-voltage ring network in urban regional railway systems based on load switches.

Due to the large quantity of equipmentin environmental control rooms, it is necessary to optimize the equipment layout to save space while guaranteeing normal maintenance. Therefore, an automatic spatial optimization approach is proposed to optimize the layout of central chiller plants. A repulsion model is adopted to quantify the rationality of equipment layout, which was regarded as the optimization objective. The differential evolution algorithm is utilized to adjust the equipment layout within a given space for the lowest optimization objective. Moreover, this approach repeatedly reduces the given space to minimize the space occupation of the central chiller plant. A real metro station environmental control room was taken as the case to verify the effectiveness of the proposed approach. Results indicate that the proposed approach reduced the occupied area of the equipment from 105 m² to 100.1 m², with reasonable equipment spacing maintained. Therefore, the proposed approach is able to optimize equipment layout for metro station environmental control rooms, thereby achieving room space saving and reasonable equipment spacing.

The index system dominated by key performance indicators (KPIs) has problems such as siloed fragmentation among departments, alienation of incentive functions, and insufficient process supervision. In the face of the era opportunities of smart urban rail construction and high-quality development, it is necessary to explore and design a new performance index system that can better help enterprises transform their strategic vision into an executable path. The mature objectives and key results (OKR) method is proposed as the core idea of optimization design. Guided by "departmental internal-control indicators－vertical alignment indicators-horizontal coordination indicators" and following the logical chain of "goal hierarchy-task quantification–closed-loop results", the proposed system builds departmental internal-control indicators to strengthen process management, establishes strategic empowerment indicators aligned with departmental responsibilities to reinforce positive incentives, and introduces cross-departmental coordination indicators through a four-level linkage mechanism of "strategy–process–department-post." Taking Shanghai Metro as the research object, this study designs a new indicator system, including department-level and field-level lists of "strategic objectives–key results–empowerment indicators", as well as a list of cross-departmental horizontal coordination constraints. Since its trial implementation in December 2024, employees' trust in the evaluation results has steadily increased. Organizations at all levels can not only easily trace key-result implementation processes and monitor progress, but also more efficiently identify the underlying causes behind observed problems and more promptly formulate targeted improvement measures.