A switch machine is a core equipment of a signal system with the largest maintenance volume, strongest maintenance difficulty, and a wide range of equipment failures. With the increase in intelligent operation and maintenance research in the urban rail transit industry, research on intelligent operation and maintenance of switch machines has attracted the interest of industry scholars. It is the foundation for achieving intelligent maintenance of urban rail signals and intelligent operation and maintenance production organization modes. This article summarizes the limitations of traditional microcomputer monitoring systems and proposes an intelligent system based on the maintenance difficulties and pain points of switch machines in the industry. The system includes critical state perception, intelligent fault diagnosis, critical state warning, and health assessment, and proposes specific implementation methods. The system was successfully applied to Nanning Metro Lines 4 and 5, and significant benefits were obtained.

This study investigates the wheelrail noise characteristics of urban rail trains passing through longspan bridges, focusing on the Dongshuimen Bridge of the Chongqing Rail Transit Line 6 and the Chaotianmen Bridge of the Chongqing Rail Transit Loop Line. Noise measurement data were collected for trains passing over the bridges. This study analyzed and compared the spectral characteristics of noise, summarizing the relevant patterns. The results indicate that the wheelrail noise generated by rail trains on largespan bridges exhibits a widefrequency characteristic, with the sound pressure level spectrum curve showing a “high in the middle, low on both sides" pattern. The noise peak of steel truss arch bridges is concentrated at approximately 800 Hz, and the structural noise generates a relative peak in the range of 6380 Hz. In contrast, the noise peak of the steel truss girder cablestayed bridges is in a higher frequency range. The threespan continuous steel truss suspension arch bridge exhibits a wide and highamplitude noise spectrum, with its noise being significantly greater than that of the steel truss girder cablestayed bridge, particularly in the midto highfrequency range of wheelrail noise.

The mechanical behaviors of Ushaped girders in urban rail transit differ in the spanning and transverse directions, and a dynamic coefficient of 1.40 in the current design code will result in material waste. Considering the bidirectional stressing characteristics, the Ushaped girder of the Nanjing Subway Line S6 Urban Rail Transit was selected as a case study, and a trainbridge coupling dynamic model was established. The effectiveness of the model was verified by comparing the test and calculated results. The dynamic coefficients of the different responses were analyzed by changing the train speed and formation. The results indicate that the girder bottom only bears longitudinal tensile stress but carries both transverse tensile and compressive stresses in the same section. The maximum dynamic coefficients of the deflection, longitudinal stress, and lateral stress were 1.231, 1.216, and 1.362, respectively, in the fulland fixedload cases of the 6car formation. When determining the dynamic coefficients of a singletrack Ushaped girder, the influence of the train formation should be considered, and the values should be distinguished according to the stressing directions. We recommend a value of 1.30 when calculating the deflection and longitudinal stress and 1.40 when calculating the lateral stress. This paper proposes reasonable values for the dynamic coefficients of Ushaped girders and provides a reference for structural optimization.

In response to the integrated fare system for areas that use crossstandard rail transit payment in urban areas, based on previous literature and domestic and international research, this article first clarifies the principle of crossstandard barrierfree ticket pricing under a single path. Subsequently, the multipath crossstandard barrierfree ticket pricing schemes are divided into two categories: origin–destination (OD) differential and OD equal pricing. The technical methods of accurately tracking passengers based on the classification of ticket types used by passengers in OD pricing research are discussed, and infeasible conclusions are obtained. The OD sameprice study recommends the weighted path algorithm, which considers the revenue of revenueguarantee enterprises and the public welfare guarantee of people's travel expenses. This paper proposes two algorithms, namely the passenger flow weighted path and average weighted path, describes the calculation steps of the algorithm in detail, and verifies the feasibility of the algorithm through two examples of Guangzhou Metro. This study is the first in China to fill a gap in the country to a certain extent.

Metro traction current changes dynamically during train operation, resulting in magneticinduced voltage in the peripheral grid circuit, which is one of the key challenges that cause transformers to undergo DC demagnetization. The generation of magnetic induction voltage is affected by various factors. To quantitatively analyze the size of the contribution of different influencing factors, this paper uses the magnetic induction voltage formula to derive the main influencing factors of the magnetic induction voltage of the subway. Subsequently, the “subway linetransmission line” magnetic coupling boundary element model is established to simulate and analyze the influence of the key factors on the induction voltage. The influence of the key factors on the induction voltage is analyzed. During the smooth running of the train, the induced voltage is not significantly affected, and at 1000 m, the induced voltage is attenuated by 90%. We constructed the backpropagation (BP) neural network to generate the magnetically induced voltage and analyzed the contribution of each influencing factor to the magnetically induced voltage using the mean impact value (MIV). The results show that the main influencing factors in the equivalent loop of the subway are the same as those in the grid, and the magnetically induced voltage in the equivalent loop is the same as that in the grid. The results show that the magnetic induction voltage in the equivalent loop is more likely to be influenced by the equivalent loop length, the contribution of which is 44.38%, and the relative distance has the smallest contribution of 21.31%. Therefore, the area of the power system constituting the equivalent loop is the most important factor affecting the magnetic induction voltage.

In order to enhance the safety of Fully Automatic Operation (FAO) systems in urban rail transit, a hazard analysis method for FAO systems is proposed, which is based on scenario fusion from the perspective of FAO system operation and maintenance. The method initiates by identifying scenario elements and integrating them, to generate FAO application scenarios. It then comprehensively selects an allocation method of semiquantitative SIL (Safety Integrity Level) among proportional allocation, prior information allocation, and combined logical allocation, to complete the allocation of safety targets of functions of the core subsystems. Finally, the analysis method is applied in an actual engineering project case, providing a reference for subsequent hazard analysis and SIL allocation for metro lines with FAO system. This approach also addresses the limitations of traditional FMECA (Failure Mode, Effect and Criticality Analysis) in performing SIL allocation for multisystem functions.

Focusing on the reuse of tunnel muck, this study aims to prepare tunnel muck from the Suzhou Metro Line 8 into a synchronous grouting material that satisfies the engineering requirements of different geological conditions by adjusting the solidification material compositions through laboratory experiments. In this project, a new doubleline shield tunnel of Metro Line 8 intersects the existing doubleline tunnel of Line 3 at Tangzhuang Station, forming a unique layout with two layers of four tracks. The muckproduced grout used in this project has a consistency value of 113 mm, and the 7and 28day strengths exceed 1 and 2.5 MPa, respectively, satisfying the engineering specifications. The deformation monitoring data show that the muckproduced grout effectively controls the impact of the upper tunnel construction on existing structures. Utilizing shield tunneling muck to prepare synchronous grouting slurry can achieve resource utilization of muck while promoting green construction and reducing construction costs by approximately 750 thousand Yuan per kilometer (double line).

Rapid urban rail transit growth presents new challenges for operation and management. Traditional methods limit data and resource utilization. China's "strong transportation country" strategy and smart city development necessitate a shift from traditional to digital thinking for subways, a crucial component of resident travel. Digitalization offers the potential to enhance operational efficiency and quality. This study analyzes the challenges of digital rail operations and presents Kunming Metro Line 4 as a case study. It explores Line 4's digital transformation journey, highlighting its economic benefits. By establishing a cloudbased comprehensive automation and business integration management system, Line 4 achieved synchronized digitalization across the enterprise, enabling practical implementation of digital metro operations. This approach reduced costs, improved efficiency, and offers valuable solutions for urban rail transit digitalization within the industry.

This study addresses problems of numerical methods for continuous media, such as the finite difference and finite element methods to simulate the discrete medium characteristics of a sandy cobble stratum. Based on the blockbased discrete element method, a discrete element model is built to simulate the process of shield tunneling through a sandy cobble stratum, and the displacement of joints and deformation of the surrounding rock and liner is studied. A finite difference model, in which a sandy cobble stratum is transformed into an equivalent continuous medium, is built to simulate the process of shield tunneling, and to compare the differences in simulation results between the discrete element model and the finite difference model. The results show that, in the discrete element model, the area at which the positive normal displacement of the joints exceeds 0.1 mm is primarily concentrated at the inverted arch, the area at which the negative normal displacement of the joints exceeds 0.1 mm is located at the hance, and the area at which the shear displacement of the joints exceeds 0.4 mm is primarily concentrated at the inverted arch. The simulation results of the discrete element method are greater than those of the finite difference method with respect to the deformation of the surrounding rock and liner; therefore, utilizing the discrete element method to verify the design of the tunnel and liner is relatively more secure and reasonable.

In response to the application problems of eCNY hardware wallets in rail transit gate boarding, business process design and ticketing system transformation methods were adopted to implement eCNY hardware wallets for the Suzhou rail transit gate boarding business. In this paper, first, the basic concept of eCNY hardware wallets is introduced, and the application forms of eCNY hardware wallets in rail transit are clarified. The current business scenario, usage needs, and technical characteristics of eCNY hardware wallets in rail transit and the overall plan for passing through gates and boarding trains with eCNY hardware wallets is determined, and a detailed design is for the registration, entry and exit, ticket processing, and other business processes of eCNY hardware wallets is described. Finally, combined with the current scenario of the Suzhou Rail Transit ticketing system, a specific transformation scheme of the Internet ticketing system and an automatic fare collection system is proposed to achieve the eCNY hardware wallet lockin service. The application of eCNY hardware wallets in Suzhou Rail Transit has a promotional significance for the promotion of eCNY hardware wallets and has a reference value for the application of eCNY in the field of rail transit.