The maximum operating speed of urban rail expresses is 160 km/h. As the main technical parameters of the gauge in the current national standards do not cover this speed, this study uses theoretical analysis and dynamic simulation methods to research the gauge system and calculation methods. The calculation formulas in the Standard of Metro Gauges (CJJ 962003) were adjusted to be suitable for the 160km/h express project. The optimal structure gauges of the station, tunnel, and bridge were formulated in combination with the express project characteristics based on research on the basic gauge parameters. 1) Compared with the stopping condition, when the train passed the station at 100 km/h, the distance between the station platform and the central line of the track was 1,600 mm. 2) The size of the circular tunnel section was determined by the space requirement for equipment layout in the urban rail express project. When the flexible overhead contact system was used, the optimal tunnel diameter was 7.5 m (the gauge diameter was 7.2 m). When the rigid overhead contact system was used, the optimal tunnel diameter was 7.1 m (the gauge diameter was 6.8 m).

Current solutions for enhancing the efficiency of existing urban rail transit lines are limited. As a pioneering initiative, the concept of running express/local trains on these lines presents a versatile solution for Shighquality development scenarios. After systematically reviewing the methods for running express/local trains on existing lines, this paper introduces four distinct strategies tailored to the unique features and operational needs of different lines: employing extended intervals for rapid trains, implementing alternate stationskipping for accelerated service, utilizing malfunctioned train stop lines for express/local runs, and operating partialroute shuttles for express/local trains. Drawing from domestic and international case studies, this research delves into the operating principles, advantages, disadvantages, and operational requirements of the aforementioned methods. Additionally, the necessary modifications for implementing express/local train services on existing lines are discussed.

Passenger flow forecasting for the initial operation stage of a new rail transit line is fundamental for operational safety assessment and organizational preparation. This study analyzes the characteristics of forecasting work in terms of the forecasting period, research objects, basic modeling data, and forecasting models. The technical difficulties in carrying out such forecasting work are also summarized. Considering the characteristics and difficulties of forecasting, this study introduces a new forecasting framework, and the key procedures in the framework are then explained, including data collection, traffic surveys, analysis of the operational characteristics of urban transport, travel demand forecasting from macroscopic and intermediate perspectives, forecasting evaluation, and sensitivity analysis. Finally, the study also discusses main research points of forecasting work with respect to network passenger flow indices, the impact of a new line on the existing network, and the necessary concerns of essential stations. It is suggested that the forecasting work should focus on the current state of urban systems. Thus, it is essential to collect and understand the current information on urban traffic and the city itself and to analyze shortterm development trends. Because the macroscopic demand analysis models may have lower accuracy, it is also necessary to construct a thematic model for rail transit systems based on urban transport macroscopic demand analysis by conducting traffic surveys. The results of this study can provide references for technical methods and research content of passenger flow forecasting in the initial operation stage.

The subway engineering department regularly operates track inspection vehicles to detect the state of the tracks, which is crucial for residents' safe travel. The operational path of track inspection vehicles mainly relies on expert judgment, which is not only a timeconsuming practice but is also ineffective. To address the shortcomings of the current lack of systematic planning for the operational paths of track inspection vehicles, this study, set against the backdrop of the urban rail transit network, constructs a largescale subway inspection vehicle routing optimization model named Urban Track Inspection Vehicle Routing Problem (UTIVRP), under the conditions of a complex network. Considering the characteristics of subway networks, a cultural genetic algorithm with a special encoding method is designed and validated using practical examples from the Beijing subway. The computational results indicate that under the conditions of meeting the established inspection requirements, the optimization solution can not only reduce the idle mileage of vehicles by 48.88%, but also decrease the maximum deviation rate of the network's inspection interval by 93.33%.

This study comprehensively summarizes the testing scheme and results of a laddersleeper ballastless track in urban rapid rail transit for safety, stability, and vibration reduction performance compared with an ordinary ballasted track at a maximum speed of 220 km/h on the National Railway Test Center Circular Line in 2023. The test used eight CRH380AJ comprehensive inspection units, including the safety and stability of the wheelset derailment coefficient, wheel load reduction rate, wheelrail lateral force, vertical and lateral dynamic displacement indicators of the rail and sleeper, vertical and lateral vibration characteristics of the rail, and vibration reduction performance of the roadbed surface at a distance of 3.5 m from the centerline of the line. The test results for these indices were lower than the limits of the corresponding standards and close to those for the existing ballasted track. The test results show that the safety, stability, and wheelrail vibration characteristics of the laddersleeper ballastless track in urban rapid rail transit can satisfy the requirements of the line at a speed of 220 km/h. According to different weighting methods, the average vibration reduction of the laddersleeper ballastless track compared with an ordinary ballasted track in urban rapid rail transit can reach 3.35.1 dB and 4.46.8 dB. The test results provide a reference for urban rapid rail transit and intercity railway track vibration reduction technologies.

To evaluate the vibration reduction effect of urban express, similar sections with essentially the same line conditions were studied. Different vibration reduction measures and corresponding common overall track bed sections were tested onsite to study the vibration reduction effect of urban express vibration reduction measures. Through the time domain, frequency domain, and onethird octave analysis of the measured data, the vibration reduction measures and maximum Zvibration level (VLZmax) of the ordinary section of the tunnel wall were obtained, and the vibration reduction effects of different vibration reduction measures were compared. The vibration acceleration of the tunnel wall at the measuring point and the ground vibration were analyzed in onethird of an octave to obtain the propagation attenuation of the vibration. The results show that the three vibration reduction measures reduced vibration. The vibration reduction of the doublelayer nonlinear vibration reduction fastener was 7.3 dB; the vibration reduction was 16.2 dB for the vibration damping pad floating plate and 19.7 dB for the steel spring floating plate.

This study examines shield direct cutting techniques on largediameter piles within the construction project linking Guanzhou Station to University Town North Station on the Guangzhou Metro Line 12. Focusing on piles with diameters of 1,200 mm and reinforcing bars with diameters of 25 mm and 28 mm, the research evaluates the efficacy of critical measures and the resultant quality of pile cutting within shield construction. Findings indicate that a cutter head configuration, incorporating a hob and a tearing knife, successfully penetrates concrete pile foundations containing rebar of the specified diameters. However, a challenge arises when a toothed hob attempts to sever the reinforcing bar directly. It is observed that the tearing knife's secondary action exerts adequate shear force to dissect the reinforcement at the precut location by the hob. Furthermore, employing a boring strategy characterized by a low advancement rate, high rotation speed, and consistent torque has proven to enhance the cutting process for both the pile body and its embedded steel bars. Additionally, the use of split hydraulic rebar shears delivers an improved response to the complications presented by intertwined steel bars within the shield machine's path.

Groundsurface deformation characteristics caused by jacked rectangular pipes differ from those caused by jacked circular pipes or shield tunnels. The groundsettlement characteristics during the construction of a shallowburied rectangular jacked pipe and its impact on the existing shield tunnel below the jacked pipe were clarified. Using the onsite monitoring results from jacked rectangular pipe construction, the deformation patterns of the ground surface during jacked rectangular pipe construction and the deformation of the existing shield tunnel below the jacked pipe were analyzed. The traditional Peck formula was applied to circular pipejacking and circular shield tunnels; the improved Peck formula was used to describe the surface deformation caused by rectangular pipejacking. The surface deformation, pipeline deformation, and settlement pattern of the submerged tunnel caused by jacked pipes were analyzed based on field monitoring. The results show that the improved Peck formula can describe surface deformation caused by jacked rectangular pipes more accurately than the traditional Peck formula. The settlement patterns of the surface and pipeline caused by jacked pipes were consistent; however, there were differences in the settlement patterns of the underlying tunnel.

Field experiments and simulation analyses were conducted on a Kaifengsuspended monorail demonstration line to evaluate the service performance of rubbertire suspended vehicles and steel guideway bridges and provide appropriate criteria and operating and design parameters for this type of vehiclebridge system. A rubbertire suspended trainsteel and guideway bridge coupling analysis program was developed. The vehiclebridge coupling model was built according to the measured parameters, including the stiffness and damping of the pneumatic spring and travel wheels. The calculated and measured dynamic responses of the vehicle and bridge were compared. The dynamic performance of the vehiclebridge structure was evaluated based on the calculations and related specifications. The results show that 1) it is feasible to use the vehiclebridge coupling simulation method to investigate the structural vibration performance of a suspended monorail system; the simulation results were consistent with field measurement results; 2) the ratio of the vertical deflection to the span of the steel guideway girder was less than the limit given in the specifications and the vertical stiffness of the structure was reasonable; 3) the maximum vertical and lateral rotation angles between two adjacent beams at the beamends were 4.5‰ and 1.5‰, respectively; 4) the maximum dynamic factors of longitudinal and lateral stress of the steel guideway beam were 1.17 and 1.14, respectively, at a vehicle speed of 80 km/h; 5) the unloading factor of the wheel and lateral acceleration of the guideway bridge were larger than those of conventional railway systems; the limits of these two indices could be set higher than in the current railway specifications as the suspended trains were unlikely to derail.

Quality defects in segment assembly, such as misalignment and ellipse deformation, often occur during shieldtunneling excavation. Construction quality defects threaten tunnel stability and safety. To ensure the safe construction and service of shield tunnels, a quality assessment of the shield segment assembly is necessary during construction. Limited by manual detection methods, traditional sitequality assessment is challenged by low efficiency, limited accuracy, and missing data. Three dimensional laser scanning was introduced to collect pointcloud data during the assembly of the shieldsegment lining. The ellipticity and misalignment values of the shield segments were calculated by the long and shortaxis algorithms and the improved slope segmentation algorithms. Based on the theory of centerpoint extraction of ringseam data, a method for extracting the central axis and center point of a tunnel through ringsegment data fitting was proposed for high precision, efficiency, and automation to detect shieldsegment assembly quality. A shieldtunnel project was conducted to demonstrate and validate the proposed method. The results show that the proposed method can efficiently and automatically assess the assembly quality of shieldconstruction segments.