A vehicle speed measurement platform was developed to address the problem of diverse speed sensor models and an excessive number of sensors. This study outlines the overall design principles of the speed measurement platform, informed by an analysis of speed requirements for systems including vehicle traction, braking, signaling, and running gears. The proposed technical scheme advocates for the unification of speed sensors across various vehicle systems and introduces a method for calculating vehicle speed by integrating data from speed sensors and accelerometers. Additionally, it provides a technique for calculating the reference wheel diameter in conjunction with ground responder equipment information. The platform features two flexible methods for transmitting speed information: hardlines and networks. The research findings indicate that, compared to traditional speed measurement methods, this platform offers a unified and more accurate source of vehicle speed information, effectively meeting the requirements of traction, braking, signaling, and running gear systems.

To address issues related to the size effect of deep circular shaft excavation for rail transit, this study analyzes the stress and deformation characteristics of a circular excavation enclosure structure using the foundation pit project of the ShenzhenDaya Bay Intercity circular working shaft as a case study. The loadstructure method is employed to systematically examine these characteristics under various diameter conditions. The study compares the calculation results from both a 3D spatial structure model and a 2D elastic foundation beam model, discussing the impact of excavation size on the performance of the circular enclosure structure. The findings reveal that the circular diaphragm wall behaves as a quasicircular structure, generating a vertical bending moment due to soil and water pressure, which indicates a multidirectional stress state. It is feasible to utilize a simplified 2D equivalent model for designing a circularfoundation pitretaining structure, as its calculation results are more conservative than those of the 3D model. Furthermore, the spatial dimension significantly influences the performance of the circular enclosure structure, with noticeable circumferential effects observed when the diameter of the deep circular working shaft is less than 30 m.

In response to the increasing speed and strict requirements for bridge smoothness in the design of railelevated bridges, this study is based on the design of the elevated bridge of Beijing Metro Line 22 at a speed of 160 km/h. A new type of adjustable height device is developed and designed based on a lowmeltingpoint alloy as the height adjustment medium. A series of experimental studies are conducted, including the structural design of the device, indoor temperature and pressure tests, fullscale pressure adjustment performance tests of the compression shear machine, and onsite beam erection tests. The findings indicate that the new adjustable height device enables stepless bidirectional height adjustment with a rapid adjustment speed, completing height changes within 30 s. The device achieves millimeterlevel accuracy, and the alloy demonstrates excellent stepless adjustment performance and compression stability once cooled and solidified. The accuracy and stability of this adjustable height device not only ensure the smoothness of elevated bridge beams but also offer valuable guidance for engineering applications, such as replacing deteriorated bearings and adjusting for differential settlement in bridges.

Considering the contradiction between construction intentions and financing conditions in China, this study employs a case study method to examine the investment and financing model of the London suburban railway. First, this paper outlines the general overview, operational process, and social and economic benefits of the Crossrail suburban railway line. Next, it analyzes and discusses the proportions and amounts of investment from central and local governments, as well as the contributions from various beneficiary entities within the “coinvestment by central and local governments+contributions by beneficiary entities” model. Finally, the investment and financing experience of Crossrail is summarized from the perspectives of central and local coownership, attracting social beneficiaries, TransitOriented Development (TOD)Integrated Development, and attracting other transportation enterprises. The results of this study can provide reference for the investment and financing of suburban railway and the entire urban rail transit industry in China.

Rail vehicles may experience abnormal vibrations, noise, and structural fatigue failure because of the unreasonable modal mismatch between an entire vehicle, equipment, and bogie. To investigate the modal parameters of bogies, experimental and simulation analyses were conducted. Initially, a modal identification method was employed, utilizing the running state environment as excitation. The crosscorrelation function of the structure's vibration response signal output was used to replace the frequency response function, in conjunction with the PolyMax modal identification method, to effectively identify modes that are easily excited during the structure's operation. Next, the effects of wheel turning and variations in vehicle load on the operating modes of the structure were examined to gain a comprehensive understanding of the bogie structure's modal parameters. Finally, a finite element simulation method was used to calculate the modal frequencies of the bogie structure in the free and constrained states. The results showed that wheel turning had little effect on the modal parameters of the structure. However, with increasing load, the modal frequencies at all orders generally increased. This was related to the increase in the air spring stiffness of the bogie owing to the increased vehicle load, even if the boundary constraint state of the structure changed. By comparing the test results with the simulation analysis results of the bogie structure in the free and constrained states, it was concluded that it is necessary to simulate the actual boundary constraint conditions as much as possible to ensure the accuracy of the finite element model. These findings can provide a reference for subsequent studies on modal mistuning designs.

To explore the impact of travelers' subjective spatial perceptions on travel behavior in the context of distinct urban terrain, this study takes Lanzhou, a typical rivervalleytype city, as an example. It establishes an integrated model of SEMLogit and explores the impact of the spatial perception of rivervalleytype city travelers on rail transit travel mode choice based on questionnaire data. The results show the following: ① Compared with the logit model without considering travel space perception, the goodness of fit of the logit model considering travel space perception by SEM increased by 0.234, and the prediction accuracy increased by 7.75%. ② The spatial perception of travelers in rivervalleytype cities has a significant positive impact on the choice of rail transit travel intention and behavior. ③ The spatial perception of travelers in the rivervalleytype city from five aspects, including the unnecessary detour, rivers in the river-valley-type city, wasp waist blockage, convenience of inter-group travel, and degree of being affected by road slope, l significantly influences travelers in the river-valley-type city to choose rail transit. The degree of influence decreases sequentially among these factors.

In response to the problem of a relatively single smoke exhaust mode and low smoke exhaust efficiency in the public area of a subway station, this study considered the public area of a certain urban rail transit station concourse as an example to establish eight different smoke exhaust conditions, focusing on the smoke exhaust efficiency of opening smoke exhaust outlets at different positions. Through simulations, the relationships between visibility, temperature, and carbon monoxide (CO) concentration over time under different working conditions were obtained. The research results show that when a fire occurs in the public area of a subway station concourse, it is not better to open more smoke exhaust outlets but to determine according to the opening position of the smoke exhaust outlets. Opening the smoke exhaust outlet during the horizontal spread stage of smoke will interfere with the horizontal layered flow of smoke and intensify the heat and material exchange between the upper layer of smoke and the lower layer of cold air, resulting in a decrease in the height layer with a temperature of 60°C and a visibility of 10 m, which is not conducive to personnel evacuation; When the fire source is located at the most unfavorable point of the smoke exhaust system in the middle of the public area on the concourse level, the smoke exhaust outlet near the smoke barrier wall in the middle of the public area on the concourse level should be opened normally to smoothly discharge the accumulated fire smoke.

This paper proposes a combined support system comprising retaining piles, tensioned anchor rods, and inclined anchor cables with grouting to solve the problems associated with constructing supporting structures for deep excavations near obstacles on one side. The study utilized Midas software for modeling, and singlefactor optimization analysis schemes were designed considering four aspects: spacing and diameter of tensioned anchor rods and number and length of segments for inclined tensioned anchor cables. The rationality of this scheme was validated using engineering examples. The results showed a match between the simulated trends of the horizontal and vertical displacements of the slopeprotection pile tops and the monitoring results. The vertical displacement exhibited a parabolic trend, and the horizontal displacement exhibited an arched shape. The maximum horizontal displacement of the pile tops decreased as the spacing of the tensioned anchor rods decreased and increased as their diameters and the number and length of segments of inclined tensioned anchor cables decreased. During construction, the deformation of subway ancillary structures was wellcontrolled and significantly less than that of the adjacent deep excavation. The top settlement showed a fluctuating upward trend, whereas the deep horizontal displacement had a middlehigh and endlow pattern at different excavation stages. As the excavation depth increased, the subway structures' maximum horizontal deformation shifted downward along the shaft wall.

This study examines the impact of shield tunneling excavation speed and slurry solidification time on the buoyancy of tunnel segments, focusing on the section between Tongyuan Road Station and Xinggang Street Station on Suzhou Metro Line 5. A threedimensional finite element model of shield tunnel segments was developed using Winkler elastic foundation beams, considering the dynamic and static buoyancy effects generated by synchronous and secondary grouting on the pipe segments. The analysis assessed how excavation speed and grouting solidification time influence the uplift and misalignment of the segments. Results showed that both uplift and misalignment increased with higher tunneling speeds. The upward floating problem mainly occurs at the bottom of the pipe segment in the nonsolidified section of the slurry, whereas the misalignment mainly occurs at the junction between the nonsolidified section and the shield tail section, as well as between the nonsolidified section and the solidified section of the slurry. To avoid floating and misalignment of the pipe segments from exceeding the specification requirements, the excavation speed of the shield machine should not exceed 10 rings per day. Furthermore, it was observed that as the solidification time of the slurry increased, the amount of floating and misalignment of the tunnel segments gradually increased. Therefore, the use of a fastsetting and early strength dual liquid slurry is beneficial for controlling the floating of shield tunnels.

To predict the vibration response of buildings along subway lines quickly and reasonably, a building structural system is decomposed into two parts, namely, a propagation structure and a response structure, based on the theory of mechanical mobility. The bearing structure is assumed to be a beam element model, and the slab structure is considered a plate element model. The mobility formula and the corresponding matrix expressions for each unit system are derived, and a traininduced structural vibration response model is constructed. The reliability and accuracy of the model are validated through onsite testing, showing that the predicted structural responses align well with measured vibrations in both time and frequency domains. In the frequency domain, the maximum error of the center frequencies of each 1/3 octave band does not exceed 5 dB, indicating that the proposed traininduced structural vibration response model can quickly and effectively predict the structural vibration response and that the outcomes can provide theoretical support for vibration prediction along subway lines.