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.

Fire is one of the most serious accidents occurring at urban rail transit stations. A scientific and reasonable safety evacuation plan is essential to ensure the safety of passengers in the event of a fire. However, it is difficult to dynamically adjust the evacuation routes in the current subway station fire evacuation plan according to the fire situation. This study used computer vision technology to identify personnel distribution information and fire locations based on the monitoring system in the subway station. A spatial topology model was developed, and an improved ant colony algorithm was used to plan an evacuation route that takes the shortest time and has fewer turns to provide a more scientific and reasonable evacuation route for evacuating passengers. The effectiveness of the evacuation plan was verified by applying it to three scenarios.

As subway construction in China continues, the network operation mode of subway emerges, and more transfer nodes are created. Due to planning and other factors, the earlierbuilt subway lines did not reserve future transfer access conditions. Thus, when new lines are built, the existing stations often undergo transfer transformation and upgrading along with the new stations. Among the key tasks involved, the communication transmission system transformation and upgrading is crucial. The communication system is the traffic nerve of urban rail, which consists of public security communication system, civil communication system, and special communication system. It supports the information exchange between the control center and the stations and vehicles, and provides stable communication service for passengers. This paper examines the communication room transformation and communication capacity expansion requirements resulting from the transfer station transformation under the existing line operation conditions, and proposes the enhanced MSTP construction scheme for public security transmission system and the backbone transmission system OTN construction scheme. Xitucheng Station of Beijing Metro Line 10 intersects with the newly built metro Changnan Line, and the transfer station changes in building structure and function have raised new requirements for the communication system equipment deployment and upgrade. This paper applies the design scheme to the transfer project, verifies the rationality of the proposed scheme, and the research results offer an application reference scheme for the communication system upgrade of the existing station transfer transformation.

With rapid urbanization, the refurbishment of urban railway lines is crucial for advancing highquality urban rail development and sustainable urban growth. This refurbishment process presents a host of intricate professional challenges that must be addressed. Meeting current requirements for line reconstruction while addressing safety issues and expanding beyond traditional specialized fields is demanding. Therefore, it is essential to chart a development path for the transformation of existing urban rail transit lines in line with the needs of highquality urban rail development. Drawing on the history of Beijing's line refurbishments, this study examines the challenges and future objectives of urban rail transit line refurbishment and proposes comprehensive concepts for the rejuvenation process. Furthermore, we introduce an innovative approach to investment and financing for line refurbishments, focusing on sustainable urban rail development. We offer recommendations for the transformation of urban rail transit lines in China across six key areas: system development, vitality of components, investment and financing frameworks, technological empowerment, research and development, and relevant standards.

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.

With the early opening of urban rail transit, Shanghai has been a forerunner in urban rail transit operatingline renovation in China. The experiences and lessons learned from Shanghai in operatingline renovations have reference value for other cities in China. First, the operatingline renovation process of the Shanghai urban rail transit was reviewed. Three main development trends indicate that the focus is on a gradual transition from individual conditions to overall conditions, that the renovation contents are gradually being diversified and systematized, and that the renovation demands that align with the development goals of the city and urban rail transit network are continuously deepening and expanding. Second, developing a renovation plan with systematic thinking, minimizing the impact on passengers while ensuring construction safety and quality during renovation, and active postevaluation after renovation are summarized as the key points in the operatingline renovation of Shanghai urban rail transit. The difficulties in operatingline renovation of Shanghai urban rail transit were analyzed in terms of limited financial support, highefficiency requirements for internal and external communication, challenges in project management, and insufficient technology. Important future works for operatingline renovations of Shanghai urban rail transit are discussed, including additional financing channels, research on improvement and innovation of construction plans and management mechanisms, deeper evaluation of the operational urban rail transit network, and the technology of nonclosure renovation of underground stations without prereserved conditions.

Under the major strategic deployment of a dualcarbon strategy, studying the whole lifecycle carbon emissions of rail transit and reasonably quantifying its carbon emission level is essential to achieve peak carbon and carbon neutrality in the transportation sector. Based on a new metro line in Beijing, this study analyzes the whole lifecycle carbon emissions of rail transit, establishes a carbon emission calculation model for the whole line and the whole lifecycle of rail transit, and quantitatively calculates the carbon emission of the whole line and the whole lifecycle of the new metro line. Carbon reduction measures in the construction and operation phases are analyzed simultaneously, and their carbon reduction potential is quantitatively assessed. The carbon emission calculation for the 81km long new metro line yields a carbon emission of 2.57 million tons of CO2eq in the construction phase, 54,000 tons of CO2eq per year in the operation phase, and a total carbon emission of 5.24 million tons of CO2eq in the 50year operation cycle. The use of renewable materials and prefabricated structures in the construction phase can reduce carbon emissions by 7%. The use of comprehensive carbonreducing measures in the operation phase can reduce carbon emissions by 27%, and the carbon reduction potential of the 50year operation cycle is 17%. The establishment of the model has guiding significance for the quantitative calculation of carbon emissions in the whole life cycle of urban rail transport, and the research results of the carbon reduction measures can provide a reference for urban rail transport to achieve a green and lowcarbon transformation and carbon peak and carbon neutrality in the transport sector.

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.

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).

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.