To promote the quality and efficiency of inventory areas in metropolitans, urban renewal of transit station areas in cityn centers presents an urgent challenge. By incorporating the Quality dimension into the traditional NodePlace model to indicate the perception of spatial environment, this study constructs the NodePlaceQuality Rubik's Cube state model to assess the renewal potentialof transit station areas in the downtown. Using Tianjin's central area as a case study, the modeling results show that the proportion of dependent and imbalanced types of transit station area is as high as 35.49% and 38.71%, respectively, while balanced and coordinated types account for 22.58% and 3.22%, respectively. The transit station areas with high renewal potential are concentrated in the edge of the Inner Ring of Tianjin, and the renewal potential of transit station under construction is also relatively high, while the transit station areas with low renewal potential are agglomerated in the central business district (CBD). These findings provide theoretical support and policy insights for the urban renewal in the transit station area in the metropolitan's downtown.

By the end of 2024, a total of 28 provinces and 58 cities in Chinese mainland have opened 362 urban rail transit lines, covering a total length of 12,168.77 km, including 9,281.37 km of subway lines, accounting for 76.27%. By the end of the statistical period, 1,486.01 km of Fully Automated Operation (FAO) lines have been opened, representing 12.21% of the total length of operational lines. In 2024, 51 new urban rail transit lines (sections) were added, with a total length of 953.04 km, including 738.26 km of new metro lines and 425.70 km of new FAO lines, all of which were classified as GoA4. It is expected that by the end of the 14th FiveYear Plan period, the total operating scale of urban rail transit in mainland China will exceed 13,200 km. It is estimated that the annual passenger volume at the end of the 14th FiveYear Plan period will double compared to the end of the 13th FiveYear Plan period.

This study uses multisource big data (e.g., metro card transactions, mobile phone signaling, and points of interest (POIs)) and interpretable machine learning methods (integrating random forest and Shapley additive explanations (SHAP) models) to investigate the nonlinear relationship between stationarea built environments and Chengdu Metro ridership as well as the synergistic effects among built environment variables. The results indicate that the three most important built environment determinants of metro ridership are the floor area ratio, employment density, and road density. Moreover, the SHAP model results reveal the threshold and synergistic effects of the stationarea built environment variables on metro ridership. These findings provide theoretical support and policy insights for transitoriented developmental (TOD) planning and practice.

Renovating existing lines is a key longterm task for achieving highquality and sustainable development of urban rail transit in China. Technical standards are essential for initiating, designing, and implementing renovation projects. This paper reviews the current technical standard system for urban rail transit and examines the suitability of existing standards for each stage of the renovation process. To address the issues of incomplete coverage, low applicability, and poor relevance of existing standards, we propose two approaches and schemes for developing a new technical standard system for renovating urban rail transit lines, along with the principles for constructing and formulating the standards. We focus on the technical standards for renovation, including the requirements for renovation determination, design, construction, acceptance, safety assessment, and postevaluation.

This paper addresses the problem of mismatch with the surrounding urban renewal when applying the TOD stationcity integrated development model to domestic rail transit stations. Based on the classic nodeplace (NP) model and the introduced nodeplaceridership (NPR) model with passenger flow, this study takes Xi'an Metro Line 3 as an example. Relying on spatiotemporal big data, passenger flow data within 24 hours for six consecutive months are selected to calculate the basic indicators of 26 stations, which are classified into six categories: placeahead and low ridership, deficient and low ridership, matching and midlow ridership, nodeahead and midhigh ridership, nodeahead and midlow ridership, and saturated nodeahead and high ridership. This results indicate that Xi'an Metro Line 3 has the characteristics of a relatively higher node value and a lower place value. Given the identification of the same characteristics across the six station types, we propose precise matching strategies for placeahead, coordinated, and ahead type stations. Specifically, placeahead stations should prioritize connection with other transportation modes and pedestrian accessibility, coordinated stations should optimize supporting facilities and explore the potential of place features on this basis, and ahead stations should integrate resources to form railway microcenters. These three processoriented transformation measures can be applied to other regions and contribute to improved station function and service.

The positive externalities of urban rail transit necessitate a comprehensive economic costbenefit analysis when evaluating project economic feasibility. In response to the latest requirements for preparing the outline and explanation of the project feasibility report, this study conducted a multidimensional study on the economic costbenefit of urban rail transit. Firstly, identify economic costs and benefits from three dimensions: government, enterprises, and the public, establish a threelevel quantitative+qualitative indicator system, expand quantitative indicators from 5 to 13, and add 14 qualitative indicators; Secondly, conduct research on key indicator analysis methods, propose quantitative methods for driving GDP, fiscal revenue, and increasing employment, break through the current difficulties in evaluating the macroeconomic contribution of urban rail transit, and improve the calculation methods for time saving benefits, fatigue reduction benefits, and traffic accident reduction benefits; Finally, it is clarified that there are 9 indicators that can be included and 4 indicators that cannot be included in the economic costbenefit analysis flow table, and a comprehensive evaluation of the project's economic costbenefit is conducted through case studies to provide support for earlystage decisionmaking and promote sustainable development of the industry.

Synthetic sleepers of fiberreinforced polyurethane foam were initially applied in urban railway traffic to adapt to the linear induction motor system, and they have been developed into national and heavyhaul railways in recent years. Synthetic sleepers have been widely researched and applied nationwide owing to their excellent overall performance. The technological development history and standards of synthetic sleepers in China were analyzed and compared with foreign and ISO standards. In addition, the application progress, application problems, and solutions were investigated. Suggestions for the development and prospects of polyurethane synthetic sleepers in China were proposed by combining the requirements of domestic rail traffic with the application problems of synthetic sleepers.

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.

The Beijing Northeastern Ring suburban railway renovation project aims to transform the line into a public transitstyle operation, with portions of the route cooperating on shared tracks with Subway Line 19. While enhancing passenger service, the line must preserve its critical function as a connector within the main railway network. The system design requires a maximum throughput of 20 train pairs per hour. The existing Changping Station, which serves as both a turnback station for the Northeastern Ring Line and a connection point to the vehicle depot, is characterized by its large scale and operational complexity, making it the bottleneck for system capacity. This station becomes the critical factor in determining whether the system's maximum capacity requirements can be achieved. The Northeastern Ring Line adopts the CTCS2 train control system with ATO and automatic turnaround capabilities. To enhance Changping Station's capacity and meet system requirements, modifications were implemented to the existing station layout and signaling system. The station tracks, throat areas at both ends, and connections to the main line were optimized. Combined with signaling improvements and verified through traction calculations and multiscenario timetabling, Changping Station ultimately achieved a throughput capacity of 23 train pairs per hour, not only satisfying system requirements but also providing a 15% capacity margin. Through comprehensive analysis of Changping Station's capacity, the study identified that the number of arrival and departure tracks, length of station throat areas, signal configuration, and operating speeds are the primary factors limiting station capacity. The paper proposes solutions for improving station throughput capacity, providing valuable reference for future suburban railway design projects.

Mediumand lowvolume rail transit, as a supplement to metro networks in super or mega megacities and as the backbone of large and mediumsized cities, is essential for solving urban traffic problems. Based on a survey of more than 2600 mediumand lowvolume rail transit operation lines in 496 cities in 65 countries, a database of mediumand lowvolume rail transit lines worldwide was constructed. Based on this database, 9 types of mediumand lowvolume rail transit systems (gear rail, tram, suspended monorail, automated people mover systems (APM), straddle monorails, linear motor systems, mediumand lowspeed maglev, electronic guidance rubbertired system, and beamguiding rubbertired system) have been obtained worldwide, with a total length of 18 744.84 km. And statistics were conducted on the distribution of mediumand lowvolume rail transit in various continents and countries. The results showed that it is mainly distributed in 32 countries in Europe, including Germany and Russia, with a total length of 13 256.0 km, accounting for 70.7%. Statistics show that the distribution of various rail transit systems in different countries/cities, with different urban characteristics and functional positioning of different lines shows that mediumand lowvolume rail transit systems mainly serve cities with a population of less than 3 million. 76.25% of tram lines, 47.82% of straddle monorail lines, and 42.11% of linear motor system lines are backbone lines, 84.62% of gear rail lines are tourist lines, and 70.73% of APM lines are airport dedicated lines. Additionally, the origin and development of each system are summarized, and the technical characteristics, parameters, and applicability of each system are analyzed. The results provide a reference for the selection of urban medium and lowvolume rail transit systems in China.