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.

The concept of speed efficiency was proposed to measure the travel speed efficiency of urban rail transit lines. This study analyzed the operating data of 170 urban rail transit lines in China, including fully closedoperated subway, light rail, and monorail systems, considering only the train operating mode at station stops. The analysis covered various factors such as average station spacing, line design speed, and travel speed. The results showed that most lines (approximately 64%) have a design speed of 80 km/h, with average station spacing ranging from 1.0 to 2.5 km. Among these lines, about 90% have a travel speed between 30 and 40 km/h, with speed efficiency distributed between 37.5% and 50.0%. Additionally, the study quantitatively analyzed the relationships between travel speed, average station spacing, and design speed, finding both positive and negative correlations. Finally, based on fitted travel speed and speed efficiency formulas and actual data, the corresponding distribution relationships of average station spacing, design speed, travel speed, and speed efficiency were calculated. These findings provide a reference for determining a reasonable travel speed range and speed efficiency for urban rail transit lines.

With reference to internationally recognized statistical, urban rail transit is categorized into three major types, namely metro, light rail and tram. This analysis reviews the current status of urban rail transit operations worldwide. The findings show that by the end of 2024, 562 cities in 79 countries and regions around the world have opened urban rail transit systems, with a total length of more than 44,730.14 km. Subways, light rails, and streetcars each account for 51.24%, 10.43% and 38.34%, respectively. As of December 31, 2024, 65 cities in China (including Hong Kong, Macao and Taiwan) have operational rail transit systems, with an operating length of 12,844.57 km, of which the operating length in Chinese mainland is 12,168.77 km. In 2023, the metros of 188 cities in 59 countries around the world transported a total of 713.78 million passengers, with an average daily load of 0.85 million trips per kilometer. In China (including Hong Kong, Macao, and Taiwan), metro systems carried 31.81 billion trips annually. China's urban rail transit continues to grow steadily, with the size of its network and passenger volume ranking first globally. Additionally, 233 cities in 54 countries and regions have opened suburban railways, totaling 64,195.23 km, with 21 cities in China (including Hong Kong, Macao, and Taiwan) operating 2,974.40 km of suburban railways. An analysis of the scale and development of rail networks in key countries suggests that the construction of suburban railways in China, as well as the interconnection of different networks, holds significant potential.

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.

In order to analyze the development and current research status of urban rail transit network performance evaluation, in urban rail transit networks this paper conducts a quantitative analysis of the literature from the CNKI database based on CiteSpace software. This paper gradually focuses on three levels of research: urban rail transit, urban rail transit network, and urban rail transit network performance evaluation, and analyzes the information such as the number of publications, authors, literature sources and keywords. By tracing the important literature, the main indicators of rail transit network performance evaluation are summarized, and the advantages and disadvantages of different evaluation methods are commented. The results show that the research on performance evaluation of urban rail transit networks is undergoing several important transformations. Firstly, the analytical model is developed from unweighted network to weighted network model, which pays more attention to the differences between stations and intervals. Secondly, the research object was extended from the analysis of rail transit network to the comprehensive evaluation of coupled transportation networks such as railroad and railbus. Finally, the research focus of network performance has gradually shifted from the resistance ability under disasters or external shocks to the resilience evaluation including the postdisaster recovery ability.

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.

This paper provides a comprehensive overview of Chinese mainland's urban rail transit development in 2023. By the end of the year, 28 provinces and 59 cities had 338 urban rail transit lines in operation, spanning 11,232.65 km. Subway lines made up 76.10% of this length, with 8,547.67 km, followed by fully automatic operation (FAO) lines with 9.37% and 1,052.43 km. The network expanded by 884.55 km in 2023, with 53 new lines (or sections) opening, including 539.50 km of subway lines and 252.79 km of FAO lines. The new lines involved 7 different system types and 30 cities, 3 of which inaugurated their first urban rail transit systems. In 2023, Chinese mainland's urban rail transit network also set a new record of annual passenger volume, surpassing 80 million passenger trips per day on average.

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.

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 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.