Subway Line Research Articles

The Axial City: disjunctioning radical pluralities from an urban galaxy

ABSTRACT In 1999, the City Council of Brescia (Northern Italy) approved the construction of the city’s inaugural subway line, which began operating in 2013. Since its inception, the subway has been reshaping Brescia’s urban structure. Its aim was to spatially integrate essentials urban services into a seemingly cohesive and post-industrial socio-spatial system, a process that have been termed as urban wholing. However, wholing dynamics have simultaneously solidified and splintered the city’s urban structure. Over the last decades, Brescia has evolved into an “Axial City” socio-spatially governed through the regimented mobilities emanating from the subway. This configuration is spatially marked by the presence of “hierarchized centralities” that disproportionately catalyze investments and development policies. Furthermore, the subway system establishes distinct patterns of socio-spatial (dis)junction, defining different areas as “(dis)integrated ecologies” from the city-as-a-wholed. Via this approach, the processes of wholing generate mobilities according to normative class, racial, gendered, and age-related urban relations, transforming the Axial City into a comprehensive system fueling unprecedent conditions of selective (dis)integration and “kinetic segregation.” This contribution explores the governmentality expressed by the Brescia’s infrastructure, emphasizing how the socio-spatial processes of splintering radical pluralities, intrinsic to the efforts towards wholing, are crucial conditions of injustice permeating the contemporary city’s political project.

Briefing: Vertical vibration control of over-track buildings: information for practitioners

In recent decades, transit-oriented development has emerged as a prominent trend in metropolises. Modern infrastructures and residential buildings are strategically constructed above subway lines or parking depots, facilitating convenient access to city transportation. Nevertheless, complaints regarding the vibrations induced by metro vehicles have been on the rise.

Observational Study on Passenger Behavior in the Beijing Subway

To understand the primary behaviors of contemporary passengers during subway travel, a traditional observational research method was employed to observe and record the behaviors of individuals in the last car of Beijing Subway Line 5. The observed behaviors were then analyzed and explained using relevant theories. The results indicated that: a. The main behaviors of subway passengers included activities such as using mobile phones, sleeping, daydreaming, reading, and interacting with others. b. The predominant use of mobile phones was closely related to the development of the internet era and the widespread adoption of smartphones. c. The limited communication and interaction among subway passengers were linked to the phenomenon of interpersonal apathy prevalent in modern society.

Investigation of thermodynamic parameters of the air environment in subway lines with single-track and double-track tunnels

Investigation of thermodynamic parameters of the air environment in subway lines with single-track and double-track tunnels

Energy consumption analysis of trains based on multi-mode virtual coupling operation control strategies

Urban rail transit, as a main mode of travel, has always been concerned with the balanced relationship between energy consumption and transport efficiency. The advent of the virtually coupled train set (VCTS) has significantly enhanced the efficiency of existing railway lines. Both energy consumption and comfort during the operation of VCTS control technology have emerged as significant challenges for the development of VCTS since the inception of onsite testing. A review of the current research status of VCTS control systems has revealed that the majority of current formation control systems are focused on the safe operation of formation trains, the stability of train control systems, and safe train separation models. However, a case study has shown there is a strong correlation between train operating intervals, train control strategies, and train operating energy consumption. Therefore, it is necessary to design and plan the operation modes of formation trains for different train operation requirements. This paper presents four distinct control modes, developed through the integration of the most prevalent VCTS control strategies, operational modes, and operational requirements. The design of these control modes is guided by considerations of energy consumption, safety, and comfort during train operation. A case study of Beijing Subway Line 11 revealed a significant correlation between energy consumption, control mode, and safety under different control modes. In particular, the correlation between train running intervals and energy consumption in a high-precision tracking state provides valuable technical support for the future operation of VCTS technology in different periods, scenarios, and environments.

Normativity in the embedded language policy of the Beijing subway’s spatial expression

ABSTRACT Public space plays a pivotal role in translating language policy into real-world practice. This study is grounded in empirical data collected through ethnographic fieldwork and semi-structured interviews from the Beijing Subway Line 1, which is typical of the normativity of a public space. The findings indicate that the linguistic landscape (LL) serves as a tangible representation of the inherent normativity within the subway space. Language policy implemented in the subway LL is achieved through hierarchical, process and result intervention. Hierarchical intervention addresses the synchronic stratification of normativity represented by the subway LL and its evolving connotation over time. Regarding process intervention, the subway LL utilizes two approaches to express normativity: the unity of semiotic features and indirect speech acts. Result intervention means that passengers perceive the normative representations of LL as knowledge and transform de facto language policies into experience. These intervention methods illuminate the intricate mechanism of language policy embedding in the normative representation of the LL within subway space. The harmonization of language policy with the LL, subway space, and passenger behavior collectively shapes the subway into a vital transportation hub.

Research on Multi-Objective Optimization Methods of Urban Rail Train Automatic Driving Based on NSGA-II

In order to improve the control performance of automatic train operation (ATO) in urban rail trains, five typical operating sequences of urban rail trains were studied. Under the condition of meeting the safety and comfort principles of train operation, a train dynamics model was established to achieve the goals of low energy consumption, short running time, and high stopping accuracy in urban rail transit trains. In the process of finding a multi-objective solution to this problem, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) was used with an elite retention strategy, and the optimal Pareto multi-objective solution set was sought. In the process of optimal solution weight assignment, the hierarchical analysis Mahalanobis distance method, which combines subjective and objective analysis, was used. Finally, taking the Beijing Yizhuang subway line as the background design example, the simulation verified the effectiveness and feasibility of the algorithm and obtained high-quality automatic train driving curves under various working conditions. This research has important reference significance for the actual operation of automatic driving in urban rail trains.

Method for Predicting Environmental Vibration Impact of Existing Subway Lines and Its Practical Application

To predict accurately the impact of track vibrations caused by subway trains on adjacent buildings and address the problem of their excessive dynamic response, a method for predicting the environmental vibration impact of existing subway lines is proposed in this paper. A coupled numerical dynamical model of the train/track/tunnel system is established using the multi-scale method. Using field-measured soil vibration data, empirical formulas for soil frequency and material damping coefficient are calibrated. By combining the numerical model and the empirical formulas, buildings’ indoor vibrations and noise level can be assessed. At the same time, a solution to the problem of excessive vibration of buildings along a subway line is also proposed that optimizes the track fastener parameters. Field tests verified the accuracy of the prediction method and the effectiveness of the optimized track parameters. These research results provide a reference for predicting the vibration of buildings along subway lines and using the proposed preventive solutions.

Restoration sequence optimization for vulnerable metro stations with limited budget: A case study of Beijing, China

Urban rail transit networks are essential components of urban transportation systems, but they are vulnerable to disruptions that can severely affect passenger mobility and network efficiency. Traditional methods for determining restoration sequences often rely on experiences or importance-based approaches, lacking precision in identifying critical vulnerable station combinations and struggling to find optimal restoration sequences under limited budgets. This paper introduces a three-level model framework aimed at addressing these issues. The middle and lower levels jointly identify the most vulnerable station combinations, while the upper level optimizes the restoration sequence by taking into account budget constraints and changes in resilience metric throughout the restoring period. The effectiveness of the proposed model was validated using four subway lines in Beijing, China. Results demonstrate that the model can effectively identify critical vulnerable station combinations. Additionally, the resilience-based restoration strategy effectively determines the optimal recovery plan for damaged stations under limited budgets, outperforming traditional restoration strategies based on complex networks and offering strong extensibility.

FORMATION OF A NETWORK OF EVACUATION BUS ROUTES FOR THE SALTIV RESIDENTIAL AREA OF KHARKIV

Evacuation mobility of the population during military operations or emergencies is one of the most vital tasks in ensuring the safety and rescue of citizens. Planning this mobility requires a conceptual approach, system analysis, and a comprehensive preparatory stage. The primary task for organising the population’s bus transportation during evacuation is planning routes and determining their time parameters. This process requires preliminary determination of the points of traffic organisation, establishment of routes and meeting points, allocation of resources, and coordination of work with other types of passenger transport. The study aims to develop the sequence of formation of evacuation bus routes in the Saltiv residential area of Kharkiv and to establish the functional effect of operational parameters of their work on the duration of population evacuation. The methodological basis for building a network of evacuation bus routes is a developed structural model of the impact of input parameters on the general evacuation time for the population and the transport capabilities of the routes. This model describes the functional relationship between the existing volume of passenger transportation on urban transport routes, the share of passengers subject to evacuation, the number of stopping points on evacuation routes, the length of routes, the speed of movement, the time of boarding and disembarking the passengers, the capacity of buses and their number. The criterion for evaluating the efficiency of the routes is the total time of population evacuation, depending on the number of buses on the routes. Based on the analysis of the location of shelter facilities and transfer stations on the subway line, we established that it is expedient to create seven evacuation routes that ensure the timely evacuation of the population. After assessing the available passenger traffic on city transport routes, we determined the potential demand for evacuation transportation. The analysis of the operational parameters of the routes made it possible to specify the time indicators for the evacuation of the population. The analysis of the interaction processes resulted in a diagram of the structural contour of the functional connection. The developed analytical models helped to establish several indicators characterising the operation of evacuation bus routes. The developed theoretical foundations are the basis for simulation modelling and setting the regularity of changes in evacuation efficiency assessment indicators depending on the number and capacity of buses. Based on the real-life conditions, the study determined the need to use two buses on each route to evacuate the population in the district. Such conditions will ensure the transfer of the population to the safe zones within 18.3 to 31.7 hours. Keywords: population evacuation, bus, evacuation route, volume of transportation, travel time.

Improved Subsidence Assessment for More Reliable Excavation Activity in Tehran

This paper presents a particular tunneling method, the new Austrian tunneling method (NATM), which plays an important role in reducing subsidence of the surface and damage to structures in urban areas. It has a wide range of applications in shallow tunneling projects all over the world. In this study, numerical modeling of the third-line Metro tunnel in Tehran, which is designed and stabilized by the NATM, is under discussion. The foregoing tunnel is excavated manually with a one-meter advancing step. In this project, the constructors use a lattice girder and spray concrete with 31 cm thickness as the initial lining. A suitable numerical software for this modeling is PLAXIS 3D Tunnel, which allows high-resolution finite element modeling (FEM) of the studied object. The performance of this method is investigated and compared with that of other NATMs. The numerical modeling yielded a value of 30.01 mm for earth subsidence in the most damaged area of the settlement, which was confirmed with a dramatically low difference by earth surface monitoring. Moreover, this tunnel was drilled and excavated using various methods, among which the least settlement was obtained by the proposed method. The results are promising, and they indicate that tunneling with this method should continue to be used to expand the subway line in the city.

Urban mobility and air pollution at the neighbourhood scale in the Megacity of São Paulo, Brazil

Developing countries’ megacities, characterised by dense populations and socioeconomic disparities, often face high levels of pollutants, mainly from vehicle emissions. Poor air quality can lead to a range of public health problems which in turn, need to be addressed by public policies. The main goal of this article is to examine the impact of public policies and the influence of transport modes on air pollution of three districts from the Metropolitan Region of São Paulo, in Brazil: Pinheiros, Parque Dom Pedro II and Taboão da Serra. The method was held through a comparative analysis, which in turn, took into account urban indicators, urban mobility data and pollutants levels (CO and NOx). These data were collected from the 2007 and 2017 São Paulo Metrô Origin and Destination Surveys and the Air Quality Database of the Environmental Company of the State of São Paulo. As key findings, the three study areas’ pollutant concentrations presented a downward trend from 2007 to 2017 as the same time there was an increase in the public transport and non-motorized transport modes. However, it is important to highlight the confluence of the state and federal public policies occuring at the same period such as PRONCOVE, Rodoanel and the Yellow Subway Line. The identified socio-environmental disparities in the urban realm highlight the importance of localised analyses in order to reveal problems and opportunities to get a better response in terms of urban mobility and air quality. Thus, the perpetuation of constant policy’s updates and interdisciplinary collaboration is crucial.

Diversity and Influencing Factors of Public Service Facilities in Urban (Suburban) Railway Life Circle—Evidence from Beijing Subway Line S1, China

Diversity and Influencing Factors of Public Service Facilities in Urban (Suburban) Railway Life Circle—Evidence from Beijing Subway Line S1, China

A hybrid methodology for the prediction of subway train-induced building vibrations based on the ground surface response

The numerical simulation and theoretical methods for the subway train-induced vibration of the shallow foundation buildings often suffer from high cost, unstable prediction accuracy, and lack of clarity of important parameters. Therefore, a hybrid prediction method based on the Z-vibration level at the ground surface was proposed to rapidly obtain the vibration characteristics of the shallow foundation building adjacent to the subway. The numerical simulation was first used to obtain the subway train-induced vibration of the shallow foundation building under different working conditions. Then, a hybrid model was established and retrained by combining the field measurement data of the soil and building vibration along the subway line. Finally, the prediction accuracy of the hybrid model with different numbers of measurement points as input layers was explored, and a case study was performed. The results show that the most noticeable effect on subway train-induced building vibration is the length of the building span among the shallow foundation building parameters. Three measurement points of the Z-vibration level at the ground surface are suggested as the training set data for the input layer of the hybrid model in consideration of computational efficiency and accuracy. The prediction accuracy of the hybrid model gradually increases as the number of data sets increases, and the fully trained hybrid model performs more stable across the frequency range compared to the traditional model, with the majority of its predictions in the 90% confidence interval, which provides the possibility of simplifying the analysis and fast prediction of subway train-induced building vibration.

Simulation Study on Ground Vibration Reduction Measures of the Elevated Subway Line

Simulation Study on Ground Vibration Reduction Measures of the Elevated Subway Line

Field experiment and simulation of hot air curtain for cold protection in subway aisle in severe cold regions

Harbin Subway is the northernmost subway line in China. In winter, outdoor temperature can reach −37.7 °C. Cold protection has emerged as a critical priority for subway operations in the region. In this paper, taking the aisle of a typical island station in Harbin as the research object, long-term and short-term field experiment on the thermal environment of the aisle were carried out. The field test data of the station and the full-scale model were used to conduct numerical simulations on the effect of supply air temperature, speed, and angle on the aisle environment. The modified PET temperature scale and average power consumption during the operation of the hot air curtain were used to evaluated the cold protection solutions of the air curtain. The results revealed that the average temperature of the cross-sections in the aisle without cold protection measures dropped by 5.4 °C–6.3 °C from its initial level after the train left the station. Without increasing average power consumption, changing the supply air angle of hot air curtain can improve the thermal environment in the aisle. Considering the three aspects of cold protection effect, passenger thermal comfort and power consumption, this paper recommends that the cold protection solution for aisles with a length less than or equal to 76.7 m, L-shaped and similar layouts is 35 °C for the supply air temperature, 9 m/s for the wind speed, and the range of the difference between the supply air angle and the aisle inclination angle is 6° <θ-α < 11°.

Understanding land subsidence in the Pearl River Delta region of China based on InSAR observations

Land subsidence occurs in river delta areas. A comprehensive understanding of the factors contributing to land subsidence is crucial for effective geohazard mitigation and land planning. This study investigates the distribution characteristics and spatiotemporal evolution pattern of the land subsidence in the Pearl River Delta based on the InSAR-derived ground deformation data spanning 2016 to 2021; and, the effects of the influencing factors, including the Quaternary sediment thickness, land use classification, land reclamation, and subway construction and operation, on the subsidence are analyzed. The results unveil the presence of four major subsidence zones and several minor coastal subsidence bowls in the research area, with a total area of about 1100 km, all of which exhibit prolonged and intense subsidence. In the remaining regions, land subsidence predominantly exhibits weak and short-term occurrences. The subsidence in the study area follows a distinct linear evolutionary pattern with a slight rebound, potentially linked to the rise of groundwater levels. Regions with Quaternary sediment thickness surpassing 20 m, engaging in aquaculture or agricultural activities, and featuring reclaimed land are predisposed to prolonged and intense ground subsidence. In addition, the construction and operation of subway lines may induce ground subsidence, especially in geologically vulnerable areas. This study provides valuable insights into land subsidence research in delta regions.

Joint risk-based maintenance strategy and integrated monitoring approach for manufacturing system operational process considering workpiece quality

The fluctuation of various parameters in the production process increases the risk of generating unqualified products and suffering from systematic failures and downtimes, and the preventive maintenance and control of potentially faulty machines in manufacturing systems should consider the continuous increase of operational risk. Therefore, to proactive control the manufacturing system operational risk, a joint model of risk-based maintenance (RBM) and integrated monitoring is proposed. The proposed model formulates an appropriate maintenance strategy and appropriate control charts for monitoring the manufacturing process, guaranteeing the stable operation of the manufacturing system. First, considering the co-effect of the production equipment state and workpiece quality, a novel connotation of the manufacturing system mechanism’s operational risk is proposed, and the RBM framework is constructed. Second, considering the manufacturing system operational state, an integrated maintenance decision-making model based on different risk scenarios is established using a dynamic monitoring scheme based on EWMA control charts. Third, a particle swarm optimisation algorithm is adopted to optimise the proposed model to obtain the optimal maintenance strategy for production equipment and monitoring parameter for workpiece quality. Finally, the effectiveness of the proposed approach is illustrated with a case study on a subway current receiver production line.

Robustness Assessment of the Metro System: A Case Study of Bucharest, Romania

Metro network systems play an important role in urban transportation but they are vulnerable to various risks and disruptions. Having a comprehensive understanding of these risks is essential for their operation. In this paper, we aimed to assess the operational robustness of the Bucharest metro system. We employed graph theory and concepts. Using available data specific to the Bucharest metro system operation, we analyzed the type of disruptions across metro lines and stations. As expected, the two subway lines that sub-cross the city center experienced the greatest number of disruptions. Several stations on Line M1, that sub-cross the central urban area, were found to be particularly vulnerable. In our analysis, the results are as follows: the robustness indicator for the metro network, rT, is 0.1538, and the effective graph conductance (CG) is 0.1. These reveal that the Bucharest metro network can withstand up to 45% of node failures before collapsing. This indicates moderate robustness, suggesting that while the network can handle specific disruptions, targeted improvements are necessary to enhance overall resilience.

Rail Structural Health Monitoring using ultrasonic guided waves: system design and deployment

Railways are a central industrial infrastructure enabling people and goods transportation all across the globe and their use is due to increase in the forthcoming years to reduce the overall carbon footprint of our modern societies. Hence the need to ensure their reliable use, as traffic interruptions or accidents can have dire social, economic and environmental impacts. In particular, rail breaks can produce such incidents and need to be monitored and prevented if possible. Ultrasonic guided waves are a promising physical phenomenon to monitor rails as they can enable the monitoring of long portions with a limited number of sensors. This talk will present a SHM system relying on such waves for rail monitoring which has been deployed for industrial tests on a subway line. The electronics, the sensors and their coupling to the rail were optimized to ensure the measurement of guided waves after a long-range propagation throughout the life of the system. Indeed, specific couplings are needed to enable long-time coupling, and so ultrasound sensitivity of the system, while the rails are bearing high loads or dilating due to temperature changes. An experimental campaign was carried out to evaluate the sensitivity of the system to rail breaks, and to demonstrate its detection under representative, uncontrolled environmental conditions. Particular considerations linked to pulse-echo inspections, inducing a sensitivity to cut-off frequencies and zero-group velocity modes, will be presented.