Underground Public Transportation Research Articles

Effects of large skylights on lighting and thermal environments in underground public transport hubs: A case study in Shenzhen

Large skylights in underground public transport hubs are designed to introduce natural light and reduce the energy consumed by artificial lighting. Although large skylights can improve the lighting environment of underground public transport hubs, they also increase energy consumption due to solar radiation. Therefore, there is an urgent need to balance the improved lighting and energy consumption associated with large skylights and to determine the optimal design scheme. There are few studies on the lighting and thermal environments of underground public transport hubs, and the optimal design scheme for large skylights is unclear. Therefore, in the current study, field tests were conducted to analyze the lighting and thermal environments of two underground public transport hubs located in Shenzhen: Shenzhen North Station and Futian Station. In addition, multiobjective optimization was carried out for the large skylight at Futian Station. The results showed that most passengers were satisfied with the lighting and thermal environment under large skylights, but they were less satisfied in the summer than in the winter. Therefore, appropriate shading measures should be considered to reduce the effect of large skylights on passengers’ thermal comfort in the summer. Furthermore, the results of multiobjective optimization indicated that the large skylight at Futian Station led to a 28.1 % reduction in annual air conditioning-induced energy consumption, a 31.5 % increase in the lighting performance index (UDI), and a 43.8 % increase in the human thermal comfort index (CTR). The results of this study could provide guidance for the design of large skylights in underground public transport hubs.

Towards inclusive underground public transportation: Gender differences on thermal comfort

As urbanization and societal needs grow, the demand for inclusive, efficient, and sustainable underground public transportation has increased, necessitating a greater focus on enhancing passengers' thermal comfort. However, limited research has addressed the subway station environment, and restricted datasets are challenging to build an accurate nonlinear model. Therefore, this study proposes a thermal comfort data generation algorithm based on 5161 measured data via the Variational Autoencoder (VAE) framework to break data collection constraints and increase thermal comfort model accuracy. By employing a gradient boosting algorithm on the extensively generated dataset, this study investigated factors influencing thermal comfort in subway stations, emphasizing individual gender differences and dynamic environmental variables. The VAE model enhanced the thermal comfort dataset, resulting in a 29% and 35% increase in male and female test set accuracy, respectively. The study suggests that males with a BMI over 27 were more sensitive to temperature. As for the gender-friendly environmental features, people feel most comfortable at temperatures between 24 and 29 °C and relative humidity levels between 20% and 70%. Additionally, the study reveals that a stable environment promotes enhanced thermal comfort for passengers. These insights contribute to developing sustainable, equitable, and user-friendly underground public transportation systems.

Integrated workflow with mobile mapping survey and BIM approach to digitalize subway infrastructures

The planning and management of underground public transport is a central challenge for industrialized countries. Since an increasing number of human activities is polarized in metropolitan areas, the effort put into the digitalization for management of the underground lifelines is growing. This paper presents an innovative methodology (SCANtoBIM) to carry out digitization, inspection, and diagnostics of existing underground tunnels to obtain a digital model without disruptions. The multi-dimensional survey system (ARCHITA) allows for collecting data about the tunnel geometry, structural, and functional conditions. Data digitalization and analysis give as-built CAD models and Building Information Models (BIMs). Within the framework of the Management and Identification of the Risk for Existing Tunnels, the proposed process helps the infrastructure manager during the facility service life. The workflow for the digitalization and diagnosis from mobile mapping data has been implemented to obtain a BIM model representing more than 40 km-long metro tunnels.

3D urban transport environment

The paper investigates issues related to the solution of problems in the development of public transport infrastructure in urban agglomerations. The opportunities of further development of the existing typical city public transport infrastructure have been studied. The conclusion about the possibility of reforming the existing typical urban public transport infrastructure is drawn. It is proposed to use the available airspace together with the ground and underground public transport as a direction for the development of urban public transport infrastructure. The formation of an urban transport 3D environment is studied. It is shown that the joint application of all three urban transport environments will significantly expand the potential of urban public transport infrastructure. The possibility of using ultralight aircraft as an air vehicle is considered. It is proposed to use new types of aircraft as air vehicles. The prototype of an aircraft based on cylindrical vane propellers under the code name “Cyclolet” is described. Its flight technical characteristics are given. The conclusion about the possibility of using an aircraft of the “Cyclolet” type on the basis of cylindrical vane propellers as an air vehicle in the organization of permanent public transportation in urban agglomerations in the Russian Federation and abroad is drawn.

Support technology of deep foundation bracing and quality control

Ruibai Times Project lies in the central city area of Jinzhou District, Dalian. With the abundant underwater, the geological condition is quite complex. Underground public transportation, old brick-concrete buildings and converting station are all around the construction site. The deep foundation excavation exceeds 17m. The support design adopts a combination of pile anchor system and internal support, which better solves the problems concerning safety, construction period, and cost. The quality is controlled during the construction process, and the monitoring results show that the support method is safe and reliable.

Land subsidence prediction for a new urban mass rapid transit line in Hanoi

The rapidly increasing population, urbanization, and industrialization of Hanoi city in the last few decades have necessitated the urgent development of a new underground public transport infrastructure such as the urban mass rapid transit (UMRT) system that is now under construction. Simultaneously, concerns on the possible effects of land subsidence on the to-be-constructed and operated UMRT lines must be addressed. One of the difficulties while assessing land subsidence in Hanoi is the insufficient subsidence monitoring data. Therefore, a good geotechnical characterization of the subsoil profile and proper numerical analysis can help predict groundwater pumping-induced subsidence adequately. The UMRT line No. 2 that was selected for this study is special as it runs across the old quarter downtown, located at the very heart of Hanoi city. In this paper, the Hanoi aquifer system, groundwater extraction, and subsidence monitoring network of Hanoi are reviewed comprehensively. Soil data from 30 investigation boreholes were analyzed to characterize the subsoil profile underlying a segment of the UMRT line No. 2 that consists of both elevated and underground sections. Seven soil layers were identified up to a depth of 50 m, including a compressible soft clay layer 10–15 m thick that is supposed to be most vulnerable to subsidence by groundwater pumping. Based on the long-term groundwater monitoring data, one-dimensional finite element method (FEM) consolidation analyses were carried out for three drawdown boundary conditions of 5, 10, and 15 m and yielded a total subsidence of 0.15, 0.35, and 0.5 m, respectively, after 25 years with 1994 as the reference year. The results of this study confirmed that land subsidence in particular should be considered in the construction and maintenance of the UMRT lines in Hanoi, in particular for underground sections that are founded on soft to medium clay layers.

From Piketty’s Capital to Marx’s das Kapital

Thomas Piketty’s book Capital in the Twenty-First Century has created a very new platform for a discussion of the global economy. There is possibly no other book on economy which has been published in so many languages, printed in so many copies, and has found its way to such a varied global public. Piketty’s Capital has been discussed in many high ranked academic journals, and at the same time, it has come out to a broader audience with advertisements in places like the underground public transportation in metropolises around the world. The title of the book is also very ambitious in so far as the title Capital claims to be a follow up of Karl Marx’s Das Kapital for the twenty-first century. Piketty is similar to Marx in his ambition to give a large historical, or a world historical perspective on the significance of capitalist economy for the development of global society. Given this background it could be interesting to consider the relations between Piketty’s Capital and Marx’s Das Kapital.

The significance of the underground experience: Selection of reference design cases from the underground public transport stations and interchanges of the European Union

BackgroundRecent research into the way public transport users appreciate stations and interchanges has highlighted several key aspects. Importantly, the optimization of these facilities should not simply aim to resolve dissatisfiers, but should also focus on addressing satisfiers, through the incorporation of factors such as comfort and experience. ‘Soft requirements,’ which have emerged in architecture and urban design, need to crossover to the urban underground infrastructure (as an element of urban underground space) in order to meet the expectations of public transport users. MethodThis study applies an innovative methodology in the analysis of good practice in urban underground space design, a method more commonly found in cultural studies. Three dimensions in the appreciation of a creative design are considered: views held by the general public; views held by peers (other artists or designers); and views expressed by critics. Using this framework, the article discusses prominent showcases of European underground public transport stations and interchanges, in order to identify design principles that determine a positive user experience of an urban underground space. ResultsA comprehensive overview of good practice with regard to urban underground station design was produced, using reference design cases. The cases included are: Canary Wharf Underground Station; the Georg-Brauchle-Ring Station; Souterrain Tram Tunnel; Triangeln Railway Station; Toledo Metro Station; Fővám Tér Station and Szent Gellért Tér Station (Twin Stations); Chatelet-Les Halles RER Hub; Canary Wharf CrossRail Station; and Birmingham New Street Station. Analysis of these reference design cases (and the good practices involved) allows for the description of ‘satisfying’ design solutions. ConclusionA robust analysis of a well-designed urban underground space can be made based on the opinions of users, peers and critics, through the use of social media, via recognition in prizes and awards and through indexed architectural periodicals. The design principles constituting good practice in underground space design identified in this study are: canopy; open station box; underground morphology and textures; architectural light; intervisibility; art; volume; and proximity.

Radiofrequency electromagnetic radiation exposure inside the metro tube infrastructure in Warszawa

Antennas from various wireless communications systems [e.g. mobile phones base transceiver stations (BTS) and handsets used by passengers, public Internet access, staff radiophone transmitters used between engine-drivers and traffic operators] emitting radiofrequency electromagnetic radiation (RF-EMR) are used inside underground metro public transportation. Frequency-selective exposimetric investigations of RF-EMR exposure inside the metro infrastructure in Warsaw (inside metro cars passing between stations and on platforms) were performed. The statistical parameters of exposure to the E-field were analyzed for each frequency range and for a total value (representing the wide-band result of measurements of complex exposure). The recorded exposimetric profiles showed the dominant RF-EMR sources: handsets and BTS of mobile communication systems (GSM 900 and UMTS 2100) and local wireless Internet access (WiFi 2G). Investigations showed that the GSM 900 system is the dominant source of exposure – BTS (incessantly active) on platforms, and handsets – used by passengers present nearby during the tube drive. The recorded E-field varies between sources (for BTS were: medians – 0.22 V/m and 75th percentile – 0.37 V/m; and for handsets: medians – 0.28 V/m and 75th percentile – 0.47 V/m). Maximum levels (peaks) of exposure recorded from mobile handsets exceeded 10 V/m (upper limit of used exposimeters). Broadband measurements of E-field, including the dominant signal emitted by staff radiophones (151 MHz), showed that the level of this exposure of engine-drivers does not exceed 2.5 V/m.

Fare Design in Urban Transit Network considering Elastic Demand and Adverse Weather’s Impact

Due to the disturbance of unexpected effects and adverse weather conditions, transit supply and demand manifests many uncertainties. In this paper, we take account of these uncertainties and propose a transit fare structure design model including both ground and underground public transportation. Such transit fare design problem is described through bilevel programming, in which the upper level is the transportation authority’s transit fare structure decision aiming to minimize the transit network’s total travel and operation cost, while the lower level is a transit network assignment model considering supply and demand uncertainties that influence passengers’ travel choice decisions. A heuristic algorithm is developed to solve the problem, and a numerical example is presented to illustrate the application. We get some important results: (1) a diversified fare structure considering uncertain weather’s impact is quite necessary; (2) when the value of time is at a high level, metro fare should be higher than bus fare; (3) the optimal metro and bus fare should be close under an extremely adverse weather condition; (4) fare structure could be quite different with varied value of time.

Exposure to PM2.5, Black Carbon and ultrafine particles in above- and underground public transport.

Background: Several studies have shown that particulate matter (PM) concentrations in underground public transport areas such as subway stations are substantially higher compared to outdoor situations. Little is known about how these levels compare to similar above ground locations. Aims: To assess exposure to PM2.5, Black Carbon (BC) and particle number concentrations (PNC) in underground and above ground train and subway transport. Methods: Concentrations of PM2.5, BC and PNC in public transport were measured in two cities in the Netherlands (Amsterdam and Rotterdam) using real-time monitors. In each city, a 3 hour route was traveled twice for 5 non-consecutive days. Each route included at least 15 minutes measurement time in each of the following 8 site categories: underground and above ground train stations, underground and above ground subway stations, underground and above ground trains, and underground and above ground subway vehicles. Results: Concentrations of PM2.5 and BC were significantly higher in each of the four underground site categories compared to the above ground locations. The highest average BC and PM2.5 concentrations were observed in underground train stations (9 and 71 ?g/m3 respectively). BC showed the largest contrasts between sites: Concentrations at underground train stations were 5 times higher compared to above ground levels, and were also 3 times higher compared to levels inside underground train and subway vehicles. Inside vehicles, strong increases and decreases in concentrations were observed when entering or exiting tunnels, and concentrations increased with increasing length of the tunnel. PNC was only significantly elevated at the underground train stations. We estimated that 2 daily 15 minutes commutes in the underground results in an extra daily exposure of 0.35 ?g/m3 (3%) for PM2.5, and 0.06 ?g/m3 (6%) for BC. Conclusion: We found significantly elevated levels of BC and PM2.5 in underground transport locations.

Numerical studies on density jump in a long corridor fire

Many long corridors are built in underground public transport interchanges in downtown of big cities. Smoke control systems have to be installed in these long corridors. A density jump might occur when the smoke flowing under the ceiling hits a smoke barrier. High mass flow rates are then resulted due to additional air entrainment. In this paper, characteristic of density jump at smoke barrier in long corridors, which are induced by horizontal smoke movement underneath the ceiling, will be studied by Computational Fluid Dynamics (CFD). Three fire scenarios LF1, LF2 and LF3 with 3MW, 5MW and 10MW fires are selected in a long corridor with two smoke barriers to study the characteristic of density jump. Predicted results by CFD are discussed and compared with the analytical expressions about density jump. As the Froude number under normal fire condition is relatively low, other scenarios HF1–HF3 with higher Froude number were carried out. All CFD results further confirm that density jump occurs when smoke flowing in a long corridor strikes the smoke barrier. Air entrainment would be increased and this phenomenon should be included in fire hazard assessment of long corridor.

Investigations on air currents in underground public transportation systems

Sufficient knowledge about the underground field of airflow, and the interdependencies with the outer atmosphere is urgently needed to allow for quick evacuation and safety measures to be applied in emergency situations. In case of a fire or a terror attack, respectively, the trains will have to stop, which will cause the spreading ways of pollutants to adjust to the background current, which in turn is then uninfluenced by train movements. However, information about airflow conditions in underground public transport systems and the factors that are influencing these directly is scarce. It has to be assumed that the underground field of currents is governed by extremely complex and highly variable factors such as the previous and the actual weather conditions; it is thus correspondingly variable and flexible. This means that it is important to investigate the background airflow to identify the respective underlying principles. The investigation presented here shows impressively that a distinct background current can develop inside an underground public transportation system: Short intervals between trains that run opposed to the direction of currents can alternate and modify this background current in so far that it is reversed into the opposite direction; thus, in this situation, the background current cannot be identified as such any more. This is the key to the problem of two opposing directions of current inside one single station. However, this situation cannot be used to develop a primer rule for underground systems: Position of tracks and platforms inside the stations, and the routing of tracks inside the tunnels play an important role with respect to this problem. However, the dependency of such an underground system on the weather conditions outside could not be quantified yet; measurements with the aim to identify and quantify such dependencies have already started.

Appraisal of underground urban public transportation projects

Abstract The authors examine the decision-making process for urban mass transit systems and ways of evaluating underground transportation projects. The article begins by answering three integral qusetions: (1) What different parties are involved in the project? (2) Why is it necessary to appraise such projects? (3) What should the appraisal consist of? Appraising mass transit projects involved assessing various aspects of the project, and expressing the results in monetary terms, quantitative evaluations and/or verbal (qualitative) explanations. The two methods of appraising projects in France—one, applied to projects in the Greater Paris region; the other, to projects in the provincial cities—are described and discussed. Finally, specific considerations in evaluating underground vs aboveground mass transit projects are discussed.

State Feedback Traffic Control of the Transient Behaviour of Underground Public Transportation Systems

Abstract This paper proposes two methods of traffic regulation of public underground transportation systems during transients, for example during the modification of the intervals between the trains. Both methods are based on optimal control theory for linear systems with quadratic criterion. In the first approach the system is controlled with respect to a new nominal time schedule to be generated accordingly to the new situation while the second method realizes interval control without reference to a nominal schedule. The properties of both methods are analyzed and simulation results are discussed and compared.