4,171 research outputs found

    Improving Pathways to Transit for Persons with Disabilities

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    Persons with disabilities can achieve a greater degree of freedom when they have full access to a variety of transit modes, but this can only be achieved when the pathways to transit – the infrastructure and conditions in the built environment – allow full access to transit stops, stations, and vehicles. Since passage of the Americans with Disabilities Act (ADA) in 1990, many transit agencies and governmental jurisdictions have made significant progress in this area. Policy initiatives, incremental enhancements, modifications, and other measures undertaken by transit agencies and their partners have significantly improved access to transit for persons with disabilities, others who rely on public transportation, and individuals who chose to utilize these services. This research study explores, through case study work, efforts that have been effective in improving pathways to transit. Interviews and site visits were conducted with five transit agencies, along with their partners, that are actively engaged in improving pathways to connect transit consumers – particularly people with disabilities – with transit stations and stops. These agencies are: Broward County Transit (Broward County, FL), Memphis Area Transit Authority (Memphis, TN), NJ TRANSIT (Newark and New Brunswick, NJ), Tri-County Metropolitan Transportation District of Oregon (Portland, OR), and Link Transit (Wenatchee, WA). Promising practices and/or lessons were identified through the case study analysis; these should be considered by any transit agency seeking to create improved access to its services for persons with disabilities

    Cable Propelled Gondola System Operation in Icing Conditions

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    The scope of this study comprehends problems associated with modern urban vehicles known as cable propelled gondolas system operations in icing conditions. The aspects under consideration are problems related to the operations, safety, and maintenance of cable car systems in harsh climate conditions. The geographical location of the gondola cars makes them vulnerable to severe weather conditions especially in cold climates of the northern hemisphere, where icing on its components is an operational, maintenance, and safety concern. The harsh climate conditions can cause unadorned malfunctions posing a threat to the integrity the of system as well as a high risk to human safety. The study basis on the identification of these problems in operational, maintenance and safety domain including implications the industry faces in the form of severe accidents costing precious lives and lost capital. Furthermore, it incorporates the ice detection, anti/de-icing approaches as well as the safety strategies in use nowadays. The massive increase in operations and dynamic climate conditions gondola cars require serious attention. This study unsheathes serious underlying problems that severely affect the gondola operations, makes them prone to major maintenance shutdowns and poses high risk to structural and human safety. The identified problems in this study and severity of risks draw attention to need for practicable solutions incorporating de-icing and ice removal techniques for safe operation of gondolas in cold climates saving time, effort, inconvenience, and prodigious lost capital

    Numerical study on aerodynamic characteristics of high-speed trains with considering thermal-flow coupling effects

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    In order to conduct in-depth researches on rationality of air conditioning system equipment of a high-speed train as well as its pipeline system design, working conditions of the air conditioning system and distribution of aerodynamic characteristics including pressure, velocity and temperature in high speed trains should be computed carefully at the design stage. Therefore, the finite volume method was used to solve a governing equation of computational fluid dynamics. The aerodynamic characteristics of pipelines of the air conditioning system and the complete high speed train were computed, so the indoor distribution of wind velocity, temperature and gas concentration (carbon oxide, carbon dioxide, nitrogen and so forth) was obtained. The flow field index and the thermal comfort index were used to evaluate the indoor thermal comfort degree. In this way, whether rationality of the air conditioning system design and indoor aerodynamic characteristic could satisfy requirements for design specifications can be analyzed. Results show that: Under winter or summer working conditions, wind velocity was relatively high at the passageway door, where the maximum wind velocity was more than 1 m/s and would make passengers uncomfortable. Air flow velocity outside comfortable regions was more than 0.05 m/s, satisfying UIC553 standards. Velocity distribution was basically the same indoors, where wind velocity was large at positions perpendicular to the air supply hole, and the maximum wind velocity was more than 1 m/s, but wind velocity was uniform in the passenger region, which was basically lower than 0.2 m/s and satisfied UIC553 standards. In summer and winter working conditions, distribution of pressure, velocity and temperature was not uniform, where the maximum temperature gradient was near the air inlet in the compartment. Air components in the compartment satisfied requirements for comfort. The most uncomfortable regions in the compartment were concentrated at the passageway. Air supply holes distributed symmetrically on the train roof caused high air flow intensity, high wind velocity, low temperature and high humidity at the passageway in the compartment, so the thermal comfort was low, and it is feasible to adjust the layout of air supply holes appropriately

    Utilization of evacuation model for airports using risk based fire safety scenario

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    This report focuses the use of egress models to study the airport evacuation with special focus on security doors in case of total evacuation in airport terminal buildings. Case studies are made in arrival hall and departure hall of the airport terminal based on the scenarios identified in a preliminary risk analysis carried out in the terminal. Evacuation strategies are employed in the two different cases to study the evacuation based on the one way flow and counter-flow through security doors. This report presents the generalized method of designing an airport terminal based on the design peak hour passengers and the risk based fire safety method to identify the high fire risk locations with respect to the occupant evacuation safety. The evacuation strategies have been modeled in two simulation software tools (Pathfinder and LegionEvac) to compare the total evacuation time. The comparison between the models is discussed based on the total evacuation time. Based on the evacuation time, further evacuation strategies are simulated to study the flow pattern and evacuation problems with respect to airport environment. In the result section, critical factors which affect the airport evacuation and suggestion for optimization is discussed

    Improving the energy efficiency of high speed rail and life cycle comparison with other modes of transport

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    The world energy crisis and global warming call for a reduction of energy consumption. High speed rail, increasingly viewed as an effective solution to inter-city passenger transportation challenge of the 21st century, has the significant ability of increasing passenger capacity and reducing journey time. The advent of high speed rail provided many research opportunities. So far studies have been contributed from different perspectives: economical, environmental, and technical. The main research gaps are: addressing the problem of the effects of route geometry on train energy consumption and quantifying the contributing factors towards differences in energy consumption between different types of high speed trains. In addition, this energy assessment cannot be based solely on the energy consumption in the operation phase. In the life cycle assessment of the whole railway system, the vehicle evaluation is relatively straightforward, but the infrastructure raises many difficult issues. In this thesis, an existing approach for modelling the traction energy of electric trains is developed and extended to simulate the train operation under different driving strategies. Baseline simulation is carried out to estimate the journey time and energy consumption of a High Speed 2(HS2) reference train running on the London-Birmingham proposed high speed route. The influence of route geometry and train configuration on energy consumption is investigated, based on the metric of energy consumption per passenger kilometre. Simulations are also carried out of different types of high speed rolling stock running on the proposed HS2 route, to identify the key areas of vehicle design which help to minimise the energy consumption of high speed rail travel. The life cycle assessment of railway infrastructure is carried out in four stages of a whole life cycle: production, operation, maintenance and disposal, the influence of route parameters on life cycle cost is also investigated. Finally, high speed rail is compared with competing modes of transport, i.e. the aircraft, the automobile and the conventional train, in both operational energy efficiency and whole life cycle analysis. The high speed rail transportation has great advantage over the road and air transport, giving a reduction of carbon emission by roughly 95%, among which the operation stage contributes the largest reduction.Open Acces

    Impact of building sway on in-car vibration of ultrahigh-rise elevators — multiphysics simulation approach

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    High-rise, high-speed elevators are subjected to both static and dynamic loads. They are transferred into the elevator and perceived as in-car vibrations. Building sway is one of the main contributors to in-car vibration for high-rise elevators. Vibrations transferred into the elevator is greatly influenced by the response of building sway amplitudes. A finite element model of the elevator was developed using ABAQUS/Standard. Transient dynamic simulation method was utilized to compute the in-car vibrations. Various subroutines were used to include the installation inaccuracies over the travel distance. Aerodynamic loads calculated using computational fluid dynamics were used in the finite element model as pressure loads acting over a specified time interval. Finite difference method was used to study the rope behavior for different building sway amplitudes and elevator speed profiles. The rope forces calculated using this method is extracted and applied in the finite element simulation. The output of each computations is expressed as in-car vibration amplitudes. This thesis mainly focuses on the prediction of in-car vibration due to building sway for a specific elevator configuration. Human perception of the vibration and the discomfort caused to the passengers because of the in-car vibration is investigated. Finally, the thesis proposes an optimized speed profile approach to mitigate this problem. 51 combinations of various building sway amplitude and speed profiles are computed using finite element method. Multiple regression model function is developed by curve fitting and validated against the test data. The generated function helps to predict the optimized speed profile that needs to be followed in order to maintain the required ride comfort. Also, the benefits of optimized speed profile is demonstrated by using handling capacity assessment calculations

    Exploring Data Driven Models of Transit Travel Time and Delay

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    Transit travel time and operating speed influence service attractiveness, operating cost, system efficiency and sustainability. The Tri-County Metropolitan Transportation District of Oregon (TriMet) provides public transportation service in the tri-county Portland metropolitan area. TriMet was one of the first transit agencies to implement a Bus Dispatch System (BDS) as a part of its overall service control and management system. TriMet has had the foresight to fully archive the BDS automatic vehicle location and automatic passenger count data for all bus trips at the stop level since 1997. More recently, the BDS system was upgraded to provide stop-level data plus 5-second resolution bus positions between stops. Rather than relying on prediction tools to determine bus trajectories (including stops and delays) between stops, the higher resolution data presents actual bus positions along each trip. Bus travel speeds and intersection signal/queuing delays may be determined using this newer information. This thesis examines the potential applications of higher resolution transit operations data for a bus route in Portland, Oregon, TriMet Route 14. BDS and 5-second resolution data from all trips during the month of October 2014 are used to determine the impacts and evaluate candidate trip time models. Comparisons are drawn between models and some conclusions are drawn regarding the utility of the higher resolution transit data. In previous research inter-stop models were developed based on the use of average or maximum speed between stops. We know that this does not represent realistic conditions of stopping at a signal/crosswalk or traffic congestion along the link. A new inter-stop trip time model is developed using the 5-second resolution data to determine the number of signals encountered by the bus along the route. The variability in inter-stop time is likely due to the effect of the delay superimposed by signals encountered. This newly developed model resulted in statistically significant results. This type of information is important to transit agencies looking to improve bus running times and reliability. These results, the benefits of archiving higher resolution data to understand bus movement between stops, and future research opportunities are also discussed

    High-speed civil transport flight- and propulsion-control technological issues

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    Technology advances required in the flight and propulsion control system disciplines to develop a high speed civil transport (HSCT) are identified. The mission and requirements of the transport and major flight and propulsion control technology issues are discussed. Each issue is ranked and, for each issue, a plan for technology readiness is given. Certain features are unique and dominate control system design. These features include the high temperature environment, large flexible aircraft, control-configured empennage, minimizing control margins, and high availability and excellent maintainability. The failure to resolve most high-priority issues can prevent the transport from achieving its goals. The flow-time for hardware may require stimulus, since market forces may be insufficient to ensure timely production. Flight and propulsion control technology will contribute to takeoff gross weight reduction. Similar technology advances are necessary also to ensure flight safety for the transport. The certification basis of the HSCT must be negotiated between airplane manufacturers and government regulators. Efficient, quality design of the transport will require an integrated set of design tools that support the entire engineering design team
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