The carbody plays an important role in rail vehicle dynamics.This thesis aims atdeveloping validated modelling methods tostudy its dynamics, how it is excited on trackand how itinteracts with the passengers. The primary interest is ridecomfort,considering vibrations up to 20 Hz. In this frequencyrange, the structural flexibility ofthe carbody is of majorconcern. The models are intended for use intime-domainsimulation, calling for small-sized models to reducecomputational time and costs. Keyparameters are proposed toselect carbody eigenmodes for inclusion in a flexiblemultibodymodel, and to quantify the interaction between passengers andcarbody. Extensive comparisons between measurements and correspondingsimulations arecarried out in a case study. On-track measurementsare performed to obtain operatingdeflection shapes and powerspectral densities of the accelerations in the carbody.Thecomplete vehicle is modelled using the pieces of softwareGENSYS (flexible multibodymodel) and ANSYS (finite element modelof the carbody). Actual, measured trackirregularities are used asinput. In order to investigate the influence of passengerload,experimental modal analysis of the carbody is performed withand without passengers.Also, amplitude dependence is examined.Simple models, based on human-body modelsfrom literature, of thepassenger-carbody system are proposed and validated.Verticalseating dynamics is considered. The models areimplemented and tested in the casestudy. Finally, ideas on modelreduction and approximation are presented and applied. The main conclusions drawn from the study are that     the structural flexibility of the carbody must be takeninto account when predictingvertical vibration comfort. It ispossible to predict which carbody modes that willcontributemost to the vibrations.     the carbody dynamical properties depend on the excitationamplitude.     passengers and carbody interact significantly.- theproposed models describe the interaction quite well. Theproposed passenger-carbodymodel gives an upper boundary on theinteraction.     the proposed passenger-seat-carbody model can be used tostudy the influence of theseat parameters on the interaction.This merits to be investigated further, however. <b>Keywords</b>: Carbody, Experimental modal analysis, Human-bodydynamics, Modelreduction, Multibody dynamics, Operatingdeflection shapes, Rail-vehicle dynamics,Ride comfort, Seatingdynamics, Structural dynamics.

Mass transit in the form of light rail is, in many ways, a new and revolutionary idea for the Greater Los Angeles Area. Although mass light rail transit did exist in Los Angeles in the form of the Pacific Electric Railways red car system, an extensive network of metro rail lines has never existed in Los Angeles County since Pacific Electric was dismantled and shut down in 1950. Because of this, the popular mode of transport in LA County has traditionally been cars, and public transport has consisted mostly of bus routes. This has all changed in the last few decades. Since the 1980s, LA County has conducted several studies and, as a result of those studies, has proposed to build an extensive network of light rail lines to connect the county. In more recent years, many of these project plans have been approved, and the MTA has overseen the construction and functioning of new railway lines that are connecting far-flung regions of LA County with Union Station in downtown LA. Currently, the MTA operates 5 light rail lines within LA county-the Blue Line, the Red Line, the Purple Line, the Green Line and the Gold Line-that extend north, south and east of downtown LA. Each of these lines has been functional for a varying amount of time, but current weekday ridership on this system of lines has crossed the 280,000 mark as off September 2009.

<p>The carbody plays an important role in rail vehicle dynamics.This thesis aims atdeveloping validated modelling methods tostudy its dynamics, how it is excited on trackand how itinteracts with the passengers. The primary interest is ridecomfort,considering vibrations up to 20 Hz. In this frequencyrange, the structural flexibility ofthe carbody is of majorconcern. The models are intended for use intime-domainsimulation, calling for small-sized models to reducecomputational time and costs. Keyparameters are proposed toselect carbody eigenmodes for inclusion in a flexiblemultibodymodel, and to quantify the interaction between passengers andcarbody.</p><p>Extensive comparisons between measurements and correspondingsimulations arecarried out in a case study. On-track measurementsare performed to obtain operatingdeflection shapes and powerspectral densities of the accelerations in the carbody.Thecomplete vehicle is modelled using the pieces of softwareGENSYS (flexible multibodymodel) and ANSYS (finite element modelof the carbody). Actual, measured trackirregularities are used asinput. In order to investigate the influence of passengerload,experimental modal analysis of the carbody is performed withand without passengers.Also, amplitude dependence is examined.Simple models, based on human-body modelsfrom literature, of thepassenger-carbody system are proposed and validated.Verticalseating dynamics is considered. The models areimplemented and tested in the casestudy. Finally, ideas on modelreduction and approximation are presented and applied.</p><p>The main conclusions drawn from the study are that</p><p>    the structural flexibility of the carbody must be takeninto account when predictingvertical vibration comfort. It ispossible to predict which carbody modes that willcontributemost to the vibrations.</p><p>    the carbody dynamical properties depend on the excitationamplitude.</p><p>    passengers and carbody interact significantly.- theproposed models describe the interaction quite well. Theproposed passenger-carbodymodel gives an upper boundary on theinteraction.</p><p>    the proposed passenger-seat-carbody model can be used tostudy the influence of theseat parameters on the interaction.This merits to be investigated further, however.</p><p><b>Keywords</b>: Carbody, Experimental modal analysis, Human-bodydynamics, Modelreduction, Multibody dynamics, Operatingdeflection shapes, Rail-vehicle dynamics,Ride comfort, Seatingdynamics, Structural dynamics.</p>

This report explores the long-term demographic changes occurring near Dallas Area Rapid Transit (DART) stations. The study area chosen to employ the shift share method consists of two segments of DART stations along the Red Line in Dallas, Texas. The downtown DART study area consists of census tracts surrounding light rail stations: Cedars, Convention Center, Union Station, West End, Akard, St. Paul, and Pearl, and the DART suburban study area consists of census tracts around the following stations: City Place, Mockingbird Station, Lovers Lane, Park Lane, Walnut Hill, Forest Lane, and LBJ/Central. Using the shift share method with demographic data obtained through the US Census Bureau from 1990 and 2005-2009 American Community Survey estimates, this analysis illustrates demographic changes over time as a result of light rail transit investments. The results indicate that demographic characteristics of residents have changed considerably since the introduction of light rail in Dallas. Although the growth trends in the DART neighborhoods are comparable to the growth trends of the city, the DART census tracts on average have experienced greater increases in population, attracted an influx of highly educated residents with higher household incomes, and experienced significant increases in high-density development surrounding transit stations. For the most part, growth has been stronger locally than on a citywide level, and these trends have occurred most noticeably in the downtown DART neighborhoods, where transit and financial measures have sparked a development boom in which total population and housing units have grown by the hundredth and even thousandth percentile. Additionally, these demographic changes create unintended consequences that affect people of varying socio-economic statuses. Although the shift of highly educated, wealthier individuals in neighborhoods creates a greater social mix among residents, lower-income residents of these transit neighborhoods quickly get priced out of their neighborhoods. / text

The 4-step process has been the standard procedure for transit forecasting for over 50 years. In recent decades, researchers have developed ridership forecasting regression models as alternatives to the costly and time consuming 4-step process. The model created by Lane, DiCarlantonio, and Usvyat in 2006 is among the most recent and most widely accepted. It includes station area demographics, central business district (CBD) employment, and the station areas’ built environments to estimate ridership. This report applies the Lane, DiCarlantonio, and Usvyat model to the North Line of Houston’s Metropolitan Transit Authority of Harris County (METRO). The report compares the 2030 ridership forecast created by METRO using the 4-step process with the LDU model forecasts. For the 2030 projections, this report obtained population and employment estimates from the Houston-Galveston Area Council and analyzed the data using Esri ArcMap and Caliper TRANSCadGIS software programs. The LDU model produced unrealistically high ridership numbers for the North Line. It estimated 108,430,481 daily boardings. METRO’s 4-step process predicted 29,900 daily boardings. The results suggest that the LDU model is not applicable to the Houston light rail system and is not a viable alternative to the 4-step process for this specific metropolitan area. The LDU method for defining Houston’s CBD was the main problem in applying the model. It calculated an extremely high CBD employment density compared to other cities of similar size. Even when the CBD size was manipulated to decrease employment density, the model still predicted 212,210 daily boardings for the North Line, nearly 10 times higher than METRO’s 4-step process estimate. In addition to the problems with the definition of the CBD, the creators of the LU model did not specifically explain how to define a metropolitan area. Multiple inconsistent and subjective definitions of a metro area can be used. This report employs three different definitions of the Houston metro, all of which produced three significantly different ridership forecasts in the LDU model. As a result of these flaws, the LDU model does not accurately apply to METRO’s North Line, and it does not serve as a viable alternative to METRO’s 4-step process. / text

This paper seeks to determine how the elements of true Transit-Oriented Development (TOD) can successfully be implemented in a suburban setting. The author establishes firm criteria for creating successful TOD. These criteria are then used to evaluate both TOD and neighborhood plans for case study sites in the Austin, TX metropolitan area. The paper completes this evaluation by pointing out synergies, discrepancies and offering recommendations for improvement, based on the case studies. / text

Influence of built environment on travel behavior has been recognized by several studies in last decade (Cervero 2003, 2004, Ewing at al 2003 and etc.). Easy access to the transit station and mixed land use has been largely emphasized by New Urbanist because of its influence on transit ridership and reduction of vehicle mile travel. However, empirical evidence that proximity of residential location to the transit station or mixed land use reduces auto dependency and encourages transit ridership has been lack for Chicago metropolitan region in spite of its long history of transit development. This study uses 2007 Chicago metropolitan region travel tracking study data and travel characteristics of residents living within walkable distance from the CAT or METRA rail station in Chicago Metropolitan region was analyzed in comparison with those of residents living beyond walkable distance from the rail station in order to find any difference in socio-demographic characteristics and travel characteristics. In general, households located within walkable distance (a quarter mile for this study) from the rail station are more likely to be low income households, to reside in a multifamily rental housing. Residents living within walkable distance show higher portion of African American or Asian proportion, of smaller-sized households (a single member household or childless household). They are likely to own fewer cars than residents living far from the rail station. With this observation of some difference in sociodemographic and travel characteristics between two groups, probability of transit use and rail use in a relationship with home location and job location were tested using binary logistic model. The result indicates that the number of household vehicles per person in the household influences negatively on residential location. The more available household cars per person, the less likely it is that a household is located within walkable distance from the rail station. Work location was also an important factor for transit or rail use. This provides evidence that providing mixed land use where jobs and housing are all provided within walkable distance from the transit station can increase transit use and reduces auto-dependency that current American society is facing severely. / text

Travel time has generally been regarded as an unproductive period, representing a means-to-an-end in order to engage in activities at specific destinations. Rapid developments in mobile technology have provided people with innovative ways to multi-task and engage in meaningful activities while travelling. Rail transportation specifically, offers passengers advantages over other means of transportation as there is no need to focus on driving tasks. Due to the increase in passenger numbers and limited seating availability in train carriages, over one third of rail passengers are required to stand while travelling (DfT, 2013). The vibration to which rail passengers are exposed has been shown to interfere with the performance of activities and for standing passengers, it is often necessary to use postural supports such as holding on to grab rails or leaning on walls in order to maintain stability. The overall aim of the research is to evaluate the influence of whole-body vibration (WBV) exposure and standing posture on the performance of manual control tasks and the associated subjective workloads experienced by rail passengers. The use of supports, such as a backrest in seated postures, has been found to influence the response of the human body to WBV exposure, yet no reported studies have investigated the effects of postural supports on the response of the body in standing postures. Understanding how the body is affected in these conditions would increase the current state of knowledge on the biomechanical responses of the human body to vibration exposure and provide improved representation of standing postures within vibration standards (for example, ISO2631-4 (2001)) and guidelines for device interface design. A field study, using direct observation, was conducted to assess the behaviour of standing rail passengers and determine the characteristics of typical vibration exposures. This information provided the basis for the design of four subsequent laboratory studies. The main investigations of the laboratory studies were the influence of WBV exposure on objective performance measures, such as task completion time and error rate, and subjective workloads (for example, NASA TLX) for a range of manual control tasks. One of these laboratory studies evaluated the influence of various postural supports (for example, backrests) on the biomechanical responses of standing individuals. Measurements obtained during the field investigation indicated that the vibration exposures did not exceed the EU Physical Agents Exposure Action Value (EAV) and therefore posed little risk of injury. Vibration magnitudes in the horizontal directions (x- and y-axes) were higher than in the vertical direction (z-axis) and it was necessary for standing passengers to alter behaviours and use supports in order to maintain stability while travelling. The results of the laboratory studies indicated that in conditions where decrements in task performance occurred, the extent to which performance was degraded increased progressively with increases in vibration magnitude. There were conditions (for example, in the continuous control task and the Overhead Handle supported posture in the serial control task) where vibration exposure showed no significant influence on performance measures. This suggested that individuals were able to adapt and compensate for the added stress of vibration exposure in order to maintain performance levels however, this occurred at the expense of mental workload. The workload experienced by the participants increased with corresponding increases in magnitude. Vibration frequency-dependent effects in performance and workload were found to match the biomechanical responses (apparent mass and transmissibility) of the human body and resemble the frequency weightings described in the standards (ISO2631-1 (1997)). During the serial control task, the postures which demonstrated the greatest decrements to performance (for example, Lean Shoulder and Lean Back ) corresponded to the same postures that showed the greatest influence on the biomechanical responses of the body. It was concluded therefore, that measurements of the biomechanical responses to WBV could be used to offer predictions for the likelihood of activity interference. Consideration should however, be given to the applicability of this research before these results can be generalised to wider contexts. Further validation is recommended for future work to include different conditions in order to substantiate the findings of this research.

Railguns undergo excessive wear between the projectile and the electromagnetic launcher rails due to the hypersonic relative motion and very large current density involved. The wear effects at the small-scale on the rail-armature interface are not well known but need to be examined in order to support the development of a multishot launcher. Proposed contact regimes in the surface asperity interactions include solidsolid contact, liquid-metal lubricated contact, and arcing. In the present work, a modified Mesoscale Friction Tester (MFT) equipped with a probe and substrate was used to investigate experimentally the arcing and friction conditions that the rail-armature interface would experience. Copper probes with a range of radii of curvature were electrochemically etched and polished to submicrometer roughness. The minimum electrode distances for arcing to occur was found in air at atmospheric pressure and led to a modified Paschen curve where field emission of electrons was the dominant physical mechanism as opposed to Townsend avalanche of ionized gas. Arcing erosion was studied by varying the current, number of strikes, dwell time, and nearest electrode positions horizontally and vertically. Copper-copper friction with a constant normal force resulted in reduced wear when applying a constant current between the electrodes. / text

Highway/railroad grade crossings present a danger to vehicular traffic. According to the USDOT Bureau of Transportation Statistics, in 2009, there were 1,887 crashes at highway/rail crossings resulting in 248 fatalities (FRA, 2009). The installation of presignals at grade crossings decreases crashes and fatalities at highway/rail crossings. There are no Federal standards that provide guidance for the installation of presignals. Therefore, current practices do not conform to any set of consistent nationwide standards except for guidelines specified in the MUTCD. These guidelines state that a presignal should be considered where the at-grade highway/rail crossing is located within 50 feet of a signalized intersection. The MUTCD also gives the option of installing a presignal at a distance greater than 50 feet, if an engineering study determines a need; however, no specific guidelines are provided for such studies.This work uses a case study to determine which measures are needed to warrant a presignal and examines if the distance criterion of 50 feet between signalized intersections and highway/rail crossings is adequate. It also explores the need for consistent national standards to provide guidance to practitioners in determining the needs for the installation of such signals.The study finds that distance criterion should not be used as the sole indicator for the installation of a presignal and therefore, engineering studies must be performed in all cases to determine presignal needs. Furthermore, the work concluded that the MUTCD must be modified to provide standards and guidelines that can be used nationwide for systematic quantitative assessment in determining when presignals are warranted near railroad crossings. This study proposes that presignals be installed based on warrants that consist of crash data, queue distance and no gates at the crossing. The proposed modifications include describing presignal types, defining their purpose, developing presignal warrants, and creating guidelines that can be used by practitioners.The changes and revisions recommended by this research work include queue length analysis, signal phasing and timing modifications, and existing intersection infrastructure needs. The resulting warrants and guidelines for presignal installation can be used nationally to provide uniform guidance and recommendations in performing presignal studies.