One way to make rail vehicles a competitive means of transportation is to increase running speed. However, higher speeds usually generate increased forces and accelerations on the vehicle, which have a negative effect on ride comfort. With conventional passive suspension, it may be difficult to maintain acceptable passenger comfort. Therefore, active technology in the secondary suspension can be implemented to improve, or at least maintain, ride comfort at increased vehicle speeds or when track conditions are unfavourable. This thesis describes the development of an active secondary suspension concept to improve ride comfort in a high-speed train. Firstly, an active lateral secondary suspension system (ALS) was developed, including dynamic control of the lateral and yaw modes of the carbody. Furthermore, quasi-static lateral carbody control was included in the suspension system in order to laterally centre the carbody above the bogies in curves at high track plane acceleration and hence to avoid bumpstop contact. By means of simulations and on-track tests, it is shown that the ALS system can offer significant lateral ride comfort improvements compared to a passive system. Two different control strategies have been studied—the relatively simple sky-hook damping and the multi-variable H∞ control—using first a quarter-car and then a full-scale vehicle model. Simulation results show that significant ride comfort improvements can be achieved with both strategies compared to a passive system. Moreover, H∞ control in combination with the carbody centring device is better at reducing the relative lateral displacement in transition curves compared to sky-hook damping. Secondly, an active vertical secondary suspension system (AVS) was developed, using simulations. Dynamic control of the vertical and roll modes of the carbody, together with quasi-static roll control of the carbody, show significant vertical ride comfort improvements and allow higher speeds in curves. Further, the AVS system compensates for negative ride comfort effects if the structural stiffness of the carbody is reduced and if the vertical air spring stiffness is increased. Finally, the two active suspension systems (ALS and AVS) were combined in simulations. The results show that both lateral and vertical ride comfort is improved with the active suspension concept at a vehicle speed of 250 km/h, compared to the passive system at 200 km/h. Further, active suspension in one direction does not affect the other direction. The ALS system has been included in two recent orders comprising more than 800 cars. / QC 20111205 / Gröna Tåget

One of the principal energy absorbing structural components that influences the crashworthiness of a vehicle is the side-rail, which is also commonly referred to as an s-rail due to its shape that is reminiscent of an “s”. To improve the crashworthiness of a vehicle, in the wake of significant environmental pressures requiring vehicle light-weighting, the parameters that govern the crash response of the s-rail and the implications of light-weight material substitution need to be better understood. In this work, the main parameters that govern the crash response of an s-rail and the variables that influence them were identified and assessed through a combined experimental and numerical modelling programme. In particular, the as-formed properties of aluminium alloy s-rails, due to the tube bending and hydroforming fabrication route were examined. Tube bending, hydroforming and crash experiments were conducted to examine and assess the effects of initial tube thickness, strength, geometry, bend severity, work hardening, thickness changes and residual stresses on the crash response of the s-rail. The forming process variables, springback, thickness, strains, and force and energy response measured in the experiments were used to validate the finite element models developed herein. The validated numerical models of tube bending, hydroforming and crash provided additional insight and also allowed further investigation of the parameters governing the crash response of s-rails. The relevant parameters governing the crash response of s-rails were isolated and the basis for a set of design guidelines, in terms of maximizing energy absorption or minimizing mass, was established. The overall size is the most influential design parameter affecting the energy absorption capability of the s-rail, followed by the initial thickness, material strength, cross-sectional geometry, bend severity and hydroforming process employed, and finally boost in bending. The most significant conclusion made based on this research is that the effects of forming history must be considered to accurately predict the crash response of the s-rail. There are additional conclusions with respect to the tube bending and hydroforming processes, as well as s-rail crash response, that will contribute to improving the design of s-rails for better crashworthiness of vehicles.

One of the principal energy absorbing structural components that influences the crashworthiness of a vehicle is the side-rail, which is also commonly referred to as an s-rail due to its shape that is reminiscent of an “s”. To improve the crashworthiness of a vehicle, in the wake of significant environmental pressures requiring vehicle light-weighting, the parameters that govern the crash response of the s-rail and the implications of light-weight material substitution need to be better understood. In this work, the main parameters that govern the crash response of an s-rail and the variables that influence them were identified and assessed through a combined experimental and numerical modelling programme. In particular, the as-formed properties of aluminium alloy s-rails, due to the tube bending and hydroforming fabrication route were examined. Tube bending, hydroforming and crash experiments were conducted to examine and assess the effects of initial tube thickness, strength, geometry, bend severity, work hardening, thickness changes and residual stresses on the crash response of the s-rail. The forming process variables, springback, thickness, strains, and force and energy response measured in the experiments were used to validate the finite element models developed herein. The validated numerical models of tube bending, hydroforming and crash provided additional insight and also allowed further investigation of the parameters governing the crash response of s-rails. The relevant parameters governing the crash response of s-rails were isolated and the basis for a set of design guidelines, in terms of maximizing energy absorption or minimizing mass, was established. The overall size is the most influential design parameter affecting the energy absorption capability of the s-rail, followed by the initial thickness, material strength, cross-sectional geometry, bend severity and hydroforming process employed, and finally boost in bending. The most significant conclusion made based on this research is that the effects of forming history must be considered to accurately predict the crash response of the s-rail. There are additional conclusions with respect to the tube bending and hydroforming processes, as well as s-rail crash response, that will contribute to improving the design of s-rails for better crashworthiness of vehicles.

With this dissertation, it is intended to improve our understanding of the effects of urban rail systems on the mobility of women, their accessibility and their extent of experiencing the city they live in, that is their urban geography. The main aim is to understand whether women who live nearby an urban rail system and who use this system have higher levels of mobility and wider urban geography when compared with those who live in places without an urban rail access and those who do not use urban rail systems. In search for the effects of metro usage on mobility, as well as the factors affecting metro usage, the study is built on four main fields in transportation studies: mode choice theory, activity based travel theory, time-geography theory and women studies. Women living on Ankara metro line and in Ke&ccedil / i&ouml / ren constitute the main case study in this thesis. With the help of a comprehensive questionnaire, applied on captive public transport women riders, it is assessed whether the Ankara metro has positive effects on the mobility of women living nearby the metro stations, whether women who use the metro have higher mobility and wider urban geography, and whether the metro can be effective in enhancing the mobility and urban geography of women who are identified as particularly vulnerable in the literature. Understanding the factors, in cases where expected positive impacts on mobility have not been realized, is also important to contribute to the theoretical discussions that the study is built on.

Rail transit investments require highest amount of investment costs of all modes and considering the high cost involved, it is particularly important that their performance justifies this high cost and that expectations from these investments are met. Therefore, in the world, it has become an important field of research to study the performances of rail systems in order to assess whether these expectations are met. In Turkey, there is a growing interest in constructing rail transit systems in the cities. However, there has been limited number of studies on the performance of these investments. There are researches on individual systems / yet, there has not been a comprehensive, systematic and comparative evaluation of the rail transit experience of Turkish cities. It is not clear with what expectations these systems are built or whether these expectations are met. There seems to be an urgent need to study these rail investments, with a particular focus on their planning, investment objectives and outcomes. This thesis analyzes the expectations from the rail transit systems in Turkey and answers the question whether these expectations are met. In order to understand the objectives under the planning and decision making processes in the implementation of Turkish rapid rail transport investments, a sample group was selected among the cities currently operating rail transit systems: &amp / #272 / stanbul, Ankara, &amp / #272 / zmir and Bursa. The study sets the objectives in planning and implementing rail transit systems drawn by the answers in the semi-structured interviews. It compares the expectations with the actual outcomes. As the primary indicators of performance, cost and ridership forecast and outcome data are also collected and considered in the comparison. It is found that the main success in all case study cities was the increase in public transport usage after the opening of the rail transit systems. On the other hand, systems performed rather poor in terms of other expectations, such as attaining ridership forecasts, being built within budget, creating an integrated public transport system, traffic reduction, air pollution reduction, improvement of city image, etc. Hence there is a gap between expectations and outcomes.

Das lauftechnische Verhalten von Schienenfahrzeugen ist fahrzeugseitig geprägt von Eigenschaften, die im Wesentlichen aus der Spurführung, den bewegten Massen, Geometrien und aus der Federungs- und Dämpfungscharakteristik des Fahrzeugs herrühren. Die Federungscharakteristik muss dabei weiter gefasst werden als nur auf die eigentlichen Federelemente des Drehgestells beschränkt. Auch die Steifigkeiten des Wagenkastens und weitere Steifigkeiten innerhalb der Drehgestelle können eine Rolle spielen. Bezüglich des Drehgestellrahmens wird dabei einem Aspekt bislang wenig Aufmerksamkeit geschenkt – der Bewertung und Optimierung seiner Steifigkeiten und Gestaltung im Hinblick auf die lauftechnischen Eigenschaften des Fahrzeugs. Inhalt der Arbeit ist die Auseinander-setzung mit dieser Thematik. Den Untersuchungen liegt die repräsentative Ausführungsform eines Drehgestellrahmens in Doppel-H-Form mit 2 Langträgern und 2 Querträgern zu Grunde. Mit Hilfe eines Stabmodells, welches diese Rahmenform nachbildet, werden Berechnungsformeln für die maßgeblichen Steifigkeiten des Drehgestellrahmens aufgestellt. Durch Parametervariationen am Rechenmodell wird gezeigt, wie sich die Steifigkeitseigenschaften des Drehgestellrahmens durch andere Geometrien, Trägerquerschnitte oder Werkstoffe verändern. Es zeigt sich, dass die Rahmensteifigkeiten selbst in verhältnismäßig großen Wertebereichen variieren können. Da für die lauftechnische Bewertung die Steifigkeiten des Drehgestellrahmens nicht isoliert zu betrachten sind, sondern in Reihenschaltung zu den verhältnismäßig geringen Primärfedersteifigkeiten, relativiert sich diese Aussage. An Hand statischer und dynamischer lauftechnischer Kenngrößen werden die Auswirkungen der Rahmensteifigkeiten auf das lauftechnische Verhalten des Schienenfahrzeugs untersucht. Dafür werden vereinfachende Rechenmodelle aufgestellt bzw. ein existierendes Mehrkörper-Simulationsprogramm genutzt, womit die gesuchten Werteverläufe bestimmt werden. Die Wirkung der Drehgestellrahmensteifigkeiten kann danach in unerwünschte, parasitäre Steifigkeiten und erwünschte Steifigkeiten unterschieden werden. Zu den parasitären Steifigkeiten des Drehgestellrahmens zählen die Biegesteifigkeiten vertikal und quer sowie die Schersteifigkeit. Hier sind bei der Auslegung ausreichend hohe Werte anzustreben. Andernfalls verschlechtern sich Kennziffern wie der Neigungskoeffizient, die kri-tische Geschwindigkeit und das Vertikalschwingverhalten der primär abgefederten Masse. Die Verwindungssteifigkeit des Rahmens wirkt als erwünschte Steifigkeit positiv auf das lauftechnische Verhalten. Mit kleinen Werten kann die Sicherheit gegen Entgleisen in Gleisver-windungen signifikant verbessert werden. Die gegensinnige Längssteifigkeit des Rahmens würde bei sehr niedrigen Werten den erwünschten Effekt haben, die Führungskräfte im Bogen zu reduzieren. Gleichzeitig ginge dies aber zu Lasten der kritischen Geschwindigkeit, da diese Steifigkeit dort als parasitäre Steifigkeit wirkt. Die Untersuchungen zeigen allerdings, dass die für diese beiden Effekte erforderlichen kleinen Wertebereiche mit dem ausgewählten Rahmentyp nicht erreicht werden. Weiterhin wird der Einfluss der Drehgestellrahmenmasse untersucht. Durch Werkstoffauswahl und Bauweise können hier Veränderungen erzielt werden. Eine niedrige Rahmenmasse begünstigt das vertikale Schwingungsverhalten und verbessert zusammen mit niedrigen Massenträgheitsmomenten die kritische Geschwindigkeit. Kleine Werte bei den erwünschten Steifigkeiten und hohe Werte bei den parasitären Steifigkeiten bei gleichzeitig niedriger Masse sind in der konventionellen Rahmenbauweise schwer vereinbar. Aus diesem Grund wird abschließend ein masse- und steifigkeitsoptimierter Dreh-gestellrahmen vorgeschlagen, der diesen Auslegungskonflikt auflösen kann. Die überschläglich kalkulierten Werte für die Steifigkeiten und die Rahmenmasse bestätigen die Vorteile des Konzepts. Die durchgeführten Untersuchungen belegen, dass es sinnvoll und zweckmäßig ist, die Steifigkeitsparameter des Drehgestellrahmens bereits in der Entwurfsphase des Fahrzeugs zu analysieren und ggf. einer Optimierung zu unterziehen. Mit den vorgestellten Berechnungs-werkzeugen wird eine geeignete und zeitsparende Möglichkeit dafür aufgezeigt.

Light Rail Transit (LRT) has been getting more attention in U.S. cities due to its socio-economic benefits, such as reducing pollution and congestion, as well as promoting regional economic development. However, huge capital costs remain an obstacle to the construction of a new light rail system. For this reason, cities in the planning phases of LRT want to use value capture tools to finance transit construction and operation. In theory, any improvement in a transportation structure that increases accessibility and reduces transportation cost can be capitalized into property values in an area. In turn, governments levy taxes on a portion of the additional value of adjacent properties. This study, however, aims to empirically examine whether value capture is possible in the recession when property and land values continue to decrease. The study uses the case of the DART Green Line, which started to run in 2009 just after a financial crisis in the U.S. The 5745 residential parcels are analyzed with using a hedonic price model in order to detect the Green Line’s influence on residential values before and after the recession. To enhance the proficiency of the regression, this study includes several structure and neighborhood characteristics. The statistical results found the Green Line’s benefits on residential values both in the pre-Green Line period (before the recession) and the post-Green Line period (during the recession). It is noteworthy there are still positive influences of transit accessibility on residential values even in the unstable housing market, although the magnitude of the variable has diminished compared to the pre-Green Line period. / text

Light rail transit (LRT) systems are tools to help reduce traffic congestion and air pollution, promote high-density development and more affordable housing, and curtail urban sprawl in metropolitan cities throughout the United States. The impact of transit system services on property values has been studied from various perspectives using many statistical approaches. There are two general categories of effects that proximity to a light rail system can have on the value of residential properties: accessibility benefits (experienced in close proximity to the LRT stations) might increase property values, while nuisance qualities (experienced in both proximity to the LRT line and stations) could have a negative effect on residential property values. Due to the opposing nature of these coexisting effects, results from many empirical studies have been contradictory or inconclusive. This report reviews the spectrum of results found by the growing body of literature focusing on the capitalization effects of rail stations on property values. The economic effect of one particular LRT system, the 7.5 mile long METRORail line located in Houston, Texas, on the value of properties within close proximity to rail stations has not been thoroughly examined, as it only opened for service in 2004. This study utilizes property data acquired from the Harris County Appraisal District (HCAD), Geographic Information System (GIS) techniques, and Hedonic Price Models to analyze the impact of the LRT system in the city of Houston, Texas, on the value of residential properties that lie within close proximity to the line’s rail stations. / text

It is of nearly universal acceptance that one of the pillars of American economic success over the course of the 20th century was the rapid development of infrastructure. Transportation infrastructure has been of particular importance in the rise of the United States and attributed to the spread of an increasingly mobile culture. Americans undoubtedly enjoy traveling, and the ability to do so with relative ease is of immense value to many. In Texas, the majority of economic activity takes place within what is colloquially known as the “Texas Triangle”, an area bounded by the large metropolitan areas of Houston, Dallas-Ft. Worth, and San Antonio. Intensive population growth in Texas, anchored by the triangle, has led to increasing road congestion on many routes, especially along Interstates 35 and 10. This congestion, and the wasted time and money that comes with it, are of increasing concern to the future economic vitality of the state. The Texas Triangle is also served by extensive aviation links via major airports in the major metropolitan areas, as well as smaller airports in other parts of the region. These flights, operated by American Airlines, Continental Airlines, and Southwest Airlines are frequent, but emit large amounts of greenhouse gases that contribute to ground level pollution and possibly climate change. High-speed rail has been considered by many to be a superior environmental option for intercity routes with lengths inherent to the Texas Triangle. However, given the fact that Texas is the top emitter of carbon dioxide in the U.S. and relies on an energy mix that is primarily fossil fuel powered; would a potential high-speed rail in Texas outperform the current air system environmentally, given similar passenger miles traveled? This report examines the environmental emissions of high-speed rail and compares it to the environmental emissions of our current aviation system, taking into account a life-cycle perspective. / text

This thesis examines the characteristics of railway infrastructure development and associated issues in Manitoba, Canada. The period under consideration dates from when the first tracks were laid in 1878 through to the completion of the Hudson Bay Railway in 1929. Setting the scene is a template for railway development in general, one that allows hypotheses to be drawn that are specific to Manitoba. In order to test those hypotheses it is necessary to first provide a comprehensive overview of the historical evolution of the railway network. Next, aspects of graph theory are reviewed, identifying the methodology most appropriate for a spatial analysis of railway networks. This analysis attempts to draw conclusions about the relationship between the railway companies and the governments, people and geography that they were compelled to deal with. The testing of these forms revealed that while the Manitoba railway network is very complex, it never arrived at the maximum possible complexity.