Thesis (M.Arch.)--University of Hong Kong, 1996. / Includes bibliographical references. Also available in print.

Thesis (M.Arch.)--University of Hong Kong, 2001. / Includes bibliographical references. Also available in print.

No description available.

Presently there are extremely high expectations on the railway in Sweden. As a result of the political will to strengthen the railways position in the transport market, a number of major railway projects have therefore been decided. However, the political ambition has also resulted in a greater need of capacity than before. Which has led to an overload of the Swedish railway network and therefore also wear of tracks, locomotives and wagons.Since the railway in comparison with for instance the car not always has been the most popular mode of transportation, then only a small part of the investment has been devoted to developing its system. This has resulted in matters and tasks within the area being greatly put aside. An example of a issue that has not been prioritized concerns guidelines for the shaping and usage of the walking ways on railway yards. At present, there are no guidelines for how these walking ways should look and be used, which has resulted in a number of injuries and accidents occurring among the workers.The purpose of this work is therefore to present new suggestions for the design and use of these walking ways. The goal has been to develop an overall assessment of the situation based on a visit to the railway yard in Hagalund, interviews with experts and an information gathering within the topic. This is intended to form the basis for the suggestions and in the future also for a safer environment for the workers.During the site visit to the depot in Hagalund, it was discovered that some of the walking ways in the yard were in need of maintenance. It turned out that they were not being filled up, because the stone fractions are considered to contaminate the macadam laying next to it. During the site visit, one saw how some of the streets disappeared among larger fractions and that there was macadam Class I on the yard, although it is not allowed to be there. With the help of the interviews, one could map out the reason why it looks like it does today at the depot in Hagalund. In the discussions with the various characters, there was clearly a need to renew and standardize the guidelines for how these walking ways should be built and maintained. With the help of the site visit and the interviews, our proposals for guidelines were developed. One proposal is at least a width of 0.7 m along streets intended for walking along existing tracks and 0.7-1 m along future ones.

The understanding of rail vehicle steady-state and dynamic curving has increased substantially in the last few years. Contemporary curving models include such nonlinear effects as two-point contact, creep force saturation, and rail flexibility. The usual approximation concerning the contact geometry is that the Iocalized wheel and rail curvatures at the center of the contact patch are constant throughout the contact patch. This approximation allows computation of contact stresses using Hertzian theory, and it allows the computation of contact patch forces using one of Kalker’s theories. In vehicle curving, contact usually occurs at or near the wheel flange, where the wheel/rail contact geometry is non·Hertzian. Furthermore, after being in service for some time, the wheel and rail profiles provide non·Hertzian geometry due to wear. Both of these effects tend to invalidate the assumption of Hertzian contact geometry in the contact region. This work uses a generic wheelset model which is the basic component of any rail vehicle model. The wheel/rail interaction is modelled using the finite element method. The wheel is generated as a surface of revolution of its tread profile, and the rail is generated as an extrusion of the rail head profile. Three—dimensional contact elements are used to characterize the wheel/rail interface. A simple stick/slip friction model is used wherein relative motion is permitted if the tangential force exceeds the adhesion limit, and no relative motion occurs otherwise. The results show that the finite element method was successfully used to solve the static contact problem. Both Hertzian and non-Hertzian contact problems were anaIyzed correctly. However, the application of the finite element method to the rolling contact problem was not completely successful. The finite element method results for tangential contact forces were about 25 percent lower than forces predicted by Kalker’s theory. Recommendations for extending the analysis to solve the rolling contact problem are made. The report includes a derivation of the wheelset steadystate equations of motion, as well as a solution algorithm for the nonlinear, algebraic equations. / Master of Science / incomplete_metadata

The main goal of this research is to develop new and innovative designs for insulated rail joints for improved life cycle and higher cost effectiveness. The research focuses on using electrically insulating materials that replace the epoxy used in current bonded insulated joints. Insulated joints (commonly known as "IJ") are widely used on railways to electrically insulate rail segments from each other, while mechanically connecting them together. The electrical insulation is necessary for accommodating track signals. The mechanical strength is needed to ensure the rail and IJs are able to withstand the vertical, longitudinal, and lateral forces that commonly occur on track. Insulating materials that can replace the epoxy used in bonded insulated joints are researched. The electrical insulation properties and mechanical strength of different materials are examined to determine the suitability of different materials for use in insulated joint. The most promising materials for use are determined to be fiber reinforced polymers and ceramics. Insulated joint designs are developed to accentuate the strengths of these two materials. The Insulating Metal Composite (IMC) insulated joint design that uses ceramics is determined to be the most promising of the new designs and is pursued through prototype fabrication. This particular joint design is analyzed structurally using both closed form analysis and FEA analysis using the software package ABAQUS. Electrical analysis using PSPICE is carried out on the joint. Prototypes of several design iterations of the insulating metal composites are built and tested. A proof of concept static bending test of the insulating metal composites used to build the IMC insulated joint is performed using a Tinius Olsen compressive tester. A rolling-wheel load test is performed on a prototype IMC component installed in rail. Finally, a prototype of a complete IMC insulated joint is fabricated and installed on the FAST test track at TTCI facility in Pueblo, Colorado for field evaluation. Electrical testing using a megohmmeter is performed on a complete prototype joint. Structural analysis shows that the components used to construct the IMC insulated joint can withstand the vertical and longitudinal loads applied to them. Electrical analysis shows that the joint can provide adequate electrical insulation and provides the required dielectric strength in the AREMA Manual for Railway Engineering. The proof of concept test shows that an IMC component can withstand 100 kips of static load without damage. The rolling-wheel load test shows that the ceramic in the IMC components can withstand a large shock load and that the rail used in the IMC insulated joints can survive repeated and shock loads. The testing of the prototype joint on the FAST track, which is ongoing at this time has shown that the new joint concept is fully capable of providing adequate electrical insulation and mechanical strength throughout the expected life of IJs. / Master of Science

Ph. D.

For over a decade proposals for connecting the metropolitan areas of Austin and San Antonio, Texas via passenger rail have been studied. In the Texas Department of Transportation’s 2010 Rail Plan several ideas, including high-speed rail, regional Amtrak service, and a new passenger rail service have been proposed as a means to provide an alternate mode of transportation along the I-35 corridor. Union Pacific Railroad currently owns and operations a rail line that connects the Austin and San Antonio metropolitan areas; each of the passenger rail projects proposes sharing this corridor with Union Pacific. A literature review reveals that a key factor in negotiating with a freight railroad for shared use of a corridor is safety. One element of the safety risk analysis is the evaluation of at-grade highway-railroad crossing. This study discusses the Austin-San Antonio corridor, its current mobility challenges and the proposed passenger rail projects. It then discusses rail safety as expressed in the literature and provides background about safety at highway-railroad crossings. Crossing inventory and accident data, as maintained by the Federal Railroad Administration (FRA), is then analyzed using regression modeling in an attempt to better understand the relationship between the physical and operational characteristics of highway-railroad crossings and accidents on corridors shared by freight and passenger rail. It analyzes a five-year accident history (2005 to 2009) from of a sample of shared use highway-rail crossings throughout the US. The findings are then used to analyze the at-grade highway-railroad crossings along the Austin-San Antonio corridor. And finally, the implications of the findings are discussed. The findings of this report recommend that characteristics of the built environment such as land use, number of traffic lanes, and function classification of the roadway should be considered when assessing accident risk at highway-railroad crossings. In addition, this analysis reveals the need for a way to better measure safety risks at private highway-railroad crossings. / text

Doctor of Philosophy / Department of Civil Engineering / Robert J. Peterman / This dissertation describes a testing program to evaluate the bond and splitting propensity characteristics of 5.32-mm-diameter prestressing wires. Prestressing wire reinforcement is used primarily in the production of prestressed concrete railroad ties. Twelve different 5.32-mm-diameter wires were tested in this study in order to measure bonding characteristics of the reinforcement. Establishment of the bond-slip characteristics of these reinforcement at both transfer of prestress (transfer bond) and under flexural loading (flexural bond) is necessary to enable the accurate modeling of these ties using finite elements. Transfer bond and flexure bond of various indent patterns were tested using tensioned pullouts. Specimens of various sizes with single or multiple wires were tested to determine the effects of cover and wire number on bond. Indents were machined on smooth prestressing wires to accurately compare indent geometries. Lateral expansion was tested to determine which wires have higher propensity to cause cracking or splitting. Crossties were instrumented to compare resulting lateral expansion with results found in the laboratory. The results from the testing program showed that the tensioned pullout test was able to be used to predict the transfer length of prisms made with the same reinforcement. The results also showed that the indent geometries were able to be used to predict the splitting of specimens based on the amount of slip the wire had experienced. The testing also showed the importance of concrete cover with the relation to splitting potential.

Master of Science / Department of Civil Engineering / Robert J. Peterman / This thesis presents results from transfer length measurements on prestressed concrete railroad ties. Results are shown from the four main producers of concrete ties in the United States. Six prestressed concrete tie plants were visited by the research team to measure transfer length on ties with various mix designs and prestressing reinforcement. After all plants had been visited, a total of nine concrete-mix designs and 10 reinforcement variations were tested. Overall, 220 transfer length measurements were conducted on prestressed concrete railroad ties during the duration of this research project. This was the first coordinated effort to measure transfer lengths in concrete railroad ties ever conducted in the industry. Concrete strains were monitored using the standard Whittemore gage, as well as a non-contact procedure called laser-speckle imaging (LSI). This method to measure transfer lengths has been developed at Kansas State University (KSU). Ties measured using the Whittemore gage were sent back to the civil engineering structural laboratory at KSU so the long-term transfer lengths could be monitored. After a certain period of time, the ties were load-tested according to the American Railway Engineering and Maintenance-of-Way Association (AREMA) loading specifications of the rail-seat positive moment test.