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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Aerodynamic Improvements for Auto-Carrying Railcars

Condie, Robert Arthur 29 May 2014 (has links)
The railroad industry is responsible for the mass transport of a vast numbers of goods throughout the United States. As needs and capabilities of the railroad industry have changed, the interest in reducing the resistance of locomotives and railcars has increased. This has become paramount as fuel prices have increased in recent years. Resistant forces can result from friction in mechanical components and aerodynamic drag of the moving train. As the average traveling speeds of trains have increased, aerodynamics are contributing a larger fraction of the overall resistance. For this reason, the aerodynamic profiles of trains have become a topic of research. Furthermore, current manufacturing practices of railcars provide an opportunity for research in modifications that reduce the aerodynamic drag. This thesis reports on research that has been done to reduce aerodynamic drag on automobile-carrying railcars. Data was collected by placing G-scale (1/29) models into a wind tunnel with a 0.74 m^2 test section. These models were tested for Reynolds Numbers ranging from approximately 2.05 x 10^5 to 2.79 x 10^5. Modifications were made to the models with the intention of reducing the drag. The profile features of the auto-carrying railcars were reviewed and three regions were chosen to be the focus of this study. The selected regions are the roof, side panels and structural chassis region. Special attention was given to the regulations of the railroad industry to ensure the tested modifications would be candidates for implementation. From the data, it was determined that drag could be reduced by modifying or covering the roof, side panels and chassis structure by nominally 20%, 5% and 15% respectively.
22

DERAILMENT RISK ASSESSMENT

Wagner, Simon John, simonjwagner@gmail.com January 2004 (has links)
There is a large quantity of literature available on longitudinal train dynamics and risk assessment but nothing that combines these two topics. This thesis is focused at assessing derailment risks developed due to longitudinal train dynamics. A key focus of this thesis is to identify strategies that can be field implemented to correctly manage these risks. This thesis quantifies derailment risk and allows a datum for comparison. A derailment risk assessment on longitudinal train dynamics was studied for a 107 vehicle train consist travelling along the Monto and North Coast Lines in Queensland, Australia. The train consisted of 103 wagons and 4 locomotives with locomotives positioned in groups of two in lead and mid train positions. The wagons were empty hopper wagons on a track gauge of 1067mm. The scenarios studied include: the effect of longitudinal impacts on wagon dynamics in transition curves; and the effects of longitudinal steady forces on wagon dynamics on curves. Simulation software packages VAMPIRE and CRE-LTS were used. The effects of longitudinal impacts from in-train forces on wagon dynamics in curves were studied using longitudinal train simulation and detailed wagon dynamics simulation. In-train force impacts were produced using a train control action. The resulting worst-case in-train forces resulting from these simulations were applied to the coupler pin of the wagon dynamics simulation model. The wagon model was used to study the effect of these in-train forces when applied in curves and transitions at an angle to the wagon longitudinal axis. The effects of different levels of coupler impact forces resulting from different levels of coupling slack were also studied. Maximum values for wheel unloading and L/V ratio for various curve radii and coupler slack conditions were identified. The results demonstrated that the derailment criteria for wheel unloading could be exceeded for a coupler slack of 50mm and 75mm on sharper curves, up to 400m radii. A detailed study of the effect of steady in-train forces on wagon dynamics on curves also was completed. Steady in-train forces were applied to a three wagon model using VAMPIRE. Maximum and minimum values of wheel unloading and L/V ratio were identified to demonstrate the level of vehicle stability for each scenario. The results allowed the worse cases of wheel unloading and L/V ratio to be studied in detail. Probability density functions were constructed for the occurrence of longitudinal forces and coupler angles for the Monto and North Coast Lines. Data was simulated for a coupler slack of 25, 50 and 75mm and force characteristics were further classified into the occurrences of impact and non-impact forces. These probability density functions were analysed for each track section to investigate the effects of coupler slack, track topography and gradient on wagon dynamics. The possible wagon instability in each of these scenarios was then assessed to give a measure of the potential consequences of the event. Risk assessment techniques were used to categorise levels of risk based on the consequences and likelihood of each event. It was found that for the train configuration simulated, the Monto Line has a higher derailment risk than the North Coast Line for many of the scenarios studies in this thesis. For a coupler slack of 25mm no derailment risks were identified, 50mm coupler slack derailment risks were only identified on the Monto track and the majority of derailment risks were identified for a 75mm coupler slack.
23

An Experimental study on identification of planetary gear train system by Using Genetic Algorithms

Liu, Kun-Nan 04 July 2001 (has links)
Abstract In this thesis, a simple dynamic model of the planetary gear train system is developed. Because of the dynamic equations deriving from designing a planetary gear train system are complex and nonlinear, and the controller design is difficult. If we take the planetary gear train system as a pure speed-down mechanism, and then the accuracy of the planetary gear train system will lose. So, we develop the dynamic equations of the planetary gear train system concerning with the conception of friction losses. Furthermore, the MGA method is used to identify the parameters of this system. The modified genetic algorithm (MGA) is proposed from the simple genetic algorithm (SGA) with some additional strategies, such as Elitist and Extinction strategies. From the computer simulations and the experimented results, it is concluded that the parameters of this system searched by using MGA will be more precise than the parameters searched by using LMS.
24

Railway and grade : the historical construction of contemporary identities

Strangleman, Tim January 1998 (has links)
This thesis attempts to understand the role and meaning of occupational identity in the contemporary British railway industry. It examines the way in which culture change initiatives and programmes have explicitly targeted an older 'railroad culture'. The study explores the way such a culture was portrayed by successive Conservative Governments and management as being a major obstacle to change, and a historic reason why the industry has under performed. The notion of the past failure of the industry, and a cultural analysis predicated on such assumptions, is challenged. Employing a historical and comparative research strategy, it is argued here that grade and industry culture is an emergent autonomous property of the workforce itself and as such attempts to change it are misguided, and at times positively harmful to the organisation. The research uses a variety of material collected from London Underground and former British Rail companies, including documentary sources, semi-structured interviews and non-participant observation techniques.
25

March 11, 2004 attack on the Madrid commuter rail system

Levings, Robert S. Kelsay, John, January 2006 (has links)
Thesis (M.A.)--Florida State University, 2006. / Advisor: John Kelsay, Florida State University, College of Social Sciences, Dept. of International Affairs. Title and description from dissertation home page (viewed June 6, 2006). Document formatted into pages; contains iv, 41 pages. Includes bibliographical references.
26

Integrated optimization and simulation models for the locomotive refueling system configuration problem

Verschelden, Lucas George January 1900 (has links)
Master of Science / Department of Industrial and Manufacturing Systems Engineering / Todd W. Easton / Jessica L. Heier Stamm / Locomotives in the U.S. use over 3 billion gallons of fuel each year and faster refueling can increase rail network capacity without the infrastructure cost associated with new terminals or tracks. This thesis introduces the locomotive refueling system configuration problem (LRSCP), which seeks to improve efficiency in refueling yards through new technologies or policies. This research also creates two new methods to solve LRSCP. The first method uses an integer program to solve the off-line LRSCP and develop a static refueling policy. The train refueling integer program, TRIP, maximizes the weighted number of train combinations that can be refueled without delay. TRIP is optimized and its outputs are used as inputs to a simulation developed in Simio® for testing and validation. The second method creates an integrated integer program and simulation to solve the on-line LRSCP and produces a dynamic refueling policy. This tool, built in Python, incorporates a different integer program, the strike line integer program (SLIP), into the simulation. SLIP determines the optimal refueling assignment for each incoming train. The simulation incorporates SLIP’s solution for testing and validation. This tool is truly integrated and requires approximately 300 instances of SLIP to simulate a single day. Based on experimental results, solving either TRIP or SLIP and incorporating the optimal refueling policy improves railyard operations by 10 to 30%. This impact is statistically significant and increases the capacity of a railyard. Additionally, it impacts other important parameters such as time spent in the yard and the maximum queue for the railyard. Furthermore, there is a significant decrease in wasted time and an improvement to railyard efficiency. Implementing either method should increase a railyard’s capacity and significantly increase revenue opportunities.
27

On Motion Mechanisms of Freight Train Suspension Systems

O'Connor, Dennis 01 August 2014 (has links) (PDF)
In this dissertation, a freight train suspension system is presented for all possible types of motion. The suspension system experiences impacts and friction between wedges and bolster. The impacts cause the chatter motions between wedges and bolster, and the friction will cause the stick and non-stick motions between wedges and bolster. Due to the wedge effect, the suspension system may become stuck and not move, which cause the suspension lose functions. To discuss such phenomena in the freight train suspension systems, the theory of discontinuous dynamical systems is used, and the motion mechanism of impacting chatter with stick and stuck is discussed. The analytical conditions for the onset and vanishing of stick motions between the wedges and bolster are presented, and the condition for maintaining stick motion was achieved as well. The analytical conditions for stuck motion are developed to determine the onset and vanishing conditions for stuck motion. Analytical prediction of periodic motions relative to impacting chatter with stick and stuck motions in train suspension is performed through the mapping dynamics. The corresponding analyses of local stability and bifurcation are carried out, and the grazing and stick conditions are used to determine periodic motions. Numerical simulations are to illustrate periodic motions of stick and stuck motions. Finally, from field testing data, the effects of wedge angle on the motions of the suspension is presented to find a more desirable suspension response for design.
28

AN EXPERIMENTAL STUDY OF INCOMPRESSIBLE TURBULENT FLOW IN PIPES CONTAINING SPHERE TRAINS

Tawo, Edom 11 1900 (has links)
<p> The pressure gradients for sphere trains in 1 in. and 2 in. pipes have been measured with water flowing past the stationary spheres at Reynolds numbers (based on pipe diameter) from to 4 - 105 , and sphere/pipe diameter ratios ranging from 0.486 - 0.84. Two dimensionless pressure ratios have been derived so that the experimental results obtained can be generalised to any pipe diameter with the above constraints on Reynolds number and diameter ratio. Drag coefficients have also been calculated from pressure drop measurements for the 0.84 diam. ratio spheres in· 1 in. pipe. These have been compared with McNoun's drag coefficient. </p> <p> The application of the results to predict pressure gradients for sphere trains in any pipe diameter has been illustrated. </p> / Thesis / Master of Engineering (MEngr)
29

Searching for Constructed Form: A Station for Projective Geometry

Eskeland II, John T. 30 June 2015 (has links)
The project is dreamed as a monumental edifice standing beside the rail corridor of South-Western Virginia. Two pairs of towers rise from the earth transitioning from squares to ellipses. The towers are cut mid-ascent to shape an eastern face, orienting the project and the rail traffic beneath. / Master of Architecture
30

Investigation of Community Annoyance as Invoked by a High School Stadium and a Train Horn Proximal to Residentially Zoned Homes

Baker, Aubrey Anne 17 July 2015 (has links)
The effects of two different noise sources upon their surrounding communities were investigated with both quantitative and qualitative measures. A high school football game, which presents continuous noise over a relatively short duration on a predictable schedule was found to have a slight annoyance on its surrounding community. In contrast, a train horn blow at a residential intersection was investigated. This sound was unpredictable and could occur at any time. Residents in this community were found to have a moderate level of annoyance. It was found that each of the noises studied violated suggested noise levels for common household activities, in addition to many local, state, and federal noise regulations. It is recommended that both of the sounds studied herein be reduced or eliminated altogether. Limiting the level of sound produced by the PA system at the football game and using a noise reducing barrier would help in the case of the football game. Converting the railroad intersection into one with sufficient safety features, especially a crossing quad-gate that no longer requires trains to blow their horns would be the optimal solution, with the added benefit of precluding vehicles from entering the crossing when a train is present. / Master of Science

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