This thesis contains a design for two axle railcar suspension. Functionality of the design was verified using analytical and numerical calculations.

This study evaluates the dynamic interaction between rail vehicles and the track on which they travel. The measurements were analyzed in the time and frequency domain. The effects of external parameters such as the vehicle design, subgrade stiffness, and degree of curvature were analyzed and compared for both the vehicle response and the track geometry data. This study was conducted in close cooperation with the Transportation Technology Center, Inc. (TTCI) in Pueblo, Colorado. The track and vehicle response data was collected on the High Tonnage Loop at TTCI over a span of approximately ten years. For the purpose of this study, TTCI provided this data to the Advanced Vehicle Dynamics Laboratories (AVDL) at Virginia Tech. The analysis of the data was first completed for the vehicle response and track geometry measurements separately. In this manner, the effects of the subgrade stiffness, the degree of curvature, and the vehicle design could be evaluated for each of the measurements. The analysis of the track and rail vehicle response was successfully completed, and the results from this analysis are presented in the following chapters. The analysis showed that the subgrade stiffness had a significant effect on the vertical wheel loads, the track crosslevel, and the track gauge. For an increase in the degree of curvature, the variation of the crosslevel increased. The dynamic response of the vertical and lateral wheel loads showed a significant dependence on the alignment of the rails. Improvements for future studies of the interaction between the track and rail vehicles have been recommended. / Master of Science

Rail vehicle dynamicists Frequently employ roller rigs to study the complex dynamic response of vehicles and trucks. This work presents the analytical and experimental investigation of a one-fifth scale model of a typical North American three-piece Freight truck running on a roller rig. The roller rig was built as part of this research For the Department of Mechanical Engineering at Virginia Polytechnic Institute and State University. Linear and nonlinear mathematical models were also developed to simulate the lateral dynamics of the truck running on the roller rig. The nonlinear model incorporates a lookup table For the wheel/rail geometric constraints, a heuristic creep force model to take into account creep force saturation, and it includes the effects of Coulomb friction in the truck bearings. The linear model predicts the truck's natural Frequency versus speed within 5% of the experimental values. lt also predicts the damping ratio decrease that occurs with increasing truck speed. The nonlinear model simulates the lateral instability known as hunting. The nonlinear model and the roller rig also exhibit small amplitude hunting, in which flange contact does not occur. The nonlinear model simulates the experimentally observed increase in oscillation Frequency that accompanies the onset of flange contact. / Master of Science

Structures and material combinations, tailored for multiple purposes, are within the reach of vehicle manufacturers. Besides reducing the environmental impact of the transportation sector these multi-functional structures can reduce costs, such as development, manufacturing and maintenance, and at the same time offer improved comfort to the passengers. This thesis sets out to develop multi-functional design algorithms and evaluate concepts for future composite high speed train car bodies with the objective of optimising the amount of mass needed to fulfil all functions of the structure. In a first step complete composite car bodies were developed, optimised and evaluated based on global stiffness requirements and load cases. The knowledge gained in this step was used as requirements for the strength and stiffness of panels during the continued development of the multi-functional optimisation which, besides strength and stiffness, later also considers sound transmission, thermal insulation, geometric restrictions, manufacturability and fire safety. To be able to include fire safety in the analysis, a method for simulating the high temperature response of layered composite structures was needed, and developed. Significant weight reductions are proven when utilising carbon fibre in the load carrying structure of the vehicle, on component level as high as 60%. Structures can be made significantly thinner when using the algorithms developed in this thesis and wall thickness is reduced by 5-6 cm. Analysis carried out and extensive literature surveys also suggest significant cost savings in manufacturing, maintenance and use-phase, even thou the raw material cost can be significantly higher as compared to the conventional steel or aluminium alternatives. Results from drive cycle simulations showed that the benefit, with respect to reduced energy consumption, is in the range of 0.5-0.8% per reduced weight percentage, comparable to both automotive and air applications. The algorithms and methods established in this thesis can be directly applied for the development and analysis of future high speed train car bodies. / <p>QC 20130521</p>

Ground-borne vibration from underground rail vehicles is studied analytically. A previously developed model by J.A.Forrest and H.E.M.Hunt is modified to account for different track and vehicle models. The tunnel is modeled as infinite cylindrical shell surrounded by viscoelastic soil. The track is coupled to the tunnel with supports of complex stiffness. The rails, which are modeled as infinite Euler beams, are supported by discrete sleepers with regular spacing, and railpads with complex stiffness. A modified hysteretic damping model for moving loads is applied to soil. Linearized Hertzian contact spring is included between the wheel and the rail. The solution is obtained in frequency domain using random process theory. Effects of improvements in the model are graphically presented to enable comparison with the previously developed model and measurements from literature.

Hunting is a very common instability exhibited by rail vehicles operating at high speeds. The hunting phenomenon is a self excited lateral oscillation that is produced by the forward speed of the vehicle and the wheel-rail interactive forces that result from the conicity of the wheel-rail contours and the friction-creep characteristics of the wheel-rail contact geometry. Hunting can lead to severe ride discomfort and eventual physical damage to wheels and rails. A comprehensive study of the lateral stability of a single wheelset, a single truck, and the complete rail vehicle has been performed. This study investigates bifurcation phenomenon and limit cycles in rail vehicle dynamics. Sensitivity of the critical hunting velocity to various primary and secondary stiffness and damping parameters has been examined. This research assumes the rail vehicle to be moving on a smooth, level, and tangential track, and all parts of the rail vehicle to be rigid. Sources of nonlinearities in the rail vehicle model are the nonlinear wheel-rail profile, the friction-creep characteristics of the wheel-rail contact geometry, and the nonlinear vehicle suspension characteristics. This work takes both single-point and two-point wheel-rail contact conditions into account. The results of the lateral stability study indicate that the critical velocity of the rail vehicle is most sensitive to the primary longitudinal stiffness. A method has been developed to eliminate hunting behavior in rail vehicles by increasing the critical velocity of hunting beyond the operational speed range. This method involves the semi-active control of the primary longitudinal stiffness using the wheelset yaw displacement. This approach is seen to considerably increase the critical hunting velocity. / Master of Science

This Diploma thesis is aimed at testing centre at the assembly line for boarding steps and ramps for rail vehicles. This project describes various activities and issues associated with the testing of these products. The project also evaluates current testing processes and proposes optimal future state and recommends solutions necessary to achieve this. A new design of a testing centre is also developed.

Before vehicles can be placed in service it has to complete an authorisation process. At the moment,this process is largely depended on tests. This is, however, an expensive and long process. With new technologies and improved simulations this process can be shortened and the costs can be lowered. The validation of a vehicle model, however, is often limited by the available data. Often the measured rail profiles are not available and thus a new UIC60 profile is used for the simulations. The railway track often has been used and showssigns of wear and damages, therefore research has been done to investigate the influence of the rail profiles on the validation of a railway vehicle model. The current methods of validation in the European norm are used to compare simulated values with forces and accelerations available from vehicle measurements. In the first step,25 track sections with different curve radii have beensimulated with a measured rail profile every 100 meters. In the next step, the same sections have been simulated by using the standard UIC60 rail profile. The results show that the use of measured rail profiles does have a positive influence on the outcome of simulation. In the final step, one single narrow curve has been simulated to show the effect of standard and worn rail profiles. Four different wear stages of the rail profile are simulated and compared to the available vehicle measurements available. These simulations show that the use of a medium worn rail profile gives the most accurate value. / Innan ett fordon kan tas i bruk måste det genomgå en tillståndsprocess. För närvarande är denna process till stor del beroende av provningar. Detta är dock en dyr och lång process. Med hjälp av ny teknik och förbättrade simuleringar kan denna process förkortas och kostnaderna sänkas. Valideringen av en fordonsmodell begränsas dock ofta av de tillgängliga uppgifterna. Ofta finns inte de uppmätta rälsprofilerna tillgängliga och därför används en ny UIC60-profil för simuleringarna. Järnvägsspåret har ofta använts och visarDärför har forskning gjorts för att undersöka hur rälsprofilerna påverkar valideringen av en modell av ett järnvägsfordon. De nuvarande valideringsmetoderna i den europeiska normen används för att jämföra simulerade värden med de krafter och accelerationer som finns tillgängliga från fordonsmätningar. I det första steget har 25 spårsektioner med olika kurvradier använts.simulerats med en uppmätt rälsprofil var 100:e meter. I nästa steg har samma sektioner simulerats med hjälp av standardprofilen UIC60. Resultaten visar att användningen av uppmätta rälsprofiler har en positiv inverkan på simuleringsresultatet. I det sista steget har en enda smal kurva simulerats för att visa effekten av standard- och slitna rälsprofiler. Fyra olika slitningsstadier av rälsprofilen simuleras och jämförs med tillgängliga fordonsmätningar. Simuleringarna visar att användningen av en mediumsliten rälsprofil ger det mest exakta värdet.

Made available in DSpace on 2015-05-08T14:59:51Z (GMT). No. of bitstreams: 1 parte1.pdf: 2517556 bytes, checksum: 9883a09fdf1ae27baf9f5980a3611a85 (MD5) Previous issue date: 2009-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This paper presents the development of a dynamic telemetric system of rail transit vehicles in metropolitan rail meshes that uses the transmission of signals via radio, according to communication protocol international standard. It consists of microcontrollers and of a radio transceiver, which, when coupled to sensors, capture and transmit the data in question, acting as a wireless transducer. It is modular technology of low cost, low power, consumption security and it is also capable of monitoring several variables simultaneously. It is innovative with regard to the monitoring of vehicles operating in permanent ways, assessing real-time performance. This assessment is intended to assist in preventive and corrective operation and maintenance of rail vehicles in order to improve the quality of services provided. This system has as main objective to enable a constant evaluation of factors which influence in the performance of the trains, as actual speed and pressure on the stock air suspension, so as to allow intervention strategies, thus avoiding a partial or total degradation of the transport services to passengers. To perform real-time telemetry, a network of wireless sensors, using ZigBee technology was set up in the way of traffic. The network made the capture and transmission of data collected from a train to the base station where a program installed on a personal computer is instructed to receive and send the collected data through an Ethernet network to a central monitoring system. The base station system acts as a data server providing information to a monitoring system installed in the Operational Control Center (OCC) of the Brazilian Company of Urban Train - Recife (CBTU / METROREC). The monitoring system installed in OCC is responsible for managing the storage and display of data received. It will display data and graphics in real time allowing traffic controllers monitor the functioning of the train and detect possible problems. The system also stores the data in a database for further studies. / Este trabalho apresenta o desenvolvimento de um sistema telemétrico dinâmico de veículos em malhas metroferroviárias que utiliza a transmissão de sinais via radiofrequência, de acordo com protocolo de comunicação padrão internacional. Compõese de microcontroladores e um rádio transceptor, que, quando acoplados a sensores, captam e transmitem os dados em questão, funcionando como transdutores sem fio. Tratase de tecnologia modular de baixo custo, baixo consumo de energia, segura e capaz de monitorar diversas variáveis simultaneamente. É uma técnica inovadora no que se refere ao monitoramento de veículos que circulam em vias permanentes, avaliando em tempo real o seu desempenho. Essa avaliação pretende-se que auxilie nas ações preventivas e corretivas de operação e manutenção dos veículos rodoferroviários, a fim de melhorar a qualidade dos serviços prestados. Esse sistema tem como principal objetivo permitir uma constante avaliação de fatores que influenciam o desempenho dos trens, como velocidade real e pressão nas bolsas de ar da suspensão, de forma a possibilitar estratégias de intervenção, evitando assim uma degradação parcial ou total dos serviços de transporte prestados aos passageiros. Para realizar a telemetria em tempo real, montou-se na via de tráfego uma rede de sensores sem fio, com tecnologia ZigBee. Essa rede efetuou a captação e envio dos dados coletados em um trem até a estação base onde um programa instalado em um computador pessoal fica encarregado de receber e enviar os dados obtidos, por meio de uma rede ethernet, a um sistema central de supervisão. O sistema da estação base atua como um servidor de dados disponibilizando informações para um sistema de supervisão instalado no Centro de Controle de Operacional (CCO) da Companhia Brasileira de Trens Urbanos Metrô do Recife (CBTU/METROREC). O sistema de supervisão instalado no CCO é responsável por gerenciar o armazenamento e a visualização dos dados recebidos. Ele exibirá os dados e gráficos em tempo real permitindo aos controladores de tráfego analisar o funcionamento do trem e detectar possíveis problemas. O sistema também armazenará os dados em um banco de dados para a realização de estudos posteriores.

This work deals with construction of an experimental measuring stand. This stand will be used for research focused on wheel flange lubrication improvement. The construction is based on wheel flange lubrication system Tribotec OK-02. First part treats of rail vehicle dynamics and wheel flange lubrication problematics, second part describes construction itself.