Academic literature on the topic 'HIGH SPEED TRACK'

In the last 40 years an increase in train speed and axle load around the world and other challenges in the conventional ballasted track system gave birth to ballastless railway track system. This study examines in depth the various slab track systems that are being used today. Their design characteristics as well as the various requirements for efficient use are thoroughly explained. At least 34 different ballastless systems have been recorded in many railway networks throughout the world. The most significant slab track systems are analysed in detail and compared. Slab track designs have significant advantages comparing to ballasted tracks. The most significant are the high stability of the track, the almost non-existent need for maintenance, the long life cycle (60 years) and the reduced weight and height of the track. Their disadvantages against the ballasted tracks are mainly summarized in their higher construction costs. The Finite Element package ABAQUS/CAE is used to model a 3-D slab track design under static traffic loading. The results suggest that slab tracks have profoundly better stability and durability comparing to ballasted tracks mainly due to their higher stiffness and strength. The author underlines the need for further studies to undoubtedly prove the claimed advantages of slab track systems as well as to improve the costs associated with construction.

High-Speed Rail (HSR) as a fast, reliable and environmentally friendly mode of transportation has received a lot of attention in recent decades. The International Union of Railways reported that there are more than 18600 miles of HSR in operation and about 1.6 billion passengers per year are carried by them. Although there are plans for HSR in many states including Florida, the United States, however, is still hesitant to develop its own HSR network. One of the main barriers to developing high-speed rail is excessive vibration propagation to the media which may cause annoyance to people who live in the track neighborhood. Train induced vibration also contributes to track settlement, developing track flaws, and increasing life cycle cost of track and supporting structures. The aim of this research is to address this problem by conducting a comprehensive investigation into track dynamics. For this purpose, three-dimensional mass-spring-damper models of vehicle, track and supporting structures were developed and matrices of mass, stiffness, and damping of each subsystem were formed. The response of the whole system was, then, determined by coupling the subsystems using Hertz contact theory. The differential equations of the coupled system were solved by the Newmark integration method and the results including vertical and lateral displacements and forces were presented in the time domain. Since the purpose of this dissertation is to quantify the effect of track and vehicle condition on vibration level, rail defects were also taken into account and rail random irregularities for the vertical profile, Gauge, alignment and cross level (super elevation) were incorporated into a numerical solution. The results of the study show the effect of track and vehicle parameters on the response of the vehicle, track, and substructures. Since Florida and some other states in the United States are very prone to hurricanes, an investigation was conducted into the effect of wind speed on vehicle stability. For this purpose, a curved beam was modeled to consider the influence of track curvature, cant deficiency, wind speed and train speed simultaneously. The results from the study show the maximum allowable values of train speed and axle load for different wind speeds. The findings can be used to decide under what circumstances there is a risk of vehicle overturning and how to avoid it.

During the 50 years of existence of high speed railways, the track structure solutions have developed both in number and in type. As of today, in case of conventional railway, there are 2 main types one could mention: ballasted and ballastless track solutions. However, there is no standardized procedure for choosing between these systems and between their respective variants, the decision is made on a case-by-case basis. This thesis aims to create a generic framework for decision making, primarily taking into account technical details. The model, the input parameters and variables can be easily adjusted and customized based on national standards, practices or other considerations, but the primary focus in the thesis have been the current Swedish regulations. The thesis has an overview on the influencing factors and attempts to include the most crucial ones of these into a decision-making model. This model compares 3 alternatives, namely the ballastless alternative, the ballasted alternative and the alternating system option, in which case the track system selection happens based on local factors, such as geotechnical conditions. These are considered and evaluated through Fuzzy logic, which supports the system selection affected by various sources of uncertainty. The decision is finally made through an LCC calculation. In order to handle the great uncertainties in the data used in the LCC, a Monte Carlo simulation is performed. The main added value of the thesis is considered to be the methodology for choosing the systems based on life-cycle cost after careful technical evaluation. This approach might provide basis for decision for track systems of high speed rail lines.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1997.<br>Vita.<br>Includes bibliographical references (leaves 174-175).<br>by Masao Shimatake.<br>M.S.

The Swedish Transport Administration has been giving the task to set up a new standard for concrete slabs for the new high-speed railway in Sweden. They are demanding that the concrete slabs must be dimensioned according to the German Beton Kalender 2000. This report will explore the results when dimensioning a slab track, according to the German Beton Kalender 2000. Moment capacity, deformation, and crack width are calculated according to two structural theories, namely slab and beam theory, and a comparison between the two methods is presented.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California<br>As renewal interest in building vehicles based on hypersonic technologies begin to emerge again, test ranges anticipating in supporting flight research of these vehicles will face a set of engineering problems. Most fundamentals of these will be to track and gather error free telemetry from the vehicles in flight. The first series of vehicles will likely be reduced-scale models that restrict the locations and geometric shapes of the telemetry antennas. High kinetic heating will further limit antenna design and construction. Consequently, antennas radiation patterns will be sub-optimal, showing lower gains and detrimental nulls. A mobile system designed to address the technical issues above will be described. The use of antenna arrays, spatial diversity and a hybrid tracking system using optical and electronic techniques to obtain error free telemetry in the present of multipath will be presented. System tests results will also be presented.

International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada<br>The system covered in this paper is the Telemetry Processing System (TPS) designed and installed for processing data acquired from high speed test sleds at Holloman AFB, NM. Because this facility operates as a test range, testing sleds from many different agencies for a variety of different purposes, prior knowledge is not always available concerning the instrumentation on the test sled to be used and therefore the type of data retrieval and processing required. The TPS must then be capable of acquiring and processing multiple data types including PAM and PDM, multiple FM streams (72 channels) and high speed PCM (4 channels) . Additionally, the requirement has been imposed for 3.2 Msample/sec analog-to-digital conversion capability for high resolution measurement of certain analog data (10 channels). When the above data are multiplexed with three time sources, eight channels of sled positional information and operated at maximum rate, the raw data exceed 15 Mbytes/sec. Depending on the scheme used to tag the samples, time stamp the data, and convert the data to engineering units, the processed data rate could have exceeded 100 Mbytes/sec and therefore the reasonable limit of existing telemetry processing technology. The TPS requires not only the capability to acquire and record this very high rate data, but also the realtime display of selected measurements. Further, the acquired data must be readily available immediately after the test for quick look evaluation, and for data selection for archival storage. This paper will explore the design process that allows the system to meet these requirements using mostly off-the-shelf or only slightly modified equipment by making clever compromises and effective use of stream separation. The paper will explore the hardware and software considerations which were examined and the solutions implemented in the final design. Development and integration of this system are currently underway, with delivery scheduled for later this year.

On the 19th of February 2010, the Ministry of Transport and Communication presented the Norwegian National Rail Administration with the task of assessing different aspects of the future of high-speed rail in Norway. The report, the Norwegian High-Speed Rail Assessment (NHSRA), consist three separate evaluations where the climate assessment by Bergsdal et al. (2012), motivated this thesis. Results from the report identify the railway infrastructure as the dominant emission source for the corridor, with the length of tunnels representing the determining factor. Simultaneously, an ongoing debate is comparing the safety and performance of track and tunnel technologies traditionally used in Norway to that of foreign tunnelling technology such as the drill and blast method which apply a full cast (European method), and a double shielded tunnel boring machine (TBM). The newest development in track technology is the slab track, which is now evaluated for tunnels and bridges in Norway (Jernbaneverket 2011). This thesis contributes to the ongoing debate concerning the construction of infrastructure for high-speed rail in Norway, by emphasizing the environmental impact of several relevant technologies and geological conditions. The assessment includes an evaluation of the impact of different tunnelling and track technologies, calculated for operation speeds of both 250km/h and 330km/h. Further, the environmental impact of different levels of support work and grout is assessed. In addition, this thesis includes a sensitivity analysis of the impact of service life for railway components. The assessment is calculated for two functional units: one meter tunnel and tunnel track, and for the case corridor, the potential high-speed rail corridor between Oslo-Stavanger, estimated for 250km/h obtained from the NHSRA by Bergsdal et al. (2012).Our results from this assessment account for the use of cement, steel and copper as the environmentally most important materials. Among the railway components, the tunnel lining and grout constitute the highest emission level of the case corridor. The different technical alternatives are compared against the technologies traditionally applied in Norway, and an average level of support work, which represents the baseline results of this thesis. Our results indicate that the double shielded tunnel-boring machine is the technology that contributes to the highest increase of emission level compared to baseline. Further, the variables that hold the greatest potential of reducing total emission level is the installation of slab track in tunnels and bridges, and level of grout in the tunnel construction.

When a train enters a bridge, passenger sitting inside will feel a sudden bump in the track, which not only affect the riding comfort of the passengers but also put a dynamic impact on the bridge structure. Due to this impact force, we have very serious maintenance problems in the track close to the bridge structure. This sudden bump is produced when train travelling on the track suddenly hit by a very stiff medium like bridge structure. In order to reduce this effect, transition zones are introduced before the bridge so that the change in stiffness will occur gradually without producing any bump.   This master thesis examine the effect of track stiffness on the bridge dynamic response under different train speeds from 150 to 350 km/h with interval 5 km/h and also estimate the minimum length of transition zones require to reduce the effect of change in stiffness on the bridge. Study also gives us some guidelines about the choice of loading model of the train, location of maximum vertical acceleration, effect of ballast model on the results and minimum length of transition zone needs to include in the bridge-track FE-model, for dynamic analysis of the concrete bridges. To carry out this research MATLAB is used to produce an input file for the ABAQUS FEM program. ABAQUS will first read this file, model the bridge and then analysis the bridge. MATLAB will again read the result file, process the result data and plot the necessary graphs.   The Swedish X2000 train is used for this study, which has been modeled with two different methods: moving load model and sprung mass model, in order to see the difference in results. For verification of the MATLAB-ABAQUS model, a 42m long bridge is analysed and results are compared with known results. In this study, concrete simply supported bridges with spans of 5, 10, 15, 20, 25 m have been analysed.