High Speed Train Research Papers (original) (raw)

The design of new high-speed railway lines requires longer and more numerous tunnel sections, where aerodynamic effects limit the maximum allowed train velocity for a given tunnel cross-section area. These effects influence the train power requirement, the traction energy costs and the pressure wave amplitude: the knowledge of the unsteady aerodynamic field around the train is therefore essential to the optimum choice of a tunnel configuration, and mainly of the cross-section diameter and of the presence and position of pressure relief ducts. In this paper, the aerodynamic phenomena generated by a train traveling at high speed through a long tunnel of small cross-section are analyzed by means of quasi one-dimensional numerical simulations of the air flow induced by a train traveling at 120 m=s in a tunnel connecting two stations 60 km apart. Several tunnel configurations at high blockage ratio are discussed, together with the positive and negative effects of pressure relief ducts and of partial air vacuum. Aerodynamic phenomena are evaluated in terms of drag, pressure wave amplitude and shock wave onset on the train tail. Results suggest that configurations consisting of twin tunnels connected by pressure relief ducts near stations and operated under partial vacuum should be preferred. #

- by
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- Mechanical Engineering, Civil Engineering, Numerical Simulation, Air flow

High-speed trains could be used to solve two different accessibility problems. In the first case, where a point to point link is dominant, they are a potential substitute for air travelling. In the second case it links together many cities and, hence, creates a new type of region or corridor with a high interregional accessibility. One important hypothesis for the discussion in this paper is the degree to which cities that are linked together into a band of cities by means of a high-speed train connection are transformed to an extended functional region or in other words an integrated corridor economy. This paper particularly examines economic integration in a corridor economy in the short, medium and long term. In considering the short-term perspective we discuss not only the integration of goods and service markets but also the integration of labour markets and markets for shopping, private services and leisure activities. The discussion of the medium term perspective is concentrated on the relocation of households and firms within a high-speed train corridor. To study the long-term integration effects of a high-speed train corridor we maintain that the analysis must be conducted using a genuinely dynamic model for the specialisation of production and, hence, for trade with and transport of goods and services and consequently transport of people.

Participatory SWOT-analysis for the spatial impact study Railway Zone Breda: a case study (assigned to theme K) This paper on the spatial impact study Railway Zone Breda describes a participatory SWOTanalysis for assessing the impact of a large scale innercity infrastructural project on adjacent residential neighbourhoods in which residents and other stakeholders, policy officials of the municipality of Breda and researchers participated. This large infrastructural project includes the transformation of the present railway station into a shuttle station for the high speed train Amsterdam -Paris.

- by Mike Duijn
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- Situated Cognition, Policy Analysis, Policy making, Impact Analysis

When the construction of the Lyon-Turin segment of the new European high-speed rail network was first publicly announced at the beginning of the 1990s, it immediately found fierce opposition from the inhabitants of Susa Valley, Italy, one of the areas to be cut across by such infrastructure. At issue were the project’s potential environmental impact and its consequences on public health. This study intends to clarify environmental risk perception and public debate between the national government, local advocacy groups, and the inhabitants of Susa Valley. Two major phases of public reaction were identified: (1) an initial rebellious period of no real dialog among the project’s major stakeholders (exemplified by the popular “No TAV” [No High Speed Train] movement), followed by (2) a yielding period of intense multilateral negotiations centered on the activities of the “Lyon-Turin Environmental Observatory.” The results of a qualitative cross analysis of the residents’ perception of the proposed high-speed rail revealed that public acceptance of risk in Susa Valley was influenced by the characteristics of hazards perceived by the residents and by the communicative approach used by the project’s various stakeholders. It also emerged that early dialog among all the parties involved was critical in forming a personal viewpoint on risk, which, once consolidated, defied new information and perspectives. Likely, a greater and earlier care taken by the other stakeholders to inform and consult the local population about the railway would have greatly eased the public debate.

- by Fausto Marincioni and +1
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- Human Ecology, Public Opinion, Public Relations, Politics

The aim of this paper is to give a number of methodological and theoretical indicators concerning the contribution of ergonomists to the execution of design projects of new products. Within the context of a design project, the present work therefore describes the studies and ergonomic analyses that can be undertaken during each phase of the design process from a design model based on concurrent engineering. Encompassing the design of the driving cabin of the new generation of high-speed trains (TGV-NG), this paper, through the ergonomic study of a number of technical sub-systems of this product, illustrates the advisory role of the ergonomist who, within the collective design process, ensures that the specific nature of the ''human factor'' is fully integrated into the design approach. Thus, throughout the design process, the ergonomist is called upon both to advise the designer on the characteristics of the target users and, on the basis of a ''desirable future activities'' approach, to help him or her assess the consequences of the design choices made. Ergonomics is described consequently, as an innovation and safety factor. # Safety Science 41 www.elsevier.com/locate/ssci 0925-7535/02/$ -see front matter # 2002 Elsevier Science Ltd. All rights reserved. P I I : S 0 9 2 5 -7 5 3 5 ( 0 2 ) 0 0 0 3 8 -3

- by Samuel Gomes
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- Engineering, Human Factors, Concurrent Engineering, Product Design

In high-speed trains, current collection from the overhead line is assured by an articulated suspension system called the "pantograph." Contact wires and overhead line are flexible systems that are subjected to oscillations that have to be compensated for a satisfactory quality of current collection. In high-speed railway applications, this technical problem is very important since higher traveling speed involves higher oscillations of the catenary. A feasible solution to improve current collection quality is to optimize the dynamical response of the pantograph suspension system through an active or semiactive suspension system. The authors of this paper have worked and cooperated with a team composed of members of Trenitalia SPA (main Italian railway company), Italcertifer (an Italian R&D agency), and many Italian Universities (Università di Firenze, Politecnico di Milano, Università di Pisa, and Università di Napoli) to the development of a prototype of an innovative railway pantograph for Italian high-speed lines. The authors have designed the layout of the control system (actuation system, sensors, drive and control algorithm, etc.). The proposed control strategy has been successfully calibrated with experimental tests. Testing procedures and experimental results are shown in order to demonstrate the feasibility of the proposed solution and performances achieved by the first Trenitalia prototype, the T2006 pantograph.

- by Benedetto Allotta
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- Mechanical Engineering, Control system, Manufacturing Engineering, Oscillations

With the advent of high-speed trains, there is a renewed interest in the rail track-vehicle interaction studies. As part of an ongoing investigation of the track system optimisation and fatigue of the track components, a dynamic model is developed to examine the vertical interaction of the rail track and the wagon system. Wagon with four wheelsets representing two bogies is modelled as a 10 degree of freedom subsystem, the track is modelled as a four-layer subsystem and the two subsystems are coupled together via the non-linear Hertz contact mechanism. The current model is validated using several field test data and other numerical models reported in the literature by other researchers. Ó

- by Manicka Dhanasekar
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- Engineering, Contact Mechanics, Steady state, Timoshenko Beam

This paper summarizes the analysis of roughly 6 h of data from four instrumented wheelsets running at speeds of up to 240 km/h on the same Amtrak Acela trainset. Comparisons are made between power car and coach car traction values, L/V ratio, and damage (wear and RCF). The propensity for wheel climb is found to be roughly the same for power car and coach car wheels. The wear and RCF damage, as evaluated through the T␥ index, is about 50% higher for the two power car wheelsets than for the two coach car wheelsets. The peak traction coefficient on the Amtrak system is measured to have a value of about 0.65 at low speeds, declining to about 0.22 at 200 km/h. These levels are much higher than those found in the literature for high-speed trains.

- by Eric Magel
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- Materials Engineering, Mechanical Engineering, Wear, High Speed

A formulation of three-dimensional dynamic interactions between a bridge and a high-speed train using wheel-rail interfaces has been developed. In the interface, contact loss is allowed, the vertical contact is represented by finite tensionless stiffness and the lateral contact is idealized by finite contact stiffness and creepage damping. Such stiffness and damping are nonlinearly dependent on normal contact force. The relative rotations of a wheelset to the rails about its vertical and longitudinal axes are included. Bridge eccentricities and deck displacement due to torsion are accounted for in bridge deck modeling. A numerical algorithm using separate integrations for bridges and trains, and iterations for interface compatibilities is established. A case study of a ten-car train passing over a two-span continuous bridge at various speeds and rail irregularity wavelength ranges is analyzed. The responses of the bridge, carbodies and wheelsets are investigated for their behavior, acceptability and relations with the wavelengths. Analytical and numerical evaluations of resonant speeds are in good agreement, and the exit span vibration is more amplified than the entrance one at those speeds. The computed relative displacements of all wheelsets to the rail facilitate an explicit assessment for derailment risk.

- by van nguyen dinh
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- Civil Engineering, Structures and Fire Engineering, Dynamic Analysis, Case Study

In recent years, the high-speed train (HST) network has developed considerably, unfortunately increasing vibration nuisances in its neighbourhood. This paper aims to present some vibration measurements collected on a Belgian site located between Brussels and Paris/London and travelled by the Thalys and Eurostar high-speed trains, and to compare them with the results obtained by a recently developed model, involving the compound vehicle/track/soil system. Assuming that the soil can be reasonably decoupled from the track, the approach first considers the train/track subsystem. The latter is studied by combining a multibody model of the vehicle with a finite element model of the track, both so far limited to the vertical motion. The ground forces given by this first simulation are then applied on a finite/infinite element model of the soil subsystem, where the infinite elements are placed on the border of the mesh in order to properly represent an unbounded domain. Both simulations are performed in the time domain, offering the opportunity to include non-linearities. The good correspondence between numerical and experimental results shows that the model is reliable for predicting the vibration produced by the highspeed vehicles. Finally, the paper presents some cases showing the importance of including the complete vehicle and the soil layering to the model.

- by O. Verlinden and +1
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- Civil Engineering, Geophysics, Vibration, Finite Element Analysis

Long distance railway transport is more energy efficient and generates fewer environmental impacts that flying and automobile travel. One strategy for increasing rail use is to replace flying and driving by introducing high speed rail systems and other rail service improvements; however, even with these improvements rail travel may take too long for certain trips. Therefore, another strategy is to increase the use of rail for at least part of a trip; for example, by replacing a short-haul flight. This could be done by improving intermodal connections (e.g. flight to train connections at an airport) or by using rail on the outbound trip and air on the return trip (or vice versa). In 2005, CityNightLine, a European night train operator, and Swiss International Airlines developed a product that combined a night train trip with a flight. This product provided an ideal opportunity to evaluate the socio-institutional barriers towards intermodal journeys because it eliminated the physical transfer (there was no mid-trip transfer from train to plane). The research consisted of performing user and non-user surveys to obtain information about the combined product. This information was used to evaluate the socio-institutional barriers to intermodal transport using a new product adoption structure developed by Rogers. The research found that an effective Internet-based multi modal transport information and reservation system is needed to successfully increase rail travel. This system should provide accurate and complete information about all travel alternatives in a simple package and should enable customers to purchase a single ticket for the entire trip (including local public transport). The paper includes recommendations for further research.

- by Andrew Nash and +2
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- Civil Engineering, Public Transport, Case Studies, Urban And Regional Planning

The corridor concept occupies a prominent place in several European reports. The creation of corridors is related to Ôspace of flowsÕ and Ôspace of placesÕ. The analysis of the case of the Brussels high speed train station makes it utterly clear that the space of flows often wipes out and replaces the space of places. A new financial and managerial elite is installed at the cost of the local population. This article provides elements of an alternative, open, fair and transparent approach. This calls for innovations in the governance structure as well.

- by Tom Coppens
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- Human Geography, Subsidiarity, Governance, Transport Geography

Failure mode effects and criticality analysis (FMECA) is a widely used technique to improve products and processes safety and reliability in different contexts, such as automotive, aviation, computer science, etc. FMECA approach is based on a qualitative/quantitative analysis of a system (product or process) and its components in order to identify the most critical elements for system operability and safety through the evaluation of failure mode causes and effects.

- by Alessandro Brun
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- Mechanical Engineering, Applied Mathematics, Fuzzy Logic, Production Management

The material characterization described in the paper is aimed at the structural design of the front shield for a high speed train made of composite material. A sandwich structure was considered, made of glass fiber epoxy face sheets with a polymeric foam core. Initially, the material properties and the rate sensitivity of the skin and core materials were investigated through a series of static and quasi-static tests. Static and dynamic impact tests were then run on the sandwich structure. For all materials tested, no significant strain-rate effects were observed over the range of test conditions investigated in the study. Results show that the structural response of the sandwich depends primarily on the strength properties of the foam core material. The dynamic impact resistance of the sandwich structure was then substantially improved by adding a net of resin walls within the foam.

- by Giovanni Belingardi
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- Engineering, Structural Design, Composite Material, Composite structures

Purpose: This study compares the training characteristics and the physical profiles of top-class male and female Kenyan long-distance runners. Method: The subjects were 20 elite Kenyan runners: 13 men (10-km performance time: 10-km performance time of 28 min, 36 s Ϯ 18 s) and 7 women (32 min, 32 s Ϯ 65 s). The male runners were separated into high-speed training runners (HST: N ϭ 6) and low-speed training runners (LST: N ϭ 7) depending on whether they train at speeds equal or higher than those associated with the maximal oxygen uptake (vV O 2max ). All but one woman were high-speed training runners (female HST: N ϭ 6). Subjects performed an incremental test on a 400-m track to determine V O 2max , vV O 2max , and the velocity at the lactate threshold (vLT). Results: Within each gender among the HST group, 10-km performance time was inversely correlated with vV O 2max (rho ϭ Ϫ0.86, P ϭ 0.05, and rho ϭ Ϫ0.95, P ϭ 0.03, for men and women, respectively). HST male runners had a higher V O 2max , a lower (but not significantly) fraction of vV O 2max (FV O 2max ) at the lactate threshold, and a higher energy cost of running (ECR). Among men, the weekly training distance at vV O 2max explained 59% of the variance of vV O 2max , and vV O 2max explained 52% of the variance of 10-km performance time. Kenyan women had a high V O 2max and FV O 2max at vLT that was lower than their male HST counterparts. ECR was not significantly different between genders. Conclusion: The velocity at the V O 2max is the main factor predicting the variance of the 10-km performance both in men and women, and high-intensity training contributes to this higher V O 2max among men.

- by Pierre-Marie Leprêtre
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- Kenya, Running, Medicine Science, Oxygen Uptake

... H. Abu-Rub is with Texas A&amp;amp;amp;M University at Qatar, Doha 23874, Qatar (e-mail: haitham.abu-rub@ qatar.tamu.edu). ... 2008. [10] KM Al-Hussain, Dynamic stability of two rigid rotors connected by a flexible coupling... more

- by A. Lewicki
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- Engineering, Industrial, High Speed Train, Sensorless Control

- by Samuel Gomes
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- Engineering, Human Factors, Concurrent Engineering, Product Design
- by Gines De Rus
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- Human Geography, Public Opinion, Air Transport, Regional development

The increased speeds of modern trains are normally accompanied with increased transient movements of the rail and ground, which are especially high when train speeds approach some critical wave velocities in the track±ground system. These transient movements may cause large rail deflections, as well as structural vibrations and associated noise in nearby buildings. There are two main critical wave velocities in the track±ground system: the velocity of the Rayleigh surface wave in the ground and the minimum phase velocity of bending waves propagating in the track supported by ballast, the latter velocity being referred to as the track critical velocity. Both these velocities can be exceeded by modern high-speed trains, especially in the case of very soft soil where both critical velocities become very low. The discussion in this paper focuses on the effects of transient rail deflections on associated ground vibrations in the cases of train speeds approaching and exceeding Rayleigh wave and track critical velocities. The obtained theoretical results are illustrated by numerical calculations for TGV and Eurostar high-speed trains travelling along typical tracks built on soft soil.

- by Victor V Krylov
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- Mechanical Engineering, Soft Soil, Wave propagation, High Speed Train

This paper investigates the possibility of improving the performance of railway vehicle suspensions by incorporating a newly developed mechanical device known as the inerter. A comparative study of several low-complexity passive suspension layouts is made. Improved performance for the lateral and vertical ride comfort, as well as lateral body movement when curving are demonstrated in comparison with the conventional suspension layout. The constraints imposed are to maintain the same level of other performance metrics. The calculations and optimisations are based on linearised plan-view and side-view high-speed train mathematical models.

- by Jason Jiang
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- Engineering, Mathematical Sciences, Mathematical Model, High Speed Train

The dramatic increase in speeds of modern passenger trains makes it important to consider the vibrational impact of such trains on the built environment. In the author's earlier paper in which a quasistatic approach to the calculation of track deflection curves had been used ͓V. V. Krylov, Appl. Acoust. 44, 149-164 ͑1995͔͒, it had been shown that a very large increase in generated ground vibration level ͑about 70 dB, as compared to conventional trains͒ may occur if train speed exceeds the velocity of Rayleigh surface waves in the ground. Such a situation might arise, for example, with French TGV trains for which speeds over 515 km/h have been achieved. The present paper investigates the effect of track bending waves propagating in the system track/ground on railway-generated ground vibrations. It is shown that for train speeds approaching the minimal phase velocity of bending waves the level of generated ground vibrations is reduced. Theoretical results are illustrated by numerically calculated frequency spectra of ground vibrations generated by single axle loads traveling at different speeds and by TGV or Eurostar high-speed trains.

- by Victor V Krylov
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- Multidisciplinary, High Speed Train
- by Kwanjung Yee
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- Mechanical Engineering, Methodology, Response Surface Methodology, Optimization

In the paper it is presented the mathematical model of the useful movement of the high-speed trains. On the mathematical model basis it is built the structural diagram associated of the useful movement. The obtained structural scheme can be easily implemented in SIMULINK. An immediately example of the utilization of the useful movement model it constitutes the drawing of the movement diagrams, which it illustrates the dynamics aspect of the useful movement. Like application, by means of the SIMULINK model they are traced, on the basis of the traction and braking characteristics and of the imposed conditions of the route, the movement diagram of the high-speed train.

- by Mircea Drighiciu
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- Modeling, Simulation, Electric Vehicle, Mathematical Model

Estimation of disaggregate mode choice models to estimate the ridership share on a proposed new (or improved) intercity travel service and to identify the modes from which existing intercity travelers will be diverted to the new or upgraded service constitutes a critical part of evaluating alternative travel service proposals to alleviate intercity travel congestion. In Libya, people heavily relies on private cars for intercity trips increased traffic congestion and road accidents on intercity highways having been the negative impacts. The time is ripe for a policy to simultaneously improve intercity public transport and control car ownership. The aim of this study is to evaluate and analyze the influence on intercity mode choice by proposing a new intercity high-speed train system with high quality of services and new low-cost airline service, in order to reduce car use for intercity travel in Libya, and to enhance intercity road safety. Also, to develop a framework to model travel choice behavior in order to estimate intercity travel demand at nation-level in Libya. The collection of data is conducted through revealed and stated preference surveys handed out to intercity travelers between all major cities in Libya. Comprehensive questionnaires (Arabic and English) will be designed and distributed at airport terminals, bus terminals, and at gasoline stations located midway between the cities under study. The results are hoped to assist decisionmakers on all levels to wisely allocate resources to public transportation improvement, and to reduce road accidents on intercity highway and enhance road safety.

- by Rahmat Abdullah
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- Information Technology, Road safety, Public Transport, Atmospheric Modeling

One effect of the regulatory reforms in the transportation sector is that private companies increasingly participate in the investments in new transportation systems. These investments may amount to very large sums in the coming 10-year-period. There are several different ways to categorise these projects, but with a common name they may all be viewed as Public- Private Partnerships (PPPs). Some

- by Staffan Hultén and +1
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- Public sector, Intelligent Transport System, Public Private Partnership, Environmental Concern

Compression waves generated by trains entering a tunnel travel toward the opposite portal, where they are partly reflected back in the tunnel as expansion waves and partly radiated outside as micro-pressure waves. The intensity of the micro-pressure waves is related to the pressure gradient of the oncoming wave that, during its propagation within the tunnel, can either become steeper or smoother, according to the balance between viscous, thermal and nonlinear effects. Under the worst conditions, micro-pressure waves can become cause of concern producing noise and vibrations in the environment close to the tunnel exit.

- by Luigi Vigevano
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- Engineering, Gas Dynamics, Physical sciences, Sound and Vibration

Tabares (1J. Lucas (3> (1) CEDEX. (2) CIEMAT. (3) ELYTT Energy. Madrid (Spain).

- by L. García-Tabarés
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- Engineering, Power Electronics, Machine Design, Control system
- by Keon Jang
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- Mobility, Wireless Network, Measurement, Rich Internet Application

A pricing methodology adapted to specific railroad infrastructures and the trains that use them is one way to ensure that railroad networks used by several different operators are used optimally. The diversity of railway networks (new lines and old lines) and services (long-distance and suburban passenger trains, freight trains, etc.) make it difficult to develop such a pricing methodology. This paper proposes a pricing methodology for a mixed use rail network designed to encourage efficient network use and thereby contribute to development of a sustainable transport system. The proposed methodology considers internal and external costs. It could be applied by different network operators (e.g. national rail networks) differently based on policy objectives. One feature of the pricing methodology is that it would partially subsidize a rail service's infrastructure charges based on the savings in external costs when a certain level of demand is met by railroad rather than road. The proposed methodology also considers the rail service operator's willingness to pay and public service issues. The paper describes how the proposed methodology would be applied for different train services. The conclusions show that under the proposed pricing methodology, charges would increase in the following order: suburban, regional passenger trains and freight trains (lowest) to high-speed trains (highest).

- by Andrew Nash and +1
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- Civil Engineering, Sustainable Transportation, Methodology, Urban And Regional Planning

In this study, the dynamic response of a catenary system that supplies electrical power to high-speed trains is investigated. One of the important problems which is accompanied by increasing the speed of a high-speed rail, is the performance of stable current collection. Another problem which has been encountered, is maintaining continuous contact force between the catenary and the pantograph without loss of panhead. The dynamic analyses of the catenary based on the Finite Element Method (FEM) are performed to develop a pantograph suitable for high speed operation. The static deflection of the catenary, the stiffness variation in contact lines, the dynamic response of the catenary undergoing the force of a constantly moving load and the contact force were calculated. It was confirmed that a catenary model is necessary to study the dynamic characteristics of the pantograph system.

- by Tong-Jin Park
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- Mechanical Engineering, Applied Mathematics, Finite element method, System Analysis

The Global System for Mobile Communications-Railway (GSM-R) system is currently deployed in Europe in order to ensure the interoperability of the high-speed trains. Knowing that data related to control and command will be transmitted to trains through this communication system, the immunity of the GSM-R system against electromagnetic disturbances on board trains has to be certified. After a background about the GSM-R communication system, we will present in detail the typical disturbances that can affect this system in the railway environment. Significant differences between these disturbances and the test signals defined in the current European electromagnetic compatibility standards will be highlighted. The criteria that can be employed to evaluate the immunity of the GSM-R transmissions will then be discussed. Finally, new test signals and immunity test bench will be presented in order to expose the GSM-R transmissions to noise scenarios representative of the railway environment. Different immunity results will be presented and analyzed.

- by Virginie Deniau and +1
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- Electromagnetic Compatibility, Mobile Communication, Electromagnetic Interference, Communication System

In order to better understand the heave observed on the railway roadbed of the French high-speed train (TGV) at Chabrillan in southern France, the swelling behaviour of the involved expansive clayey marl taken from the site by coring was investigated. The aim the study is to analyse the part of heave induced by the soil swelling. First, the swell potential was determined by flooding the soil specimen in an oedometer under its in-situ overburden stress. On the other hand, in order to assess the swell induced by the excavation undertaken during the construction of the railway, a second method was applied. The soil was first loaded to its in situ overburden stress existing before the excavation. It was then flooded and unloaded to its current overburden stress (after the excavation). The swell induced by this unloading was considered. Finally, the experimental results obtained were analyzed, together with the results from other laboratory tests performed previously and the data collected from the field monitoring. This study allowed estimating the heave induced by soil swelling. Subsequently, the part of the heave due to landslide could be estimated which corresponds to the difference between the monitored heave and the swelling heave.

- by Anh Minh Tang
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- Engineering, Civil Engineering, Geology, Engineering Geology

This paper evaluates gains in efficiency produced by the use of efficient designs to analyze stated choice (SC) data. Based on a standard experiment used in a previous research, we compare the efficiency of this design with that of the efficient design obtained according to the minimization of the D-error, considering different modelling strategies. The experiment was conducted in the

- by Raquel Espino
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- Parameter estimation, Revealed Preference, High Speed Train, Mode choice

Total number of pages = 65 Total number of figures = 25 Total number of tables = 5 Abstract The study of railway tracks under high speed trains is one of the most important researches in the domain of transport. A reduced scale experiment with three sleepers is presented to study the dynamic behavior and the settlement of ballasted tracks. A large number of trains passing at high speeds are simulated by signals, applied with the help of hydraulic jacks, having the shape of the letter M and representing the passages of bogies on sleepers. This experiment offers results such as displacements, accelerations, pressures and settlements that allow to better understand the dynamic behavior of a portion of a ballasted railway track at reduced scale and to estimate the settlement versus the number of load cycles. It was found that mechanical properties such as the global stiffness of the track can have important variations

- by Karam Sab
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- Engineering, Physical sciences, Sound and Vibration, High Speed

Optical thermometers have been widely investigated. Here, the temperature behavior of second harmonic generation (SHG) in periodically poled lthium niobate (PPLN) substrates is analyzed; indeed, the QPM tuning in PPLN devices and the obtained SHG efficiency depend on the crystal thermal expansion and dispersion, particularly in the case of guided propagation. Therefore, such devices are suitable to realize optical thermometers for demanding applications. This investigation originated with the request of a thermometer to be installed on the pantographs of high-speed trains. Therefore, it must be sturdy and reliable, but it has even to work in an EMD environment. The temperature behavior of the SHG was theoretically modeled and experimentally validated at 1550 nm, in both bulk propagation and APE channel waveguides. In the first case, by using a 10-mW source, which was obtained from a laser diode and a fiber amplifier, an accuracy of 0.3 C was found. The pump power was about three orders of magnitude smaller in guided propagation. In view of testing on the trains, our investigation resulted in the design of a device without mechanical contacts with the input and output fibers. Since it works in free propagation, there are no serious alignment and packaging problems. The performances, which are expected to be the same of our tests, widely satisfy all the requirements for working effectively in a strongly hostile and EMD environment and for giving accurate measurements on a wide range of temperatures.

- by Francesco Prudenzano and +2
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- Mechanical Engineering, Nonlinear Optics, Sensors, Second Harmonic Generation

International interest is growing for improving performance of the rail transport system. A crucial problem for railway companies is to prevent damages to the overhead line equipment and to pantographs. A brief overview of our research activities is addressed, in the fields of active pantographs and advanced methods for measuring the quality of the current collection for high-speed trains. The pantograph-overhead contact wire interaction is investigated by using a phototube sensor, wavelet transform applied to the line current and infrared camera. The results obtained are relevant for monitoring the quality of the current collection and for a predictive maintenance of the pantograph and of the contact line.

- by Luca Sani
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- Intelligent Transport System, Wavelet Transform, Active Control, Infrared

This paper presents a feasibility study of a technique for measuring the distance between two trains following one another through a tunnel at a distance of several kilometers. A preliminary series of measurements was performed in the Channel Tunnel, between France and England, in order to characterize the propagation of high-frequency waves in such an environment, with the primary objective of showing the influence of frequency on received power. After a description of the main results of this first phase, a measurement system based on correlation techniques and employing pseudorandom sequences is presented. The last section of this paper reports the test results produced by the prototype; these results show promise in terms of range and measurement accuracy.

- by P. Laly
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- Engineering, Technology, Feasibility Study, High Frequency

- by Giovanni Belingardi
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- Engineering, Structural Design, Composite Material, Composite structures

There is a growing demand for high mobility and ultrafast internet/data services which drives the motivation for free space optical (FSO) communications for high speed trains. Here we present an FSO link for the ground-to-train communications, which consists of optical transceivers positioned alongside the track and on the roof of the train. When the train moves at a high speed, the airwave induced turbulence degrades the FSO link performance. In this paper the effect of turbulence is experimentally investigated and compared with the case of no turbulence.

- by Rupak Paudel
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- Free Space Optics, Optical Sensor, High Speed, High Speed Train

The recent advent of high speed trains introduces
new mobility patterns in wireless environments. The LTE-A
(Long Term Evolution of 3GPP - Advanced) networks have
largely tackled the Doppler effect problem in the physical layer
and are able to keep wireless service with 100Mpbs throughput
within a cell in speeds up to 350 km/h. Yet the much more
frequent handovers across cells greatly increases the possibility
of service interruptions, and the problem is prominent for
multimedia communications that demand both high-throughput
and continuous connections.
In this paper, we present a novel LTE-based solution to
support high throughput and continuous multimedia services
for high speed train passengers. Our solution is based on a
Cell Array that smartly organizes the cells along a railway,
together with a femto cell service that aggregates traffic demands
within individual train cabins. Given that the movement direction
and speed of a high-speed train are generally known, our Cell
Array effectively predicts the upcoming LTE cells in service, and
enables a seamless handover that will not interrupt multimedia
streams. To accommodate the extreme channel variations, we
further propose a scheduling and resource allocation mechanism
to maximize the service rate based on periodical signal quality
changes. Our simulation under diverse network and railway/train
configurations demonstrates that the proposed solution achieves
much lower handover latency and higher data throughput, as
compared to existing solutions. It also well resists to network and
traffic dynamics, thus enabling uninterrupted quality multimedia
services for passengers in high speed trains.

- by Ouldooz Baghban Karimi
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- Distributed Computing, Multimedia, Scheduling, Resource Allocation

In large steel fabrication industries such as shipbuilding, and high-speed train guideways, the problem of residual stresses and overall distortion has been and continues to he a major issue. In the last few decades, various research efforts have heen directed at the 'control of the welding process parameters aiming to reduce distortions and residual stresses. Yet. in actual practice, large amounts of resources are still required to rework welds. These costs increase production costs and delay work completion.

- by Victor Mucino
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- Finite Element Methods, Heat Transfer, Neural Networks, Finite element method

ABSTRACT: 3D geometric modelling is a powerful tool to better understand geology. It allows to check and validate the consistency of the separate 1D or 2D data interpretations. Building a 3D model is also a way to share and communicate a... more

- by P. Calcagno
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- Geometric Modelling, Mathematical Geology, Geometric model, Data Interpretation

Results of numerical investigations of high Reynolds number¯ows past a simpli®ed train geometry under dierent yawing conditions are summarised. Variations of the incidence¯ow angle from parallel to normal with respect to the direction of the forward train motion resulted in the development of distinctively dierent¯ow patterns. To compute numerically the dierent¯ow structures, the threedimensional Reynolds-averaged Navier±Stokes equations, combined with the k±E turbulence model, were solved on a multi-block structured grid using a ®nite volume technique. The pressure±velocity ®elds were coupled using the SIMPLE algorithm. Despite the geometrical simpli®cations of the computed train con®guration, the resulting¯ow ®elds show signi®cant complexities. #

- by Michael Breuer
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- Mechanical Engineering, Applied Mathematics, Numerical Analysis, Finite Volume

This paper covers some of the work carried out in the planning of the Global System for Mobile Communication for Railway (GSM-R) of the tunnels on the new high-speed trains in Spain. Solutions based on distributed antenna systems have been tested by installing several 900-MHz transmitters inside and outside of a 4000-m tunnel and measuring the propagation in different conditions. The measurements have been used to model the effects of tunnel propagation, including curves, trains passing from the outside to the inside, and the effect of two trains passing inside the tunnel. All cases have been tested by comparing solutions using isofrequency and multifrequency distributed transmitters inside the tunnel. The improvements of signal-to-noise ratio and the reduction of the blocking effects of two trains passing have demonstrated the advantages of using isofrequency distributed antenna systems in tunnels. Finally, a complete propagation model combining both modal analysis and ray tracing has been applied to predict the propagation loss inside and outside these tunnels, and results have been compared with the measurements. The model has proven to be very useful for radio planning in new railway networks.

- by Javier Cruz
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- Engineering, Technology, Modal Analysis, Ray Tracing

Internet access for highly mobile users in high-speed trains or cars, underground walkways and tunnels is often challenged by intermittent connectivity with short and unpredictable connectivity opportunities. In such opportunistic communication scenarios, utilizing these connectivity opportunities to the best potential for the mobile user can be crucial to achieve an acceptable overall perceived service quality. When wireless access networks are shared between mobile and non-mobile TCP users, this objective can be difficult to achieveespecially considering the long-term throughput balance.

- by Carsten Bormann
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- Mobile Computing, Computer Simulation, Global, Internet Access

Citation: ZAMZURI, H., ZOLOTAS, A.C. and GOODALL, R.M., 2008. Tilt control design for high-speed trains: a study on multi-objective tuning approaches. Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility, 46(S1), pp. 535-547. This paper presents work on a hybrid fuzzy control scheme for improving the performance of tilting trains using a nulling-based tilt strategy. Two multi-objective Genetic Algorithm tuning methods (MOGA and NSGAII) were employed to optimise both the fuzzy output membership functions and the controller parameters. The objective functions incorporated the tilt response and roll gyroscope signals for the deterministic (curved track) profile, and lateral acceleration for the stochastic (straight track) profile. Simulation results discuss the effectiveness of using the presented techniques for tuning the fuzzy control scheme via multiple objectives. The proposed scheme is compared with the conventional nulling-tilt approach and a manually-tuned fuzzy controller.

- by Argyrios Zolotas
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- Engineering, Intelligent Control, Optimization techniques, Tilting theory

The multiple access solution in an IMT-Advanced mobile radio system has to meet challenging requirements such as high throughput, low delays, high flexibility, good robustness, low computational complexity and a high power efficiency, especially in the uplink. In this paper a novel multiple access scheme for uplinks denoted as B-IFDMA is presented. We show that this scheme is able to provide equal or better error rate performance than the Single-Carrier Frequency Division Multiple Access (SC-FDMA) schemes IFDMA and LFDMA, when considering realistic channel estimation performance at the receiver and no reliable channel state information at the transmitter. We also show that B-IFDMA provides better amplifier efficiency than OFDMA and can provide better end-to-end energy efficiency than IFDMA and LFDMA. Moreover, the scheme shows a promisingly high robustness to frequency-offsets and Doppler spread. Thus, this scheme can be regarded as a promising solution for the uplink of future mobile radio systems.

Resumen. Entre los elementos que el tren de alta velocidad española emplea en el sistema de sujeción del carril a la traviesa se encuentran varios componentes estructurales fabricados con materiales compuestos de matriz termoplástica, PA 6.6, y reforzados con fibra corta de vidrio. Estos componentes se encuentran sometidos continuamente a esfuerzos dinámicos de naturaleza cíclica como consecuencia del paso de las ruedas del tren. Para la caracterización ante este tipo de esfuerzos, en estudios previos se ha analizado la adaptación del método Locati a este tipo de materiales, lo que supone un ahorro importante de tiempo y probetas a ensayar. El método Locati consiste en la aplicación de bloques de un número de ciclos determinado bajo un nivel de esfuerzo constante que se irá incrementando paulatinamente al ir superando cada uno de los escalones. A medida que se aumenta la carga, llegará un momento en el que se alcanza el fallo por fatiga. Este nivel de esfuerzo, no coincide con el límite de fatiga del material, por lo cual la dificultad del método radica en la búsqueda de la correlación entre dicho parámetro y los resultados aportados por el ensayo. En este trabajo se propone un modelo para la identificación de las condiciones críticas a través de un estudio de la evolución de varios parámetros entre los que se encuentran la energía almacenada y disipada en cada uno de los ciclos de carga, así como del desfase entre las señales de carga y deformación. Estos parámetros comentados, actuarán como indicadores de la situación en la que la temperatura del material, como consecuencia del calor generado internamente por efecto de la carga repetitiva, alcanza valores similares a los de la temperatura de transición del material, momento a partir del cual el material comienza a adquirir deformaciones crecientes que desembocan en un fallo por fatiga.

- by Jorge Polanco
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- High Speed Train