scholarly journals Railway infrastructure in earthquake affected areas

2020 ◽  
Vol 72 (10) ◽  
pp. 905-921
Keyword(s):  
Track Structure ◽  
Safe Operation ◽  
Rail Vehicles ◽  
Railway Infrastructure ◽  
Longitudinal Resistance ◽  
Earthquake Action ◽  
Track Substructure ◽  
Seismic Impact ◽  
Small Deformations ◽  
Rail Traffic

In the case o seismic impact on rail infrastructure, even small deformations or damage to track structure can compromise safe operation of rail traffic. Damage can affect track substructure or permanent way of the track, but also the electrification system and safety-signalling devices. Ballast prism will suffer damage in case of greater intensity earthquakes, resulting in the reduction of lateral and longitudinal resistance of track structure. Earthquake action may also cause derailment of moving rail vehicles. Operation of rail vehicles also causes certain levels of vibrations, and so an analysis of subsequent effects of rail traffic.

scholarly journals Overview of vibroacoustic isolators used in railway tracks

2018 ◽  
Vol 219 ◽  
pp. 05001
Author(s):  
Cezary Kraśkiewicz ◽  
Wojciech Oleksiewicz ◽  
Monika Płudowska-Zagrajek ◽  
Cezary Lipko
Keyword(s):  
Structure Type ◽  
Basic Material ◽  
Track Structure ◽  
Negative Effects ◽  
Railway Traffic ◽  
Railway Tracks ◽  
Ballastless Track ◽  
Rail Vehicles ◽  
Material Characteristics ◽  
Track System

The paper presents an overview of vibroacoustic isolators used in railway tracks to reduce negative effects from railway traffic. These include single components or their assemblies, with different material characteristics and location in the track structure due to track structure type (ballasted or ballastless track system). The reduction of negative effects relates mainly to the reduction of vibration and structure-borne noise. The practical solutions for railway structures include various components that perform different functions at the same time: vibroacoustic isolation and mechanical function to ensure safe and durable use of rail track (i.e. rail fastening systems, rail supporting structures). The main goals of this paper are systematization and description of basic material characteristics of vibroacoustic isolators applied sufficiently close to the place of vibration generation during the movement of rail vehicles.

scholarly journals Finite Element Method in Assessing Strength Properties of a Railway Surface and Its Elements

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1014 ◽  
Author(s):  
Jacek Kukulski ◽  
Marianna Jacyna ◽  
Piotr Gołębiowski
Keyword(s):  
Numerical Models ◽  
Experimental Tests ◽  
Strength Properties ◽  
Railway Track ◽  
High Speeds ◽  
Rail Vehicles ◽  
Railway Infrastructure ◽  
Numerical Tools ◽  
Strength And Durability ◽  
Railway Turnout

Development of railway infrastructure at the turn of the 20th and 21st centuries, as well as the speeds of trains in passenger and freight traffic are the result of improving the structure of modern rail vehicles and railway infrastructure optimization. The structure of the railway surface, which enables high speeds and transferring ever greater loads and pressures of up to 25–30 t/vehicle axis, must meet very strict strength and durability requirements. This paper discusses mathematical and numerical tools used in simulation and experimental tests of railway surfaces, as well as its selected elements. Issues addressed in this paper concern, among others, modeling of the railway track, calculations related to its static and dynamic loading, and simulation of the technological process of selected elements of railway turnout. Selected results of the simulation tests on numerical models showing their behavior under different loads are also presented in this paper. The concept of symmetry is included in the possibility of applying the method described in the article both for testing other sections of railway lines, as well as for testing other elements in which stresses occur.

Recognition algorithm for the disengagement of cement asphalt mortar based on dynamic responses of vehicles

2018 ◽  
Vol 233 (3) ◽  
pp. 270-282 ◽  
Author(s):  
Hui Shi ◽  
Zujun Yu ◽  
Hongmei Shi ◽  
Liqiang Zhu
Keyword(s):  
Support Vector Machines ◽  
Coupled Model ◽  
Recognition Algorithm ◽  
Dynamic Responses ◽  
Support Vector ◽  
Safe Operation ◽  
Cement Asphalt Mortar ◽  
Vector Machines ◽  
Track Substructure ◽  
Asphalt Mortar

Disengagement of emulsified cement asphalt mortar will increase the dynamic action between the vehicle and the track; as a consequence, the rate of cement asphalt mortar disengagement will increase further. This is a serious threat for the safe operation of high-speed railways and the service life of rail equipment. In this study, a vertical coupled model for the vehicle–China Railway Track System II-type slab track with cement asphalt disengagement was established. The cement asphalt mortar was divided into units in order to simulate the arbitrary length of disengagement. Under different conditions, the effects of the cement asphalt mortar disengagement on the dynamic characteristics of the coupled model were analyzed. The results show that when the length of disengagement exceeds 0.65 m under the condition of horizontal complete disengagement, the dynamic responses of the system increase much sharply than the condition of horizontal partly disengagement. Because of the difficulty in identifying defects in the track substructure, a novel method was proposed to rapidly identify the cement asphalt mortar disengagement based on the dynamic responses of the coupled system and particle swarm optimization–support vector machines. The feature vectors were extracted from the acceleration of the wheelset, which were used as training samples in support vector machines. The classification results show that the recognition algorithm based on the acceleration of the wheelset and support vector machines is effective. The location of the track plate with the cement asphalt mortar disengagement at lengths of 0.65 m, 1.3 m, and 1.95 m can be identified with an acceptable accuracy. The robustness of the proposed algorithm under different vehicle speeds, track spectrums, and signal–noise ratios was verified. Recognition of defects in the track substructure using sensors mounted on in-service vehicles has the potential to provide a valuable tool for ensuring the safe operation of railways and for developing a maintenance plan.

Comparative Evaluation of Particle Movement in a Ballast Track Structure Stabilized with Biaxial and Multiaxial Geogrids

2017 ◽  
Vol 2607 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Shushu Liu ◽  
Hai Huang ◽  
Tong Qiu ◽  
Jayhyun Kwon
Keyword(s):  
Cyclic Loading ◽  
Comparative Evaluation ◽  
Vertical Displacement ◽  
Track Structure ◽  
Wireless Devices ◽  
Particle Movement ◽  
Railroad Track ◽  
Confining Effect ◽  
Ballast Track ◽  
Track Substructure

Geogrids usually are used in railroad track substructure for ballast reinforcement and stabilization over a weak subgrade. Different aperture shapes affect the confining effect on ballast particles due to the unique interlocking mechanism. To understand the effect of aperture shape on ballast particle movement and the associated interlocking mechanism, three types of ballast box tests were conducted: one without geogrid as a control, one with a layer of biaxial geogrid, and one with a layer of multiaxial geogrid. If a geogrid was included, the geogrid was placed 30 cm below the top of the ballast. A half-section of a railroad track structure consisting of two crossties, a rail, ballast, subballast, and subgrade was constructed in a ballast box. Four wireless devices known as SmartRocks were embedded under the rail seat and under the shoulder at the ballast–subballast and subballast–subgrade interfaces. Results indicate that the multiaxial geogrid significantly decreased accumulated vertical displacement in the ballast surface under cyclic loading and has the best potential for confining particle movement. The advantages of having a layer of multiaxial geogrid, including reducing particle movement, as well as decreasing vertical displacement of the ballast surface, are discussed.

Preliminary studies of vibroacoustic signal images in the context of identification of a passing rail vehicle

2018 ◽  
Vol 121 ◽  
pp. 31-40
Author(s):  
Rafał Burdzik ◽  
Paweł Słowiński ◽  
Łukasz Konieczny
Keyword(s):  
Acoustic Pressure ◽  
Technical Condition ◽  
Rail Vehicle ◽  
Rail Vehicles ◽  
Vibroacoustic Signal ◽  
Railway Infrastructure ◽  
Propagation Analysis ◽  
Conducting Research ◽  
New Research ◽  
Vibroacoustic Signals

Passing rail vehicles generate vibrations and noise. In most studies, these phenomena are analyzed in terms of impact on people, the environment and railway infrastructure. However, using the vibroacoustic methodology, generated vibration and noise signals can be treated as information carriers. The vast majority of publications in the field of vibroacoustics analyze the usability of signals to determine the technical condition of machines and systems. For many years Professor Rafał Burdzik has been conducting research in the area of vibration and noise propagation analysis in means of transport. As a result of this work, a new research hypothesis was developed as the ability to identify a vehicle or trainset based on recorded images of vibroacoustic signals. The article presents the results of preliminary tests, during which rail vibrations were recorded in three orthogonal axes and acoustic pressure signals in the axis perpendicular to the railway route.

Case study of use of falling weight deflectometer to investigate railway infrastructure constructed upon soft subgrades

2016 ◽  
Vol 53 (12) ◽  
pp. 1991-2000 ◽  
Author(s):  
Parisa Haji Abdulrazagh ◽  
Michael T. Hendry
Keyword(s):  
Dynamic Modelling ◽  
Railway Track ◽  
Falling Weight Deflectometer ◽  
Railway Infrastructure ◽  
Time Histories ◽  
Single Mass ◽  
Least Squares Curve Fitting ◽  
Track Substructure ◽  
Falling Weight

Falling weight deflectometer (FWD) testing was conducted along with embankment and subgrade sampling over 210 km (130 miles) of Canadian National Railway’s Lac La Biche Subdivision, which runs between Edmonton and Fort McMurray, as a part of a larger investigation of the line for increased axle loads. The resulting measurements were evaluated for their ability to identify soft subgrades. Two analyses were conducted to this end. First, the statistical distribution of peak deflections recorded by the FWD was investigated for different types of subgrade material. Second, the properties of track substructure were studied by characterizing the deflection time histories using a dynamic model of a single mass on a viscoelastic foundation and least-squares curve fitting. Four characteristic types of deflection time histories were identified for differing substructure conditions. Simplified dynamic modelling of railway track substructure showed that where relatively thick embankment exists over subgrade, the response of track is overdamped behavior.

Track Substructure Design Methodology and Data

2010 ◽  
Author(s):  
Theodore R. Sussmann ◽  
James P. Hyslip
Keyword(s):  
Material Properties ◽  
High Speed ◽  
Progressive Failure ◽  
Failure Process ◽  
Structure Design ◽  
Design Methods ◽  
Railway Track ◽  
Track Structure ◽  
Design Data ◽  
Track Substructure

Track substructure design is an often overlooked step in the design of railroad track. The lack of consideration for the substructure when designing track results in greater maintenance demands due to inadequate track substructure performance. Railway track is a stable structure with a progressive failure process that allows track engineers to manage the degradation of the track through maintenance. However, increasing demands for track availability from high traffic volumes require that track maintenance be minimized while ensuring safety. Additionally, developing high speed rail and intercity passenger rail on existing corridors necessitates higher levels of substructure performance due to tighter track roughness tolerances. Reduction in maintenance needs can be achieved by ensuring that new construction and rehabilitation projects be designed to provide a stable track structure throughout the design life. Lack of readily available data for substructure materials is a drawback to the use of track design methods. This paper provides a summary of several available substructure track design methods along with the required data for design. The track design data is related to track measurements that could be used to determine much of the information necessary for design of track rehabilitation. Track load-deflection data could be used to develop much of the needed design data while ground penetrating radar could support delineation of similar track segments. Benefits of track structure design include knowledge of expected life, reduced maintenance, material properties for quality control, and development of material properties that could permit application of performance based contract specifications.

scholarly journals Study of the possibility of using transmission in the lte system on a selected railway line for the purpose of running railway traffic

2021 ◽  
Vol 57 (1) ◽  
pp. 91-101
Author(s):  
Marcin Chrzan
Keyword(s):  
Control Systems ◽  
Traffic Control ◽  
Research Work ◽  
Rolling Stock ◽  
The European Union ◽  
Radio Communication ◽  
Railway Line ◽  
Railway Traffic ◽  
Railway Infrastructure ◽  
Rail Traffic

The railway and the Rail Traffic Control Systems installed on it in Poland have recently experienced rapid technologi-cal development. This is undoubtedly due to the funds that Poland receives from the European Union for the moderni-zation of railway infrastructure. The development of modern railway infrastructure means not only stations, modern rolling stock, but also safe and reliable train control systems based on the latest telecommunications and information technologies. For a longer time, radio communication based on the GSM-R (GSM for Railways) standard is being introduced on PKP. For this purpose, dedicated infrastructure is being built in order to use this technology for railway traffic. This is associated with huge investment costs. Since the beginning of its existence, research has been conducted worldwide on the use of LTE (Long Term Evolution) technology for conducting railway traffic. For economic and technological reasons, it is necessary to study other possibilities of using modern telecommunications infrastructure not yet dedicated to railway tasks in these open networks. The article will present research on the use of open radio communication network based on LTE standard for rail traffic and passenger comfort. It will discuss the research method and selected results of measurements made on railway line no. 4. The choice of this railway line was dictated by two factors. The first one resulted from the maximum train speed, the second one is the variety of rolling stock used on this line (compartmental and non-compartmental wagons). The part of research concerning collection of measurement material was performed within the framework of completed research work PBS3/A6/29/2015. As a result of conducted in-depth literature analysis as well as performed measurements and calculations, it allowed to develop a model and software for simulating system operation in real conditions. This system allows to send railway telegrams on appropriate safety level defined in standardization documents. The research proved the possibility of using an open system in the LTE standard for the transmission of signals for railway traffic control and passengers while maintaining an appropriate level of safety. The only limitations which were indicated by the tests are improper radio interface coverage of railway lines. Appropriate planning of radio coverage of railway areas by radio communi-cation operators (so far ignored) with proper cooperation of infrastructure manager can lead to launching efficient communication system without necessity to build specialized infrastructure for railway.

scholarly journals Evaluation of tramway overhead line system in city of Osijek

2018 ◽  
Vol 180 ◽  
pp. 06003
Author(s):  
Ivo Haladin ◽  
Stjepan Lakušić ◽  
Ivan Duvnjak
Keyword(s):  
Optimal Level ◽  
Rolling Stock ◽  
Track Structure ◽  
Overhead Line ◽  
Transit System ◽  
Line System ◽  
Railway Infrastructure ◽  
Site Evaluation ◽  
Gis Environment ◽  
Measurement And Evaluation

Overhead line system is a vital element of any electrified railway infrastructure. Its performance reflects to all vital parameters such as traction, reliability, availability and safety of railway infrastructure. Operator GPP Osijek runs a 27.5 km long tramway network which plays a key role in transit system of the city of Osijek, Croatia. In 2016 GPP Osijek applied to a tender for acquisition of new rolling stock with 85% EU investment. Mayor requirement prior to rolling stock acquisition was to document, analyse and upgrade current infrastructure (including track structure, electric substations and catenary) to an optimal level. Task of measurement and evaluation of tram track structure and catenary has been appointed to University of Zagreb Faculty of Civil Engineering. Overhead line analysis comprised from several measuring procedures, including supporting columns evaluation, catenary stagger, height, shocks and wear. Such extensive analysis included GPS positioning and on-site evaluation of 1214 supporting columns of overhead line, as well as overhead line measurements using an instrumented tram vehicle on 18 km of track. For conducting overhead catenary wire measurements, a tram pantograph has been fitted with equipment for measuring catenary height, accelerometers for shock measurement, camera, ruler and GPS for stagger measurement. Catenary wire wear was checked manually from catenary inspection vehicle. To conduct measurements, power had to be switched off on all electric substation along the route and tram vehicle had to be towed by a catenary inspection vehicle. All the data has been analysed and presented to end user in a user-friendly and intuitive GIS environment capable of further updates and detailed analyses. Evaluation of overhead line based on direct measurement results pointed out all the defects and weak spots on the system. It resulted in a series of recommendations for reconstruction and upgrade of the catenary system to fit the need of existing state and further development of tramway network.

scholarly journals The approximate modelling of a “rail vehicle-railway track- substructure” system

2017 ◽  
Vol 66 (2) ◽  
pp. 107-121
Author(s):  
Tomasz Lewandrowski ◽  
Paweł Muzolf ◽  
Włodzimierz Idczak
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Moving Load ◽  
Railway Track ◽  
Railway Vehicle ◽  
Time Step ◽  
Railway Infrastructure ◽  
Space Step ◽  
Track Substructure

A system “railway vehicle–railway track–substructure” was analysed. Rails were modelled as the Bernoulii-Euler beams on an elastic foundation. Two load cases were considered a) static load from the train to the railway track, b) dynamic load from the train moving with the constant velocity. As a result, the fourth-order differential equation was obtained. Both, material data and operating parameters were determined by components of the equation. To solve this equation, the finite difference method was used. This method was described considering such matters as space step, time step, discretization, and moving load modelling. Evaluation of usefulness of a selected method in modelling a railway infrastructure was the purpose of the authors. The obtained results were compared with results received by analytical way. The presented, simplified model: railway vehicle–infrastructure–substructure after appropriative validation will be used later on to analyse various technical solutions and materials in designing railway constructions. Keywords: numerical methods, finite difference method, railway infrastructure, dynamic impact factor

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