scholarly journals Quantification of the Mechanized Ballast Cleaning Process Efficiency Using GPR Technology

2021 ◽  
Vol 13 (8) ◽  
pp. 1510
Author(s):  
Anna Borkovcová ◽  
Vladislav Borecký ◽  
Salih Serkan Artagan ◽  
Filip Ševčík
Keyword(s):  
Time Domain Analysis ◽  
Process Efficiency ◽  
Railway Track ◽  
Relative Dielectric Permittivity ◽  
Cleaning Process ◽  
Railway Ballast ◽  
Railway Infrastructure ◽  
Cleaning Intervention ◽  
Ground Penetrating

Ground Penetrating Radar (GPR) has been used recently for diagnostics of the railway infrastructure, particularly the ballast layer. To overcome ballast fouling, mechanized ballast cleaning process, which increases track occupancy time and cost, is usually used. Hence it is of crucial significance to identify at which stage of track ballast life cycle, and level of fouling, ballast cleaning should be initiated. In the present study, a series of in situ GPR surveys on selected railway track sections in Czechia was performed to obtain railway granite ballast relative dielectric permittivity (RDP) values in several phases of railway track lifecycle. GPR data were collected in the form of B-scan, and time-domain analysis was used for post-processing. The results indicate (i) change of railway ballast RDP in time (long term); (ii) a dependency of ballast fouling level on RDP; and (iii) the RDP change during the ballast cleaning process, thus its efficiency. This research aimed to provide new perspectives into the decision-making process in initiating the mechanized ballast cleaning intervention based on the GPR-measured data.

scholarly journals Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways

2020 ◽  
Vol 28 (3) ◽  
pp. 213-231
Author(s):  
Wanming Zhai ◽  
Kaiyun Wang ◽  
Zhaowei Chen ◽  
Shengyang Zhu ◽  
Chengbiao Cai ◽  
...  
Keyword(s):  
High Speed ◽  
Mechanical Performance ◽  
Full Scale ◽  
Functional Test ◽  
Railway Track ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Railway Infrastructure ◽  
Test Platform

Abstract Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure, a full-scale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper, and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples. Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways, namely the CRTS I, the CRTS II and the CRTS III ballastless tracks, the double-block ballastless track and the ballasted track, the test platform is established strictly according to the construction standard of Chinese high-speed railways. Three kinds of effective loading methods are employed, including the real bogie loading, multi-point loading and the impact loading. Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement, acceleration, pressure, structural strain and deformation, etc. Utilizing this test platform, both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated, being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways. As examples, three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways. Some interesting phenomena and meaningful results are captured by the developed test platform, which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure.

scholarly journals Development of fragility curves for railway ballast and embankment scour due to overtopping flood flow

2016 ◽  
Author(s):  
Ryota Tsubaki ◽  
Koji Ichii ◽  
Jeremy D. Bricker ◽  
Yoshihisa Kawahara
Keyword(s):  
Spatial Distribution ◽  
Failure Probability ◽  
Fragility Curves ◽  
Railway Track ◽  
Single Track ◽  
Hydraulic Analysis ◽  
Railway Ballast ◽  
Log Normal ◽  
Flood Flow

Abstract. Fragility curves evaluating risk of railway track ballast and embankment fill scour were developed. To develop fragility curves, two well-documented single-track railway washouts during two recent floods in Japan were investigated. Type of damage to the railway was categorized into no damage, ballast scour, and embankment scour, in order of damage severity. Railway overtopping surcharge for each event was estimated via hydrologic and hydraulic analysis. Normal and log-normal fragility curves were developed based on failure probability derived from field records. A combined ballast and embankment scour model was validated by comparing the spatial distribution of railway scour with the field damage record.

scholarly journals Micro-mechanical investigation of railway ballast behavior under cyclic loading in a box test using DEM: effects of elastic layers and ballast types

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Early Stage ◽  
Damage Model ◽  
Simulation Models ◽  
Railway Track ◽  
Maintenance Cost ◽  
Particle Movement ◽  
Railway Ballast ◽  
Elastic Layers ◽  
The Impact

Abstract Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers are increasingly used for improving ballasted tracks. In order to better understand the effects of elastic layers, physical understanding at the ballast particle level is crucial. Here, discrete element method (DEM) is used to investigate the effects of elastic layers – under sleeper pad ($$\text {USP}$$USP) at the sleeper/ballast interface and under ballast mat ($$\text {UBM}$$UBM) at the ballast/bottom interface – on micro-mechanical behavior of railway ballast. In the DEM model, the Conical Damage Model (CDM) is used for contact modelling. This model was calibrated in Suhr et al. (Granul Matter 20(4):70, 2018) for the simulation of two different types of ballast. The CDM model accounts for particle edge breakage, which is an important phenomenon especially at the early stage of a tamping cycle, and thus essential, when investigating the impact of elastic layers in the ballast bed. DEM results confirm that during cyclic loading, $$\text {USP}$$USP reduces the edge breakage at the sleeper/ballast interface. On the other hand, $$\text {UBM}$$UBM shows higher particle movement throughout the ballast bed. Both the edge breakage and particle movement in the ballast bed are found to influence the sleeper settlement. Micro-mechanical investigations show that the force chain in deeper regions of the ballast bed is less affected by $$\text {USP}$$USP for the two types of ballast. Conversely, dense lateral forces near to the box bottom were seen with $$\text {UBM}$$UBM. The findings are in good (qualitative) agreement with the experimental observations. Thus, DEM simulations can aid to better understand the micro-macro phenomena for railway ballast. This can help to improve the track components and track design based on simulation models taking into account the physical behavior of ballast. Graphical Abstract

scholarly journals Building Capabilities Through Democratic Dialogues

Design Issues ◽  
2018 ◽  
Vol 34 (4) ◽  
pp. 80-95 ◽  
Author(s):  
Liesbeth Huybrechts ◽  
Katrien Dreessen ◽  
Ben Hagenaars
Keyword(s):  
Design Process ◽  
Participatory Design ◽  
Design Approach ◽  
Railway Track ◽  
Alternative Futures ◽  
Design Processes ◽  
Self Organized ◽  
Complex Design ◽  
Developing Strategies

Designers are increasingly involved in designing alternative futures for their cities, together with or self-organized by citizens. This article discusses the fact that (groups of) citizens often lack the support or negotiation power to engage in or sustain parts of these complex design processes. Therefore the “capabilities” of these citizens to collectively visualize, reflect, and act in these processes need to be strengthened. We discuss our design process of “democratic dialogues” in Traces of Coal—a project that researches and designs together with the citizens an alternative spatial future for a partially obsolete railway track in the Belgian city of Genk. This process is framed in a Participatory Design approach and, more specifically, in what is called “infrastructuring,” or the process of developing strategies for the long-term involvement of participants in the design of spaces, objects, or systems. Based on this process, we developed a typology of how the three clusters of capabilities (i.e., visualize, reflect, and act) are supported through democratic dialogues in PD processes, linking them to the roles of the designer, activities, and used tools.

scholarly journals Verification of GNSS Measurements of the Railway Track Using Standard Techniques for Determining Coordinates

2020 ◽  
Vol 12 (18) ◽  
pp. 2874 ◽  
Author(s):  
Cezary Specht ◽  
Andrzej Wilk ◽  
Wladyslaw Koc ◽  
Krzysztof Karwowski ◽  
Paweł Dąbrowski ◽  
...  
Keyword(s):  
Measuring System ◽  
Railway Track ◽  
Satellite Measurements ◽  
Railway Line ◽  
University Of Technology ◽  
Railway Infrastructure ◽  
Spatial System ◽  
Mobile Satellite ◽  
Gnss Measurements ◽  
Geometric Layout

The problem of the reproduction of the railway geometric layout in the global spatial system is currently solved in the form of measurements that use geodetic railway networks and also, in recent years, efficient methods of mobile positioning (mainly satellite and inert). The team of authors from the Gdańsk University of Technology and the Maritime University in Gdynia as part of the research project InnoSatTrack is looking for effective and efficient methods for the inventory of railway lines. The research is part of a wider investigation BRIK (Research and Development in Railway Infrastructure, in polish: Badania i Rozwój w Infrastrukturze Kolejowej). This paper presents a comparative analysis of the problem of the reproduction of the trajectory of the measuring system using tacheometry, satellite measurements made using a measurement trolley, and mobile satellite measurements. Algorithms enabling the assessment of the compliance of satellite measurements with classic tacheometric measurements were presented. To this end, the authors held measurement sessions using modern geodetic instruments and satellite navigation on a section of the railway line. The results of the measurements indicate the convergence of the level of accuracy achieved by different measuring techniques.

scholarly journals Railway Ballast Monitoring by Gpr: A Test Site Investigation

2019 ◽  
Vol 11 (20) ◽  
pp. 2381 ◽  
Author(s):  
Bianchini Ciampoli ◽  
Calvi ◽  
D’Amico
Keyword(s):  
Asset Management ◽  
Construction Materials ◽  
Site Investigation ◽  
Horn Antenna ◽  
Test Site ◽  
Electromagnetic Response ◽  
Actual Condition ◽  
Railway Ballast ◽  
Set Up ◽  
Ground Penetrating

Effective maintenance of railways requires a comprehensive assessment of the actual condition of the construction materials involved. In this regard, Ground-Penetrating Radar (GPR) stands as a viable alternative to the invasive and time-consuming traditional techniques for the inspection of these infrastructures. This work reports the experimental activities carried out on a test-site area within a railway depot in Rome, Italy. To this purpose, a 30 m-long railway section was divided into 10 sub-sections reproducing different various physical and structural conditions of the track-bed. In more detail, combinations of varying scenarios of fragmentation and fouling of the ballast were reproduced. The set-up was then investigated using different multi-frequency GPR horn antenna systems. The effects of the different physical conditions of ballast on the electromagnetic response of the material were analysed for each scenario using time- and frequency-domain signal processing techniques. Parallel to this, modelling was provided to estimate fouling content. Interpretation of results has proven the viability of the GPR method in detecting signs of decay at the network level, thereby proving this technique to be worthy of implementation in asset management systems.

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