scholarly journals Optical Fibres for Condition Monitoring of Railway Infrastructure—Encouraging Data Source or Errant Effort?

2020 ◽  
Vol 10 (17) ◽  
pp. 6016 ◽  
Author(s):  
Ivan Vidovic ◽  
Stefan Marschnig
Keyword(s):  
Rayleigh Scattering ◽  
Acoustic Vibration ◽  
Optical Fibres ◽  
Maintenance Planning ◽  
Root Cause ◽  
Railway Tracks ◽  
Railway Infrastructure ◽  
Vibration Sensing ◽  
Data Source ◽  
Asset Data

The condition of railway infrastructure is currently assessed by track recording cars, wayside equipment, onboard monitoring techniques and visual inspections. These data sources deliver valuable information for infrastructure managers on the asset’s condition but are mostly carried out in time-based intervals. This paper examines the potential of fibre optic cables, which are already installed in cable troughs alongside railway tracks, to monitor railway infrastructure conditions. The sensing technique, known as distributed acoustic/vibration sensing (DAS/DVS), relies on the effect of Rayleigh scattering and transforms the optical fibre into an array of “virtual microphones” in the thousands. This sensing method has the ability to be used over long distances and thus provide information about the events taking place in the proximity of the monitored asset in real-time. This study outlines the potential of DAS for the identification of different track conditions and isolated track defects. The results are linked to asset data of the infrastructure manager to identify the root cause of the detected signal anomalies and pattern. A methodology such as this allows for condition-based and component-specific maintenance planning and execution and avoids the installation of additional sensors. DAS can pave the way toward a permanent and holistic assessment of railway tracks.

Sensitivity of high Rayleigh scattering fiber in acoustic/vibration sensing using phase-OTDR

2018 ◽  
Author(s):  
Oleg V. Butov ◽  
Yuri K. Chamorovskii ◽  
Konstantin M. Golant ◽  
Andrei A. Fotiadi ◽  
Johan Jason ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Acoustic Vibration ◽  
Vibration Sensing

scholarly journals Hollow core optical fibres with comparable attenuation to silica fibres between 600 and 1100 nm

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hesham Sakr ◽  
Yong Chen ◽  
Gregory T. Jasion ◽  
Thomas D. Bradley ◽  
John R. Hayes ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Density Fluctuations ◽  
Power Delivery ◽  
Optical Data ◽  
Optical Fibres ◽  
Hollow Core ◽  
Quantum Communications ◽  
Scattering Loss ◽  
Air Core ◽  
Solid Glass

AbstractFor over 50 years, pure or doped silica glass optical fibres have been an unrivalled platform for the transmission of laser light and optical data at wavelengths from the visible to the near infra-red. Rayleigh scattering, arising from frozen-in density fluctuations in the glass, fundamentally limits the minimum attenuation of these fibres and hence restricts their application, especially at shorter wavelengths. Guiding light in hollow (air) core fibres offers a potential way to overcome this insurmountable attenuation limit set by the glass’s scattering, but requires reduction of all the other loss-inducing mechanisms. Here we report hollow core fibres, of nested antiresonant design, with losses comparable or lower than achievable in solid glass fibres around technologically relevant wavelengths of 660, 850, and 1060 nm. Their lower than Rayleigh scattering loss in an air-guiding structure offers the potential for advances in quantum communications, data transmission, and laser power delivery.

scholarly journals Review of Track Gauge for Trans-Sumatera Railway Revitalization and Development

2020 ◽  
Vol 22 (1) ◽  
pp. 25-36
Author(s):  
Soemino Eko Saputro ◽  
Prasadja Ricardianto ◽  
Haniva Mulyani ◽  
Primadi Candra Susanto
Keyword(s):  
Performance Indicators ◽  
Decision Makers ◽  
Construction Equipment ◽  
International Standard ◽  
Railway Tracks ◽  
World Today ◽  
Railway Infrastructure ◽  
The World ◽  
The Future

The aim of this research is to comprehend in details how revitalization and development of railway infrastructure on the Trans-Sumatera line in Sumatera Island. The main problem in this research is that the use of railways in Sumatera Island is neither sustainable nor in all provinces. This research is both meta-analytical, by exploring the existing journals, and factual as a phenomenon in the utilization of spoor width that happens in the world today. It is completed by parameter or performance indicators as for benchmarking with other countries. From the result of this research, the data shows that almost 60 percent of existing railway tracks around the world have been installed with standard gauge of 1,435 mm and have been international standard. The benefit of this study is that the leaders or decision makers can take it into account to support the future transportation in Sumatera Island which must be oriented to bigger, faster, safer, cleaner, cheaper, affordable, and leisure. To keep exploiting the existing railway or track can be done by developing construction equipment of track gauge adjuster to change the wheel gauge from 1,435 mm to 1,067 mm. Subsequently re-gauging is done in stages, changing the track gauge from narrow gauge of 1,067 mm to standard gauge of 1,435 mm.

scholarly journals Baseline Model to Increase Railway Infrastructure Capacity on a Single-Track Section: a Case Study

2017 ◽  
Vol 8 (2) ◽  
pp. 69-80 ◽  
Author(s):  
Stefano Ricci ◽  
Vladimír Ľupták ◽  
Mária Chovancová
Keyword(s):  
Regional Level ◽  
Single Track ◽  
Passenger Transport ◽  
Baseline Model ◽  
Railway Tracks ◽  
Railway Infrastructure ◽  
Transportation Capacity ◽  
National Perspective

Abstract Providing the railway infrastructure is a prerequisite for achieving the quality of public passenger transport, not only from a national perspective but also within a regional level. Based on transportation capacity knowledge, railway tracks capacity and headway can be determined. Subsequently, it is possible to examine the railway sections capacity and select a measure in order to increase this capacity.

Noise Analysis of φ-OTDR Vibration Sensing System

2014 ◽  
Vol 687-691 ◽  
pp. 459-462
Author(s):  
Li Ma ◽  
Yong Qian Li
Keyword(s):  
Rayleigh Scattering ◽  
Noise Analysis ◽  
Vibration Sensor ◽  
Noise Amplitude ◽  
Matlab Simulation ◽  
High Noise ◽  
Sensing System ◽  
Effective Suppression ◽  
Vibration Sensing ◽  
Suppression Method

The interference principle of backscattering light in the optical fiber is analyzed theoretically and the sensing mechanism of φ-OTDR vibration sensor system is introduced briefly in this paper. The trace of backward Rayleigh scattering is obtained by MATLAB simulation, and it is compared to the scattering curve by experiment. The result shows that noise is inevitable in the experiment, and the desired signal is difficult to be detected for the high noise amplitude. For obtaining high SNR in the experiment, the compositions and causes of the noise is introduced and the effective suppression method are put forward.

Strain and crack analysis within concrete members using distributed fibre optic sensors

2018 ◽  
Vol 18 (5-6) ◽  
pp. 1510-1526 ◽  
Author(s):  
Rafał Sieńko ◽  
Mariusz Zych ◽  
Łukasz Bednarski ◽  
Tomasz Howiacki
Keyword(s):  
Reinforced Concrete ◽  
Optical Fibre ◽  
Structural Damage ◽  
Rayleigh Scattering ◽  
Measurement Data ◽  
Sensor Technology ◽  
Optical Fibres ◽  
Structural Behaviour ◽  
Fibre Optics ◽  
Concrete Members

This article presents laboratory tests, with the purpose being to verify the suitability of standard optical fibres in a tight jacket for advanced strain analysis within concrete members. An optical reflectometer was used to enable the optical signal to be processed on the basis of the Rayleigh scattering phenomenon, so that strains and/or temperature changes were determined along the length of the measuring fibre. The measurements were carried out continuously in a geometrical sense (distributed measurements), with a spatial resolution starting from as fine as 5 mm. The arrangement of optical fibres inside the heterogeneous concrete medium and on its surface allowed for the identification and detailed analysis of local phenomena such as cracks. Remote and early location of structural damage with an estimation of its scale provides new opportunities for the monitoring of the structural health of reinforced concrete structures, facilitating the interpretation of its behaviour as well as failure risk management based on comprehensive and reliable measurement data. If traditional spot techniques are used, this approach is not possible. The aim of the initial studies was to analyse the strain distributions over compressed and tensioned measurement sections located on the surface of a cylindrical specimen of concrete. In the tests which followed, the reinforced concrete rod was eccentrically tensioned with fibre optics installed inside. Qualitative and quantitative verification of crack widths was made, with a narrow range up to 0.05 mm and a wider one to 0.30 mm. The results of the studies show very good accuracy of optical fibre sensor technology as a reference technique during the analysis of microcracks and narrow cracks, and moderate accuracy in the case of wider cracks. Despite using optical fibres in a tight jacket which mediates in strain transfer, the results obtained can be very suitable for the assessment of the structural condition of the member under consideration. It is also worth noting that the tests conducted indicate the effectiveness of distributed optical fibre technology for the analysis of concrete homogeneity and its structural behaviour within compressed areas, as it is possible to calculate strains over measuring bases that start from lengths as short as 5 mm.

Rayleigh Scattering From Multimode Optical Fibres At Very High Temperatures

1990 ◽  
Author(s):  
D. J. Booth ◽  
S. F. Collins ◽  
A. Shelamoff ◽  
J. C. Scott
Keyword(s):  
High Temperatures ◽  
Rayleigh Scattering ◽  
Optical Fibres ◽  
Very High

scholarly journals Historical Development and Applications of Unconventional Structure of Railway Superstructure of the Railway Infrastructure of the Slovak Republic

2014 ◽  
Vol 10 (1) ◽  
pp. 79-94 ◽  
Author(s):  
Libor Ižvolt ◽  
Michal Šmalo
Keyword(s):  
Historical Development ◽  
Slovak Republic ◽  
Slab Track ◽  
The Third ◽  
Railway Tracks ◽  
Railway Infrastructure

Abstract In the first part, the paper deals with the origin and reasons to construct an unconventional type of the structure of railway superstructure, which is referred to as a slab track, it is shortly characterized by its development and the possible application of the railway tracks. The second part of the paper deals with the historical development of unconventional structure of railway superstructure in the Slovak Republic, characteristics of the developed and tested structures, and then in the third part of this paper, there are characterized specific structures of slab track applied in the ongoing modernization of the railway infrastructure in the Slovak Republic

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