Smart Railway Traffic Monitoring Using Fiber Bragg Grating Strain Gauges

• Main Authors: Boelen, K. (Author), Caucheteur, C. (Author), Finet, C. (Author), Guyot, C. (Author), Kinet, D. (Author), Kouroussis, G. (Author), Van Esbeen, B. (Author), Vandebrouck, R. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: fiber bragg gratings; railway; safety; sensors
• Online Access: View Fulltext in Publisher

 There is today ample evidence that fiber Bragg gratings (FBGs) distributed along a railway track can provide robust axle counting and bring numerous assets compared to competing technologies in this practical environment. This work brings two relevant originalities with respect to the state-of-the-art solutions. First, a study of the strain distribution in the rail cross-section is performed to determine the sensitivity according to the charge and the position on the rail. Secondly, the technology is deployed along the rail track as a smart object where the sensor head is composed of four FBG wavelength-division-multiplexed in a single telecommunication-grade optical fiber and interrogated by a miniaturized read-out device. Two FBGs ensure the detection of the train direction and another two bring the required redundancy to reach a safety integrity level (SIL) 4. The read-out unit has been specifically developed for the application and contains a vertical-cavity surface-emitting laser (VCSEL) and a photodiode driven by a high-speed microprocessor unit that processes the data and communicates the useful information, i.e., the number of axles. On-field tests confirm that the proposed approach makes the installation process easier while it democratizes the technology. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.