FOSA Installation Considerations
Distributed fiber optic sensing techniques, such as DAS, DSS or DTS are powerful tools for the monitoring of long, linear assets. Consequently, these approaches fit perfectly with specific requirements of the railroad industry, where they can fulfill objectives in various areas:
• Tracking the position, direction, speed & length of trains
• Monitoring rolling stock defects (flat / defective wheels and defective bearings)
• Monitoring rail defects (rail breaks, rail buckling or bad welds / joins)
• Detecting trackside activity (work crews, trespassers, cable tampering)
• Detecting Rockfall and landslide events in the vicinity of the track
In each of these applications, distributed fiber optic sensing offers clear benefit in the ability to cover a wide area from a central monitoring point, and can often achieve this by repurposing spare fibers in the existing railroad communication network.
Optimum performance for any particular sensing objective is dependent on cable type, installation method, cable position and the environmental conditions of the site. This applies to both existing cables and those installed specifically for distributed fiber optic sensing.
This document provides guidance on best practice for the selection and installation of cables for fiber optic sensing in the railroad domain. In general, the most prevalent sensing technology for railroad applications is Distributed Acoustic Sensing (DAS) which monitors vibrations transmitted to the fiber from nearby energy sources – such as moving trains, people or vehicles.