OBHATMS Principle

How does OBHATMS work?

  • This system deploys optical fiber over the axle boxes.
  • When light from source passes along the optical fiber, the intensity of reflected light varies with temperature.
  • This variation is captured continuously and calibrated to record temperature data.
  • Based on the configured benchmark, the alerts are generated.
  • Alerts are communicated to loco pilot and maintenance teams through HMI connected to cloud server.

The above picture shows various hardware components that are used in the OBHATMS system and their inter-connection.

Optical Time Domain Reflectometry (OTDR)

  • Provides location of hot axle.
  • As light travels through the optical fiber, a portion is scattered back toward the source.
  • By analyzing the time it takes for the light to return, the exact location and the length of the overheated area is identified.
OTDR 01
OTDR 02

Raman Scattering

  • Provides amount of heat or temperature.
  • When light interacts with molecular vibrations in the material, its wavelength shifts.
  • By analyzing the ratio of Stokes to Anti-Stokes scattering, OBHATMS can accurately measure the temperature of the axle with high precision.