The main condition monitoring of the line: track (orbit temperature and orbital vibration) and roadbed of railway operation along the line, mountain near the line (roadbed settlement and landslide)

Track temperature: The temperature change reflects the stress. The existence of the temperature gradient field causes micro-cracks in the rail. The change of thermal expansion and contraction causes unnecessary stress on the fixed joint of the rail.

Rail Vibration: Rail dynamic load increases with the increase of load, impact vibration and rail structure damage aggravate, wave wear occurs, which is directly related to train derailment coefficient.

Roadbed and slope: The road conditions through which the railway passes are complex, and natural disasters are prone to occur. By traditional labor, the efficiency is low, and the working environment is difficult; point sensing can not achieve full line coverage, obviously can not meet the actual needs.

Distributed optical fiber sensor system is sensitive and quantifiable to temperature, strain and vibration to realize distributed monitoring of track and along-line conditions.