The invention discloses a 
foreign matter limit invasion 
monitoring system based on 
fiber Bragg gratings. The 
foreign matter limit invasion 
monitoring system based on the 
fiber Bragg gratings comprises a 
foreign matter limit invasion 
monitoring system, a monitoring 
host machine system and a foreign matter limit invasion 
sensing system. The foreign matter limit invasion 
sensing system is used for sensing foreign matter limit invasion information and transmitting the foreign matter limit invasion information to the foreign matter limit invasion monitoring 
system, after the foreign matter limit invasion monitoring 
system receives the foreign matter limit invasion information, the foreign matter limit invasion information is processed and converted into a sensing 
signal, the sensing 
signal is transmitted to the monitoring 
host machine system, and the monitoring 
host machine system stores and processes the foreign matter limit invasion information. According to the foreign matter limit invasion monitoring system based on the 
fiber Bragg gratings, a single-mesh double-optical network mode is adopted, a fault point can be accurately positioned, rapid positioning of faults is achieved, 
usability, safety and reliability are improved, and repairing and maintaining cost are saved. The foreign matter limit invasion monitoring system based on the fiber Bragg gratings is capable of achieving uninterrupted monitoring and effectively preventing accidents of derailing of a 
train and the like from happening before foreign matter limit invasion is beyond a safety range.