Patent ID: 8861973

Claim:
A monitoring system for a train moving on a pair of railway tracks, comprising: an optical fiber, wherein a first part of the fiber is attachable to one of the pair of railway tracks, the first part of the fiber including a first Bragg grating that is pre-strained in a direction at least substantially parallel to said one track; an optical signal emitter connected to a first end of the fiber configured to emit an optical signal into the fiber, wherein the first Bragg grating generates at least a first altered optical signal that is a reflected optical signal, and which contains information relating to a variance of a grating period of the first Bragg grating, wherein the grating period is variable in correspondence to a change in a tensile strain on the first Bragg grating; an optical signal analyzer connected to the first end of the fiber configured to receive and to analyze the first altered optical signal so as to ascertain the variance of said tensile strain of the first Bragg grating based upon the information contained in the first altered optical signal; and a processor configured to receive an analysis of the first altered optical signal from the optical signal analyzer and to correlate the variance of said grating period of the first Bragg grating with a corresponding variance of said tensile strain of the first Bragg grating; and to further correlate the variance of said tensile strain of the first Bragg grating with a characteristic of the train moving on the pair of tracks.