CTI provides on-site monitoring and measurement related rail transit structure deformation measurement services. Rail transit deformation includes two forms: track structure deformation and tunnel structure deformation. The main reason for the deformation of the track structure is the long-term repeated effects of the train load on the track, causing geometric deviation of the track, which in turn affects the smoothness and smoothness of the track; in addition to the effect of the train load, the unloading, loading, and loading of the construction around the tunnel are also It will cause uneven settlement of the track bed, which will also affect the flatness and smoothness of the track.