Rail car positioning system and method

The invention discloses a rail car positioning system and method, and the system comprises shield segments, each shield segment is provided with a segment number, a circular seam is formed between any adjacent shield segments, and the shield segments and a rail are within a preset distance range; the camera is arranged on the rail car and used for acquiring shield segment images; the data processing module is used for determining a segment number and a circular seam straight line according to the shield segment image, and positioning the rail car based on the segment number and the circular seam straight line; on one hand, as the duct piece number corresponds to the position, the positioning of the rail car can be determined through the duct piece number and the circular seam straight line; on the other hand, in the process of obtaining the shield segment image and carrying out data processing on the shield segment image, external information exchange is not depended on, and the environment where the rail car