Abstract:The close contact between the wheel and rail makes the irregularities of the head of the rail, and the traditional rail detection method mainly measures the vertical wear and horizontal wear of the rail, and can not fully reflect the contour information of the rail cross section. Based on the Gocator visual sensor acquisition and stitching the complete rail head contour data and the standard rail track profile curve, the calculation of the residual area of the head, the head 45 ° angle wear and the head angle parameters of the calculation method. In this method, the discrete points data obtained by the sensor splicing are used to optimize the sub-cubic fitting method. The polynomial is obtained by integrating the polynomials in turn. The intersection of the straight line and the measurement profile is calculated by the wear of the 45 ° angle ; calculate the head of the arc at the intersection of tangent slope to get the head angle. The experimental data show that the parameters with the same cross section are small, the precision is high and the calculation speed is fast. The effective measurement of these parameters can provide guidance for the automatic grinding and maintenance of rail.