In this paper, an open flexure hinge lever structure is combined with metallized fiber Bragg grating (FBG) to create an FBG pressure sensor for dynamic track weighing. First, metallized FBG is adopted so that it could be easily welded to the flexible hinge bracket. The FBG demodulator with a high response frequency is then used to read experimental data at rapid speed. Finally, electromagnetic interference problem in the testing system is fundamentally solved using the FBG pressure sensor, and the hinge connection is employed to replace the rigid connection to improve the sensor's sensitivity. The experimental results show that the sensor's pressure sensitivity can reach 60.8 pm/t and the strain sensitivity can reach 5.653 pm/με.