The railroad network requires constant inspection of rail integrity. Early defect detection is of utmost importance to maintain safety and reduce costs. This work proposes a new non-destructive probe configuration to be used in an inspection method based in eddy currents, which optimizes the detection of defects in a conductive material moving relative to the probe. This approach uses velocity induced eddy currents where the motion of a permanent magnetic field induces currents on the surface of the metal, and it is not restricted by the inspection speed limitations of more traditional methods. A differential sensing coil is used as a magnetic sensor that can detect current flow perturbations caused by the presence of defects.