Abstract: At least one powered disc is suspended from a locomotive and applied to a rail surface for treating the rail surface ahead of driven locomotive wheels to increase adhesion between the driven wheels and the rail surface. Torque applied to the disc varies the rate of rotation of the disc away from that of a freely-rotating disc so that a significant level of creep may be maintained between the disc and the rail surface with substantially no angle of attack between the disc and the longitudinal axis of the rail. The torque may be generated through a second disc contacting the rail and coupled to the first disc with the first and second discs rotating with differing rates of rotation, or may be generated through a passive or active actuator coupled directly to the disc. The amount of creep between the disc and the rail surface and the direction of the creep may be varied in accordance with the level of contamination of the rail and the disc may be disengaged from the rail when cleaning is not required.