An adhesion control system for a locomotive is provided for achieving and maintaining a maximum adhesion value. The adhesion control system includes a means for determining from an appropriate adhesion-creep curve an ideal creep rate that must be achieved and maintained in order to achieve and maintain a maximum adhesion value, a means for estimating an actual creep rate through the measurement or estimation of motor or wheel acceleration and locomotive acceleration, a means for selecting a creep rate set point based on a comparison of the actual creep rate and the ideal creep rate where the creep rate set point is set to a positive value if the actual creep rate is less than the ideal creep rate minus an acceptable differential and is set to a negative value if the actual creep rate is greater than the ideal creep rate plus the acceptable differential, and a means responsive to the creep rate set point for adjusting the operation of the locomotive so that the maximum adhesion value may be realized where the actual creep rate is increased if the creep rate set point is set to the positive value and is decreased if the creep rate set point is set to the negative value.