A new wheel-slip protective scheme

IMPROVED wheel-slip and wheel-lock protection for diesel-electric locomotives is a subject which has received considerable attention in the past few years. The system here described was designed to meet the proposed specifications of the Association of American Railroads. Its operation is based upon comparison of voltages which are proportional to the speed of the axles being protected. It will operate at the required 5-mile-per-hour speed differential between axles and will correct slipping in the specified manner. A thermally operated delay relay provides protection against abnormal conditions, such as a locked wheel. An additional feature is the provision of wheel-slip indication during dynamic braking. Oscillograms taken in actual train operation indicate that the system performs successfully.