The wear of the wheel flanges of locomotives not only costs a lot of money to change the worn wheels, but also causes even more loss due to the reason that they are temporarily out of service. By lubricating the wheel flanges of a locomotive, the wearing degree of the wheel flanges can be effectively decreased, the wheel can last a long time and the locomotive can run economically. There are two kinds of locomotive wheel-flange-lubrication systems. One adopts the lubrication policy that is based on the fixed time or distance. Although it is simple and low costs, it cannot detect the rail conditions such as curves and pitches, causes unnecessary waste of oil. Besides, it needs a separate sensing system to get the velocity of a locomotive to make lubrication decision. Another one can detect the rail conditions, but it has a complicated sensing system that is in high costs. Its microchip controlling system is proved to be too fragile to be used in the locomotive made in China. Now, there is not a locomotive wheel-flangelubrication system that can detect the rail conditions without a separate sensing system. This paper presents such a locomotive wheel-flange-lubrication system that is simple, effective and low costs. It makes use of the multiprocessor communicating technique to get the run time parameters of a locomotive from the safety information device (black box). Then it uses these parameters to determine the rail conditions and recognize the states of a locomotive. Finally, it adopts a proper policy to lubricate the wheel flange. This approach detects the rail condition and determines the run time conditions without a separate sensing system. It is characterized by simple, efficiency, low costs and low maintenance. It is an electron-mechanic testing and controlling system that adopts microprocessor controlling technology, multiprocessor communication technology and anti-interference technology in a single system. This system has been put into use. The wear of the wheel flanges of locomotives is down 63%, better than that of the other systems.