NDs型机车是1984年从美国引进的货运机车，至今运用已10年多。最初的换油期是铁道部根据美国GE公司提供的资料统一规定的，机车每走行6万km为一个换油周期，即正常更换机油。运用期间，机车每走行500Ohm，由段化验室对机油进行一次检测，所测项目有不合格者，随时更换机油（为 NDs locomotive was introduced from the United States in 1984 freight locomotive, has been in operation for more than 10 years. The first oil change period is based on the information provided by the United States GE Company unified regulations, the locomotive every 60,000 km for an oil change cycle, that is, the normal replacement of oil. During the operation, each locomotive running 500Ohm, by the laboratory of a section of oil testing, the test items are unqualified, at any time to replace the oil (for