1问题的提出鹰潭编组场是我国江南最大的编组场之一。从1994年底始，原ND3型机车由11台东风7C型机车替代。这为缓解繁忙的编组任务起到良好作用。但一年多来，这11台机车均大量出现同一现象——电动仪表灯、机车速度表灯及WY击穿烧损。有时，在小、辅修中刚换上新的灯管（实际 1 The question put forward Yingtan marshalling yard is one of the largest marshalling yard in Jiangnan of our country. From the beginning of 1994, the original ND3 locomotive was replaced by 11 Dongfeng 7C locomotives. This worked well to ease the busy marshalling tasks. However, over the past year, these 11 locomotives all witnessed the same phenomenon in large numbers - electric instrument lights, locomotive speedometer lamps and WY breakdown burns. Sometimes, in small, minor new just replaced the lamp (actual