简述机车信号测试环线检修质量标准？
["JT-C\u7cfb\u5217\u673a\u8f66\u4fe1\u53f7\u7684\u663e\u793a\u673a\u6784\uff0c\u81ea\u4e0a\u800c\u4e0b\u7684\u6392\u5217\u987a\u5e8f\u662f\uff1a\u7eff\uff08L\uff09\uff0c\u7eff\u9ec4\uff08LU\uff09\uff0c\u9ec4\uff08U\uff09\uff0c\u9ec42\uff08U2\uff09\uff0c\u7ea2\u9ec4\uff08HU\uff09\uff0c\u53cc\u9ec4\uff08UU\uff09\uff0c\u7ea2\uff08H\uff09\uff0c\u767d\uff08B\uff09\uff0c\u5176\u4e2d\u9ec42\u706f\u4e3a\u5e26\u201c2\u5b57\u201d\u7684\u9ec4\u706f"]