1　前言　　赤峰机务段配属东风4 型机车 72台 ,东风5型机车 5台。在 1999年入冬至 2 0 0 0年春季这段冬运期间 ,由于所运行的线路状态不好 ,东风4 型机车抱轴螺栓松动、丢失现象十分严重。赤峰机务段行修组补充更换抱轴螺栓日均达 80条之多 ,仅行修 4个组补充丢失的抱轴螺栓一 1 Introduction Chifeng locomotive depot is equipped with 72 Dongfeng 4 locomotives and 5 Dongfeng 5 locomotives. During the winter season from the winter of 1999 to the winter of 2000, the suspension bolts of the Dongfeng 4 locomotive were loose due to the poor running status of the line. The loss was very serious. Chifeng Maintenance Depot repair group to replace the replacement of the axial bolt up to 80 a day, only repair 4 groups to add a missing bolt of a