简述动车组二级检修中车下作业路线（③、④号作业流程）？

<p> <img src="http://que-oss.fenziquan.com/web/akimg/asource/2015052608580219892.jpg"><img src="http://que-oss.fenziquan.com/web/akimg/asource/2015052608580912442.jpg"><img src="http://que-oss.fenziquan.com/web/akimg/asource/2015052608581422696.jpg">车下作业路线（③、④号作业流程）</p>