调查铁路线路现状的最快最客观的方法是在运行的列车上以离地不高的摄影平台进行摄影的地面立体摄影测量。在这种情况下,用装在车厢或轨道车顶上的悬臂的方式作摄影。悬臂长4～8m,对铁路线路摄影的平台高4.5—5m,铁路线路摄影用焦距55、70、100、152、210mm的摄影机。在摄影高度为5m时,象片比例尺为1:90、1:72、1:50、1:33、1:24。开始摄影之前,把摄影机调置到距线路端点4～5高处,然后根据列车运行的速度计算可 The quickest and most objective way of investigating the status quo of the railway line is to measure the ground stereogram taken with the camera off the ground on the running train. In this case, photography is carried out by means of a cantilever mounted on the roof of a carriage or railroad car. Cantilever length 4 ~ 8m, the railway line photography platform 4.5-5m, the railway line with a focal length of 55,70,100,152,210 mm camera. At a photographic height of 5 m, the image scale is 1:90, 1:72, 1:50, 1:33, 1:24. Before starting photography, the camera is adjusted to the height of 4 to 5 from the end of the line, and then calculated according to the speed of the train running