Gauge for permissible load width on railway - with telescopic observation of actual space within set peripheral interval

摘要

This is for rapid and simple assessment of safety margins along track when moving wide loads between signal posts, telegraph poles, platform sides and other obstacles, comparing the desired peripheral width with the actual width available. The telescope sited at the track has an image from a set distance of the periphery of the desired open space set in its field of vision, and observation is made through it along the track of the real space within the set distance. The image is pref. set at the common focus point of the telescope lens and eyepiece, using a beacon with two spaced aiming-points.