L-shaped track ruler

L-shaped track ruler is also called right-angle track ruler. Its common names include L-shaped track caliper, right-angle track ruler, base mark ruler, etc. L-shaped track ruler (full track type) is a special measuring tool used to measure the distance between the outer side (or inner side) of the railway track and the center of the base mark positioning hole and the height between the plane on the rail and the base mark.