EXPLANATION.
Stretch a cord measuring exactly a chain (66 feet) across the inner side of the curve, and measure the distance (C D) between the inner edge of the rail and the cord, as shewn in sketch below.
Look for this measurement in the column headed “Offset,” opposite to which, in the column headed “Radius of Curve,” will be found the radius of the curve in chains; and in the columns headed “Minimum Cant” or “Maximum Cant” will be found how much the outer rail is to be raised above the inner one, according to the speed of trains.
