Excerpt from Switch Layouts, And, Curve Easements The theoretical point of a frog may be found as follows Mark the place where the frog is 4 inches wide from gauge to gauge; from this as a beginning, measure toward the point 4 times as many inches as the num ber of the frog. Mark the wing rail opposite, and the latter mark will be opposite the theoretical point of frog. The figures given in the diagrams for the leads (distance. From the point of the frog to the head-block) to frogs in straight main track apply to frogs in the curved main track, provided the main track forms a simple curve within the limits of the lead, except as to the degree of curve of the lead. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.