Excerpt from The Railroad Spiral: The Theory of the Compound Transition Curve Reduced to Practical Formulae and Rules for Application in Field Work The spiral is assumed to leave the tangent at the be ginning of the first chord, at a tangent point known as the Point of Spiral, and designated by the initials P. S., or on the diagrams by the letter S. 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.