Page:Miscellaneous Papers on Mechanical Subjects.djvu/167

 the country; to the future is left further progress and improvements.

A single line of rails nailed down to transverse logs, and a train at rare internals, are deemed to be sufficient as a commencement, and as traffic increases, additional improvements can be made.

65. Railway Crossings.—Bridges are seldom thought necessary to carry the common highways across the railroads where they intersect, gates are even in many cases dispensed with, and a notice of "Look out for the locomotive when the bell rings," is considered a sufficient warning, and wayfarers are left to take care of themselves. Sharp curves and steep inclines are frequently submitted to for the sake of economy.

66. Railroad Inclines.—The railroad that connects the eastern and western parts of Pennsylvania, bringing the towns on Lake Erie and the great western rivers into direct communication with Philadelphia and the Atlantic, consists at present of a single line of rails carried over the lofty ridges of the Alleghany Mountains by a series of inclined planes.

These are five in number, and the summit of the highest is 2,000 feet above the level of the sea. The trains are dragged up each incline by