. The American railway; its construction, development, management, and appliances . bold work done in the con-struction of the road upon a mountain side. It must be supportedwhere necessary by walls built up from suitable foundations, oftenonly secured at a great depth below the grade of the road. Pro-jecting points of rock must be cut through, and any practicablenatural shelf or favorable formation must be made use of, as in thepicture on page 61. In some of the mountain locations, gallerieshave been cut directly into the rock, the cliff overhanging the road-way, and the line being carried in
. The American railway; its construction, development, management, and appliances . bold work done in the con-struction of the road upon a mountain side. It must be supportedwhere necessary by walls built up from suitable foundations, oftenonly secured at a great depth below the grade of the road. Pro-jecting points of rock must be cut through, and any practicablenatural shelf or favorable formation must be made use of, as in thepicture on page 61. In some of the mountain locations, gallerieshave been cut directly into the rock, the cliff overhanging the road-way, and the line being carried in a horizontal cut or niche in thesolid wall. The Oroya and the Chimbote railways in South Americademanded constant locations of this character. At many pointsit was necessary to suspend the persons making the preliminarymeasurements from the cliff above. The engineer who made theselocations told the writer that on the Oroya line the galleries wereoften from 100 to 400 feet above the base of the cliff, and were gener-ally reached from above. Rope ladders were used to great advan-. SURVEYING ON ROPE LADDERS. 53 tage. One 64 feet long and one 106 feet long covered the usualpractice, and were sometimes spliced together. The side ropeswere f and i^ inches in diameter, and the rounds of wood \\ inchesin diameter, and 16 inches and 24 inches long. These were notchedat the ends and passed through the ropes, to which they were after-ward lashed. These ladders could be rolled up and carried abouton donkeys or mules. When swung over the side of a cliff andsecured at the top, and when practicable at the bottom, they formeda very useful instrument in location and construction. For simpleexamination of the cliff, and for rough or broken slopes not exceed-ing 70 to 80 degrees, an active fellow would, after some experience,walk up and down such a slope simply grasping the rope in hishands. If required to do any work he would secure the ropeabout his body, or wind it around his arm, leaving his
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishernewyorkcscribnerss
