Stories of Inventors - The Adventures of Inventors and Engineers by Russell Doubleday
page 95 of 140 (67%)
page 95 of 140 (67%)
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who has seen the rushing, roaring, foaming waters of unknown depth that
race so fast from the spray-veiled falls that they are heaped up in the middle, the mere thought of men handling huge girders of steel above the torrent, and of standing on frail swinging platforms two hundred or more feet above the rapids, causes chills to run down the spine; yet the work was undertaken without the slightest doubt of its successful fulfilment. It was manifestly impossible to support the new structure from below, and the old bridge was carrying about all it could stand, so it was necessary to build the new arch, without support from underneath, over the foaming water of the Niagara rapids two hundred feet below. Steel towers were built on either side of the gorge, and on them was laid the platform of the bridge from the towers nearest to the water around and under the old structure. The upper works were carried to the solid ground on a level with the rim of the gorge and there securely anchored with steel rods and chains held in masonry. Then from either side the arch was built plate by plate from above, the heavy sheets of steel being handled from a traveller or derrick that was pushed out farther and farther over the stream as fast as the upper platform was completed. The great mass of metal on both sides of the Niagara hung over the stream, and was only held from toppling over by the rods and chains solidly anchored on shore. Gradually the two ends of the uncompleted arch approached each other, the amount of work on each part being exactly equal, until but a small space was left between. The work was so carefully planned and exactly executed that the two completed halves of the arch did not meet, but when all was in readiness the chains on each side, bearing as they did the weight of more than 1,000,000 pounds, were lengthened just enough, and the two ends came together, clasping hands over the great gorge. Soon the tracks were laid, and the new bridge took up the work of the old, and then, piece by piece, the old suspension |
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