Engineering Wonders of the World
Volume I

138 ENGINEERING WONDERS OF THE WORLD VIADUCT ALMOST COMPLETED. of the usual type of dredge with coal and fresh water was impossible, because supplies could not be transported over the shoal lagoons and landed within reach. The dredges used here were operated by gasolene engines. Six of them were constructed on barges. Where there was enough water to float them they waddled across the key, indefatigably heaping up embank- ments. When they came to a dry bit of going they were hauled ashore, mounted on wheels, slid on to a steel track, and so moved ahead as effectively as ever. Upon these embankments miles of trestlework were built, and white coral and sand dumped in. This in time hardens to solid, limestone rock. Then came the graders, followed by the track-layers. In this way key after key was bridged for the iron road. One of the greatest difficulties of the whole undertaking was that of obtaining fresh water, which had to be transported in tanks from Miami, a distance of more than 100 miles. At one time it was thought to cut this distance down by hauling water from Manatee Creek, 50 miles away. Accordingly a water station was put in, and an attempt made to haul water from that point. A north-west wind came along one day and blew the water out of the bay, so that it was impossible for boats to get within two miles of the water station, and they had to go back to Miami until the level of more It has been Track 30 feet above Water. water regained its natural level. Three weeks later the wind came from the south-west, and piled the water up in the bay far above normal level. On the viaducts and embankments in the open sea the track is kept at a than 30 feet above high water, found, after careful examina- tion, that the maximum height of waves throughout these waters is 25 feet. The highest waves known in these regions, therefore, could not break over the top of the viaducts or embankments. It is in the fall of the year, during the months of September and October, that rough weather is experienced in the Bay of Florida. It should be stated, per- haps, that, although the viaducts are of tre- mendous length, they do not by any means complete the connections. For instance, the viaduct across Long Key channel is 10,500 feet in length, but the embankments at each end bring its total length up to 19,100 feet. Many of these ramparts were thrown up by suction dredges, which trailed their long lines of pipe across the channel like huge serpents. These crossings were then riprapped (faced) with rock in order to protect them against the wash of the sea. Here and there, too, special bridges had to be erected. These had to comply with the requirements of the officials at Washington. CLOSE VIEW OF A COMPLETED VIADUCT.