Engineering Wonders of the World
Volume I

A RAILWAY THROUGH THE SEA. 133 17 miles run through the Everglades. There are 23 miles of embankment in the open sea. There are 6 miles of viaduct in the open sea. Longest viaduct, 2 miles. Longest gap between islands, 6 miles. Largest island crossed, 16 miles long. Number of islands crossed, 47. Bridges in the open sea, 10. From Key Largo, the first of the islands tapped by the railway, to Long Key, the line To the lay mind these viaducts are the most picturesque part of the whole undertaking. There are four of them, ag- gregating 6 miles in length. .Bridges They extend from Long Key ^Sea to Grassy Key, 10,500 feet ; across Knight’s Key Channel, 7,300 feet; across Moser Key Channel, 7,800 feet ; and across PLACING COFFER-DAMS IN POSITION FOR ARCH FOUNDATIONS. 1 is carried over the sea-gaps between the keys by embankments built up from the ocean bot- tom. Then we reach the first The ... . . of the four arched viaducts. If Viaducts. the engineers had had their way, they would have connected the whole of the forty-seven islands over which the line passes by massive ramparts. But the Government at Washington became uneasy at the notion of a solid wall stretching from the mainland to Key West, fearing that it might shut off the tidal flow, and so disturb the aquatic equi- librium of the Bay of Florida. Therefore the builders were respectfully informed that they must include a certain number of bridges by way of openings in their embankments, in order that the immemorial habits of theltide in this part of the world should not be hampered. Bahia Honda Channel, 4,950 feet. We get some idea of what it meant to erect these via- ducts in the open sea when we learn that that at Long Key consists of no fewer than 186 arches, and is 2 miles in length. In the erection of this particular viaduct 286,000 barrels of cement, 177,000 cubic yards of crushed rock, 106,000 cubic yards of sand, 612,000 lineal feet of piling, 5,700 tons of re- inforcing rods, and 2,600,000 feet of dressed lumber were used. A large fleet of boats had to be chartered to convey this material to the scene of operations. The crushed rock alone filled eighty tramp steamers. Where the water was shallow special rafts had to be constructed to carry the necessary erecting plant, ordinary vessels being used in the deeper water. In the construction of these concrete arches