You are standing aloft, balancing yourself upon tiny planks at the steadily advancing end of the bridge, as it forces itself over a stream of formidable width. Overhead, a gigantic, ungainly traveller, equipped with steel derricks at every corner, is advancing foot by foot as the bridge advances foot by foot. Underneath, through the thin network of planks, of girder and of supporting false work, you can see the surface of the river a full hundred feet below. A steamboat is passing directly beneath you. From your perch she looks like a great yellow bird. Those fine black specks upon her back are the humans who are gathered upon her upper deck.
Whistles call and the derricks groan as they swing the thousands of bridge-members, that are flying together at the beck of the engineer, into their final resting-places. There is the deafening racket of the riveters, here and there and everywhere. There are crude railroad tracks upon the temporary flooring of the bridge deck, and the calls of the dummy locomotives add to the racket. The railroad tracks lead to the shore, to temporary yards where the bridge materials are assembled as fast as they come from the shops in a city three hundred miles distant.
For, remember that while the sand-hogs were burrowing under the surface of the river to find footholds for this monster, other men were burrowing into the hillsides to find the precious ore for the welding of his muscles. A hundred thousand picks must have fought in his behalf, furnaces blazed for miles before the crude ore became the finished, perfect steel. Of the forging and the rolling of the steel a whole book might be written. It is enough now to say that of the 50,000,000 pounds of steel, every pound was made on honor. The railroad had its inspectors everywhere, but the rolling-mill men held to their formulas for perfect steel, and perfect steel was the result. A slight flaw in the metal, and possibly at some unexpected day, a great catastrophe. The safety of human life was upon the men who forged the steel, and they forged honor into every great girder, into every rod and bolt and plate. This conqueror of the river was a warrior built in honor.
The safety of human life depends upon the men who build this bridge. Study carefully the face of this man who stands beside you, the man who evolved this bridge as a season’s work of his restless mind. His face is the face of a man who has high regard for human safety; that factor creeps to the fore as he talks to you. He is telling of the method of constructing the upper works of a bridge of this size.
“We’re getting ahead all the time,” he laughs, “and we’re moving rather forward in our construction methods. In an older day we did this work with derricks of a rather simple sort, operated them by small portable steam engines. You can’t handle bridge-members—units that are only held down by the clearances of tunnels and the transporting powers of the railroads—that way to-day. We’ve nearly half a million dollars tied up here in constructing-appliances. These steel-boom derricks, travellers, and steel-wire hoists, the compressing engines for handling the riveters, cost big money.
“Our method? That’s a simple enough affair as a rule. We set up this spindly tower on rails, that we call the ‘traveller’ and it moves backwards and forwards over the trusses and the timber falsework that we build before the steel really begins to be set up. When the steel—the trusses—is up and riveted, then away with the falsework. Our bridge stands by itself. You can put up a 500-foot span in no time at all by using the falsework.”
You make bold to ask what the engineer does when the river is too deep to admit of falsework. He is quick to answer.
“We generally fall back on a cantilever,” he says, without hesitation. Then he begins to tell you about one of the latest of American problems—the new bridge of the Idaho & Washington Northern Railroad, just now being built over the Pend Oreille River, Washington. They could span that narrow cleft only on the cantilever principle, and when they began to balance their cantilever, there was not enough room for the back arm. But the engineers only chewed off fresh cigars and began forcing their great span out mid-air. They made the balance by placing 600 tons of steel rails on the back-arm. For every foot the span reached out anew over a so-called “bottomless” they added a few more rails. You can generally trust an engineer in such a time as that.
Look closely now upon the workmen who are fabricating this giant bridge. Look closely upon them. They are different from those whom we saw toiling in the caissons below. Scandinavians may and do toil as sand-hogs at the bottom of the stream; Lithuanians may mine the ore, and Hungarians roll it into steel; Americans build upon their toil and erect this bridge. These builders speak no unfamiliar tongue. They are the product of Ohio, the Middle West, the South, the Pacific Coast, New England; they rise immeasurably superior to every other class of labor employed upon the work. Some of them have been sailors, and their talk has the savor of the sea. All of them are men, clear-headed, cool-headed, true-headed men.
If you come upon them at the noon-hour, sprawled along the narrow ledge of a single plank you may be impressed by two things—their Americanism and their cosmopolitanism. The first of these is writ upon each man as you look at him; the second is evident in talk with him. This big fellow must have been a sheriff out in Montana, and he must have been a sheriff for bad men to dodge; his neighbor is talking about his last job, a sky-high cantilever down in Peru. The two side-partners over by the tool-box are just back from India. American bridge-building talent encircles the world. Here is a boss who got his first training down on the Nile; his assistant has done some mighty big work on the Trans-Siberian.