The earliest of the very distinguished list of American bridge-builders erected great timber structures for the highroads and the post-roads. Some of them went back many centuries and came to the stone bridge, in many ways the most wonderful of all the artifices by which man conquers the obstructive power of a running stream. But the building of stone bridges took time and money, and time and money were little known factors in a new land that had begun to expand rapidly.
So at first the railroad followed the course of the highroad and the post-road, and took the timber bridge unto itself. In some cases it actually fastened itself upon the highroad bridge, as at Trenton, N. J., where a faithful wooden structure built by Theodore Burr in 1803 was strengthened and widened in 1848 to take the first through railroad route from New York. It continued its heavy dual work until 1875 when it was superseded by a steel bridge. A dozen years ago the railroad tracks were moved from that structure to a magnificent and permanent stone-arch built near-by. Thus the railroad crossing the Delaware at Trenton has, in this way, typified step by step every stage of the development of American bridge-building.
The timber bridges developed the steel truss bridge, the typically American construction, of to-day. In an earlier day the timber bridges were the glory of the engineer. Sometimes you see one of these old fellows remaining, like the long structure that Mr. Walcott built across the Connecticut River at Springfield, Mass., in 1805, and which still does good service; but the most of them have passed away. Fire has been their most persistent enemy. Within the past two years fire destroyed the staunch toll-bridge at Waterford on the Hudson, just above Troy. The bridge was a faithful carrier for one hundred and four years. In many ways it was typical of those first constructions. It consisted of four clear arch spans--one 154 feet, another 161 feet, the third 176 feet, and the fourth 180 feet in length. It was built of yellow pine, wonderfully hewn and fitted, hung upon solid pegs; and save for the renewal of some of the arch footings, the roof, and the side coverings, it was unchanged through all the years--even though the heavy trolley-cars of a through interurban line were finally turned upon it.