page_title: Daniel McCallum
section_title: McCallum's Patent Timber Bridge, 1840s-60s
hierarchical_section_title: Daniel McCallum / Work / McCallum's Patent Timber Bridge, 1840s-60s
caption_attribution_description: English: Lithographic drawing of McCullam's Patent Timber Bridge,1852
context_page_description: Daniel Craig McCallum was a Scottish-born American railroad engineer, general manager of the New York and Erie Railroad and Union Brevet Major General during the American Civil War, known as one of the early pioneers of management. He set down a set of general principles of management, and is credited for having developed the first modern organizational chart.
context_section_description: Late 1840s McCallum developed a specific truss bridge construction for the railroad bridges, called McCallum inflexible arched truss. It was constructed principally of pine timber, with less than the ordinary portion of iron rods, blots and casings. An editorial notice from Appletons' Mechanics' Magazine, edited by Julius W. Adams commented on McCullam's Patent Timber Bridge, built in 1851 over the Susquehanna River, near Lanesboro', Pennsylvania, for the New York and Erie railroad.
  We have no hesitation in affirming, that of all the timber bridges patented in this country, there are none, in point of strength, economy (in which we include ultimate durability), facility of repair, and uniformity of action, to be preferred before this plan of bridge lately patented by Mr. D. C. McCallum, of Oswego, engineer or ways and structures on the New York and Erie railroad.
  The bridge shown in elevation (see image) has been built lately for the New York and Erie railroad, at Lanesboro', over the Susquehanna river, in the place of one built by ourselves, several years since, under the orders, and according to the plan of the chief engineer of that road, but which proved unequal to the duty imposed upon it; and its removal became a matter of necessity.
  We objected to the plan of the original bridge, built in that locality, as we have ever done to any plan of the bridge in which the attempt was made to unite the independent systems of arch and truss, and make toe stability of the bridge dependent upon their uniformity of action. In this plan of Mr. McCallum, the two principles are not independent as heretofore; but the action of the arch in the upper chord is made an integral part of the truss itself; and instead of two systems acting unequally, and to the ultimate injury of the structure, we have the best features of both united in a manner which admits of entire uniformity of action.
  In the construction of bridges for railroad purposes, two prominent difficulties have long been discovered, viz., a lack of sustaining principle towards the ends of the trusses and near the abutments, and an entire absence in many cases of a proper counteracting principle to prevent vertical vibration by a moving load. See Haupt on Bridges, to which admirable work the reader is particularly referred for a full description of the proper office of a counter-brace...
  These inflexible arched trusses were used in wooden railroad bridges across the US and Canada in the 19th century.  After his work at the New York and Erie Railroad, in 1858 McCallum founded the McCallum Bridge Company in Cincinnati. The company specialized in railroad bridges, which they build in the Western and Southern States. Some of the Howe truss men were so impressed by McCallum's business success (if not by his arguments) that they began arching their top chords, and a notable example of this practice was the Rock Island Bridge over the Mississippi River. The advent of steel bridges in the 1860s effectively made obsolete his unique design.
caption: Lithographic drawing of McCullam's Patent Timber Bridge, 1852
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