Atlantic Monthly | Page 5

the large amount of ascent encountered, because the load
goes down hill, and the weight of the train is limited only by the
number of empty cars that the engine can take back.
This adoption of steep inclines may be considered as an American idea
entirely, and to it many of our large roads owe their success. The
Western Railroad of Massachusetts ascends from Springfield to
Pittsfield, for a part of the way, at 83 feet per mile. The New York and
Erie Railroad has grades of 60 feet per mile. The Baltimore and Ohio
climbs the Alleghanies on inclines of 116 feet per mile. The Virginia
Central Road crosses the Blue Ridge by grades of 250 and 295 feet per
mile; and the ridge through which the Kingwood Tunnel is bored, upon
the Baltimore and Ohio Railroad, was surmounted temporarily by
grades of 500 feet per mile, up which each single car was drawn by a
powerful locomotive.
Another element, of which American engineers have freely availed
themselves, is curvature. More power is required to draw a train of cars
around a curved track than upon a straight line. In England the radius of
curvature is limited to half a mile, or thereabouts. The English
railway-carriage is placed on three axles, all of which are fixed to the
body of the vehicle; the passage of curves, of even a large diameter, is
thus attended by considerable wear and strain; but in America, the cars,

which are much longer than those upon English roads, are placed upon
a pintle or pin at each end, which pin is borne upon the centre of a
four-wheeled truck,--by which arrangement the wheels may conform to
the line of the rails, while the body of the car is unaffected. This simple
contrivance permits the use of curves which would otherwise be
entirely impracticable. Thus we find curves of one thousand feet radius
upon our roads, over which the trains are run at very considerable speed;
while in one remarkable instance (on the Virginia Central Railroad,
before named) we find the extreme minimum of 234 feet. Such a track
does not admit of high speeds, and its very use implies the existence of
natural obstacles which prevent the acquirement of great velocities.
In fine, the use which the engineer makes of grades and curves, when
the physical nature of the country and the nature and amount of the
traffic expected are known, may be taken as a pretty sure index of his
real professional standing, and sometimes as an index of the moral man;
as when, for example, he steepens his grades to suit the contractor's
ideas of mechanics,--in other words, to save work.
Not less in the construction of bridges and viaducts, than in the
preparation of the road-bed proper, does the American engineering
faculty display itself. Timber, of the best quality, may be found in
almost every part of the country, and nowhere in the world has the
design and building of wooden bridges been carried to such perfection
and such extent as in the United States. We speak here of structures
built by such engineers as Haupt, Adams, and Latrobe, --and not of
those works, wretched alike in design and execution, which so often
become the cause of what are called terrible catastrophes and
lamentable accidents, but which are, in reality, the just criticisms of
natural mechanical laws upon the ignorance of pretended engineers.
Among the finest specimens of timberwork in America are the Cascade
Bridge upon the New York and Erie Railroad, designed and built by Mr.
Adams, consisting of one immense timber-arch, having natural
abutments in the rocky shores of the creek;--the second edition of the
bridges generally upon the same road, by Mr. McCallum, which
replaced those originally built during the construction of the road,

--these hardly needing to be taken down by other exertion than their
own;--the bridges from one end to the other of the Pennsylvania
Central Road, by Mr. Haupt;--the Baltimore and Ohio "arch-brace"
bridges, by Mr. Latrobe;--and the Genessee "high bridge," (not a bridge,
by the way, but a trestle,) near Portageville, by Mr. Seymour, which is
eight hundred feet long, and carries the road two hundred and thirty feet
above the river, having wooden trestles (post and brickwork) one
hundred and ninety feet high, seventy-five feet wide at base, and
twenty-five feet at top, and carrying above all a bridge fourteen feet
high; containing the timber of two hundred and fifty acres of land, and
sixty tons of iron bolts, costing only $140,000, and built in the short
time of eighteen months. This structure, if replaced by an earth
embankment, would cost half a million of dollars, and could not be
built in less than five years by the ordinary mode of proceeding.[2]
Further, the interest,