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- View of Thomas Pope's Proposed Cantilever (1810)
The most notable invention of latter days in bridge construction is that of the cantilever bridge, which is a system devised to dispense with staging, or false works, where from the great depth, or the swift current, of the river, this would be difficult, or, as in the case of the Niagara River, impossible to make. The first design of which we have any record was that of a bridge planned by Thomas Pope, a ship carpenter of New York, who, in 1810, published a book giving his designs for an arched bridge of timber across the North River at Castle Point, of 2,400 feet span. Mr. Pope called this an arch, but his description clearly shows it to have been what we now call a cantilever. As was the fashion of the day, he indulged in a poetical description: "Like half a Rainbow rising on yon shore, While its twin partner spans the semi o'er, And makes a perfect whole that need not part Till time has furnish'd us a nobler art." - Steam Excavator
On the prairies of the West the road-bed is thrown up from ditches on each side, either by men with wheelbarrows and carts, or by means of a ditching-machine, which can move 3,000 yards of earth daily. In this case the track follows immediately after the embankment, and the men live in cars fitted up as boarding-shanties, and moved forward as fast as required. - Snow-sheds, Selkirk Mountains, Canadian Pacific
In all countries, old and new, mountainous and level, the rule should be to keep the level of track well above the surface of the ground, in order to insure good drainage and freedom from snow-drifts. The question of avoidance of obstruction by snow is a very serious one upon the Rocky Mountain lines, and they could not be worked without the device of snow-sheds—another purely American invention. There are said to be six miles of staunchly built snow-sheds on the Canadian Pacific and sixty miles on the Central Pacific Railway. The quantity of snow falling is enormous, sometimes amounting to 250,000 cubic yards, weighing over 100,000 tons, in one slide. It is stated by the engineers of the Canadian Pacific, that the force of the air set in motion by these avalanches has mown down large trees, not struck by the snow itself. Their trunks, from one to two feet in diameter, remain, split as if struck by lightning. - A Switchback
Another American invention is the switchback. By this plan the length of line required to ease the gradient is obtained by running backward and forward in a zigzag course, instead of going straight up the mountain. As a full stop has to be made at the end of every piece of line, there is no danger of the train running away from its brakes. This device was first used among the hills of Pennsylvania over forty years ago, to lower coal cars down into the Nesquehoning Valley. It was afterwards used on the Callao, Lima, and Oroya Railroad in Peru, by American engineers, with extraordinary daring and skill. It was employed to carry the temporary tracks of the Cascade Division of the Northern Pacific Railroad over the "Stampede" Pass, with grades of 297 feet per mile, while a tunnel 9,850 feet long was being driven through the mountains. - A Sharp Curve—Manhattan Elevated Railway, 110th Street, New York
Equally valuable improvements were made in cars, both for passengers and freight. Instead of the four-wheeled English car, which on a rough track dances along on three wheels, we owe to Ross Winans, of Baltimore, the application of a pair of four-wheeled swivelling trucks, one under each end of the car, thus enabling it to accommodate itself to the inequalities of a rough track and to follow its locomotive around the sharpest curves. There are, on our main lines, curves of less than 300 feet radius, while, on the Manhattan Elevated, the largest passenger traffic in the world is conducted around curves of less than 100 feet radius. There are few curves of less than 1,000 feet radius on European railways. - Locomotive of To-day
- Rail Making
- The Last Span - ready to join
- The Fury
The “Fury,” built for the Boston and Worcester Railroad in 1849 by Wilmarth. It was known as a “Shanghai” because of its great height. - Pioneer Locomotive
“Pioneer” locomotive. (Drawing by J. H. White.) - Pioneer Locomotive
“Pioneer” locomotive, (1) Safety valve, (2) spring balance, (3) steam jet (4) dry pipe (5) throttle lever (6) throttle (7) crown bar (8) front tube sheet (9) check valve (10) top rail (11) rear-boiler bracket (12) pedestal (13) rocker bearing (14) damper (15) grate (16) bottom rail (17) pump heater valve (18) cylinder lubricator (19) reversing lever (20) brake shoe (21) mud ring (22) blowoff cock (23) ashpan (Drawing by J. H. White.) - Plan of Harpers Ferry Bridge
Shortly after the Harpers Ferry bridge reconstruction, Bollman was made foreman of bridges. It is apparent that, on the basis of his practical ability, enhanced by the theoretical knowledge gained by intense self-study, he eventually came to assist Chief Engineer Benjamin H. Latrobe in bridge design. He later took this work over entirely as Latrobe’s attentions and talents were demanded in the location and extension of the line between Cumberland and Wheeling.