  By THOMAS CURTIS CLARKE. Roman Tramways of Stone—First Use of Iron Rails—The Modern Railway created by Stephenson's "Rocket" in 1830—Early American Locomotives—Key to the Evolution of the American Railway—Invention of the Swivelling Truck, Equalizing Beams, and the Switchback—Locating a Road—Work of the Surveying Party—Making the Road-bed—How Tunnels are Avoided—More than Three Thousand Bridges in the United States—Old Wooden Structures—The Howe Truss—The Use of Iron—Viaducts of Steel—The American System of Laying Bridge Foundations under Water—Origin of the Cantilever—Laying the Track—How it is Kept in Repair—Premiums for Section Bosses—Number of Railway Employees in the United States—Rapid Railway Construction—Radical Changes which the Railway will Effect. The world of to-day differs from that of Napoleon Bonaparte more than his world differed from that of Julius CÆsar; and this change has chiefly been made by railways. Railways have been known since the days of the Romans. Their tracks were made of two lines of cut stones. Iron rails took their place about one hundred and fifty years ago, when the use of that metal became extended. These roads were called tram-roads, and were used to carry coal from the mines to the places of shipment. They were few in number and attracted little attention. The modern railway was created by the Stephensons in 1830, when they built the locomotive "Rocket." The development of the railway since is due to the development of the locomotive. Civil engineering has done much, but mechanical engineering has done more. The invention of the steam-engine by James Watt, in 1773, attracted the attention of advanced thinkers to a possible steam "Soon shall thy arm, unconquered steam! afar Drag the slow barge, or drive the rapid car." First Locomotive. The first locomotive of which we have any certain record was invented, and put in operation on a model circular railway in London, in 1804, by Richard Trevithick, an erratic genius, who invented many things but perfected few. His locomotive could not make steam, and therefore could neither go fast nor draw a heavy load. This was the fault of all its successors, until the competitive trial of locomotives on the Liverpool and Manchester Railway, in 1829. The Stephensons, father and son, had invented the steam blast, which, by constantly blowing the fire, enabled the "Rocket," with its tubular boiler, to make steam enough to draw ten passenger cars, at the rate of thirty-five miles an hour. Then was born the modern giant, and so recent is the date of his birth that one of the unsuccessful competitors at that memorable trial, Captain John Ericsson, was until the present year (1889) living and actively working in New York. Another engineer, Horatio Allen, who drove the first locomotive on the first trip ever made in the United States, in 1831, still lives, a hale and hearty old man, near New York. The earlier locomotives of this country, modelled after the "Rocket," weighed five or six tons, and could draw, on a level, about 40 tons. After the American improvements, which we shall describe, were made, our engines weighed 25 tons, and could draw, on a level, some sixty loaded freight cars, weighing 1,200 tons. This was a wonderful advance, but now we have the "Consolidation" locomotive, weighing 50 tons, and able to draw, on a level, a little over 2,400 tons. And this is not the end. Still heavier and more powerful engines are being designed and built, but the limit of the strength After the success of the "Rocket," and of the Liverpool and Manchester Railway, the authority of George Stephenson and his son Robert became absolute and unquestioned upon all subjects of railway engineering. Their locomotives had very little side play to their wheels, and could not go around sharp curves. They accordingly preferred to make their lines as straight as possible, and were willing to spend vast sums to get easy grades. Their lines were taken as models and imitated by other engineers. All lines in England were made with easy grades and gentle curves. Monumental bridges, lofty stone viaducts, and deep cuts or tunnels at every hill marked this stage of railway construction in England, which was imitated on the European lines. Locomotive of To-day. As it was with the railway, so it was with the locomotive. The Stephenson type, once fixed, has remained unchanged (in Europe), except in detail, to the present day. European locomotives have increased in weight and power, and in perfection of material and workmanship, but the general features are those of the locomotives built by the great firm of George Stephenson & Son, before 1840. When we come to the United States we find an entirely different state of things. The key to the evolution of the American railway is the contempt for authority displayed by our engineers, and the untrammelled way in which they invented and applied The first, and most far-reaching, invention was that of the swivelling truck, which, placed under the front end of an engine, enables it to run around curves of almost any radius. This enabled us to build much less expensive lines than those of England, for we could now curve around and avoid hills and other obstacles at will. The illustration opposite shows a railroad curving around a mountain and supported by a retaining wall, instead of piercing through the mountain with a tunnel, as would have been necessary but for the swivelling truck. The swivelling truck was first suggested by Horatio Allen, for the South Carolina Railway, in 1831; but the first practical use of it was made on the Mohawk and Hudson Railroad, in the same year. It is said to have been invented by John B. Jervis, Chief Engineer of that road. The next improvement was the invention of the equalizing beams or levers, by which the weight of the engine is always borne by three out of four or more driving-wheels. They act like a three-legged stool, which can always be set level on any irregular spot. The original imported English locomotives could not be kept on the rails of rough tracks. The same experience obtained in Canada when the Grand Trunk Railway was opened, in 1854–55. The locomotives of English pattern constantly ran off the track; those of American pattern hardly ever did so. Finally, all their locomotives were changed by having swivelling trucks put under their forward ends, and no more trouble occurred. The equalizing levers were patented in 1838, by Joseph Harrison, Jr., of Philadelphia. Alpine Pass. Avoidance of a Tunnel. These two improvements, which are absolutely essential to the success of railways in new countries, and have been adopted in Canada, Australia, Mexico, and South America, 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 A steep grade on a Mountain Railroad. The climbing capabilities of a locomotive upon smooth rails were not known until, in 1852, Mr. B. H. Latrobe, Chief Engineer of the Baltimore and Ohio Railroad, tried a temporary zigzag gradient of 10 per cent.—that is 10 feet rise in 100 feet length, or 528 feet per mile—over a hill about two miles long, through which the Kingwood Tunnel was being excavated. A locomotive weighing 28 tons on its drivers took one car weighing 15 tons over this line in safety. It was worked for passenger traffic for six months. This daring feat has never been equalled. Trains go over 4 per cent. gradients on the Colorado system, and there is one short line, used to bring ore to the Pueblo furnaces, which is worked by locomotives over a 7 per cent. grade. These are believed to be the steepest grades worked by ordinary locomotives on smooth rails. A Steep Grade on a Mountain Railroad. The climbing capabilities of a locomotive upon smooth rails were not known until, in 1852, Mr. B. H. Latrobe, Chief Engineer of the Baltimore and Ohio Railroad, tried a temporary zigzag gradient of 10 per cent.—that is 10 feet rise in 100 feet length, or 528 feet per mile—over a hill about two miles long, through which the Kingwood Tunnel was being excavated. A locomotive weighing 28 tons on its drivers took one car weighing 15 tons over this line in safety. It was worked for passenger traffic for six months. This daring feat has never been equalled. Trains go over 4 per cent. gradients on the Colorado system, and there is one short line, used to bring ore to the Pueblo furnaces, which is worked by locomotives over a 7 per cent. grade. These are believed to be the steepest grades worked by ordinary locomotives on smooth rails. Another American invention is the switchback. By this plan A Switchback. With the improvement of brakes and more reliable means of stopping trains upon steep grades, came a farther development of the above device, which was first applied on the Denver and Rio Grande Railroad in Colorado, and has since been applied on a grand scale on the Saint Gothard road, the Black Forest railways of Germany, and the Semmering line in the Tyrol. This device is to connect the two lines of the zigzag by a curve at the point Plan of Big Loop. The "Big Loop," as it is called, on the Georgetown branch of the Union Pacific, in Colorado, between Georgetown and a mining camp called Silver Plume, has been chosen to illustrate this point. The direct distance up the valley is 1¼ miles and the elevation 600 feet, requiring a gradient of 480 feet per mile. But by curving the line around in a spiral, the length of the line is increased to 4 miles and the gradient reduced to 150 feet per mile. Zigzags were used first for foot-paths, then for common roads, lastly for railways. Their natural sequence, spirals, was a railway device entirely, and confirms the saying of one of our engineers: "Where a mule can go, I can make a locomotive go." This may be called the poetry of engineering, as it requires both imagination to conceive and skill to execute. Profile of the Same. There is one thing more which distinguishes the American railway from its English parent, and that is the almost uniform practice of getting the road open for traffic in the cheapest manner and in the least possible time, and then completing it and enlarging its capacity out of its surplus earnings, and from the credit which these earnings give it. Big Loop, Georgetown Branch of the Union Pacific, Colorado. The Pennsylvania Railroad between Philadelphia and Harrisburg is a notable example of this. Within the past few years it has been rebuilt on a grand scale, and in many places relocated, and miles of sharp curves and heavy gradients, originally put in to save expense, have been taken out. This system has been followed everywhere, except on a few branch lines, and upon one monumental example of failure—the West Shore Railroad, of New York. The projectors of that line attempted in three years to build a double-track railroad up to the standard of the Pennsylvania road, which had been forty years in reaching its present excellence. Their money gave out, and they came to grief. II.We have thus briefly reviewed the development of our railways to show what they are, and how they came to be what they are, before describing the processes of building, in order that the reasons may be clearly understood why we do certain things, and why we fail to do other things which we ought to do. In the building of a railway the first thing is to make the surveys and locate the position of the intended road upon the ground, and to make maps and sections of it, so that the land may be bought and the estimates of cost be ascertained. The engineer's first duty is to make a survey by eye without the aid of instruments. This is called the "reconnoissance." By this he lays down the general position of the line, and where he wants it to go if possible. Great skill, the result of long experience, or equally great ignorance may be shown here. After the general position of the line, or some part of it, has been laid down upon the pocket map, the engineer sends his party into the field to make the preliminary survey with instruments. In an old-settled country the party may live in farm-houses and taverns, and be carried to their daily work by teams. But a surveying party will make better progress, be healthier and happier, if they live in their own home, even if that home be a travelling camp of a few tents. With a competent commissary the camp can be well supplied with provisions, and be pitched near enough to the probable end of the day's work to save the tired men a long walk. Engineers in Camp. A full surveying party consists of the front flag-man, with his One tent contains the cook, the commissary, and the provisions; another tent or two the working party, and another the superior engineers, with their drawing instruments and boards. In a properly regulated party the map and profile of the day's work should be plotted before going to bed, so as to see if all is right. If it turns out that the line can be improved and easier grades got, or other changes made, now is the time to do it. After the preliminary lines have been run, the engineer-in-chief takes up the different maps and lays down a new line, sometimes coinciding with that surveyed, and sometimes quite different. The parties then go back into the field and stake out this new line, called the "approximate location," upon which the curves are all run in. In difficult country the line may be run over even a third or fourth time; or in an easy country, the "preliminary" surveys may be all that is wanted. The life of an engineer, while making surveys, is not an easy one. His duties require the physical strength of a drayman and the mental accuracy of a professor, both exerted at the same time, and during heat and cold, rain and shine. An engineer, once on a time, standing behind his instrument, was surrounded by a crowd of natives, anxious to know all about it. He explained his processes, using many learned words, and flattered himself that he had made a deep impression upon his hearers. At last, one old woman spoke up, with an expression of great contempt on her face, "Wall! If I knowed as much as you do, I'd quit ingineerin' and keep a grocery!" A large part of the financial difficulties of our railways results from not taking time enough to properly locate the line. It must be remembered that a cheaply constructed line can be rebuilt, but with a badly located line nothing can be done except to abandon it entirely. Royal Gorge Hanging Bridge, Denver and Rio Grande, Colorado. It is well therefore to consider carefully what is the true problem of location. It is so to place and build a line of railway that it shall get the greatest amount of business out of the country through which it passes, and at the same time be able to do that business at the least cost, including both expenses of operating and the fixed charges on the capital invested. The mere statement of this problem shows that it is not an easy one. Its solution is different Veta Pass, Colorado. In a mountainous country, like Colorado, the problem is how to reach the important mining camps, regardless of the crookedness and increased length given to the line. The Denver and Rio Grande has been compared to an octopus. This is really a compliment to its engineers. It sucks nutriment from every place where nutriment is to be found. To do this it has been forced to climb mountains, where it was thought locomotives could never climb. In one place, called the Royal Gorge, the difficulties of blasting a road-bed into the side of the mountain were so great that it was thought expedient to carry the track upon a bridge, and this bridge was hung from two rafters, braced against the sides of the gorge. In surveying some parts of the lines the engineers were suspended by ropes from the top of the mountains and made their measurements swinging in mid-air. Veta Pass, Colorado. In a mountainous country, like Colorado, the problem is how to reach the important mining camps, regardless of the crookedness and increased length given to the line. The Denver and Rio Grande has been compared to an octopus. This is really a compliment to its engineers. It sucks nutriment from every place where nutriment is to be found. To do this it has been forced to climb mountains, where it was thought locomotives could never climb. In one place, called the Royal Gorge, the difficulties of blasting a road-bed into the side of the mountain were so great that it was thought expedient to carry the track upon a bridge, and this bridge was hung from two rafters, braced against the sides of the gorge. In surveying some parts of the lines the engineers were suspended by ropes from the top of the mountains and made their measurements swinging in mid-air. Sections of Snow-sheds. The problem of location is different in an old-settled country, where the position of the towns as trade-centres has been fixed by natural laws that cannot be overruled. In this case the best thing the engineer can do is to get the easiest gradient possible consist 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 stanchly 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.
Snow-sheds, Selkirk Mountains, Canadian Pacific. The winter track under cover; the outer track for summer use. After the railway line has been finally located, the next duty of the engineers is to prepare the work for letting. Land-plans are made, from which the right of way is secured. From the sections, the quantities are taken out. Plans of bridges and culverts are Making an Embankment. The works are then let, either to one large contractor or to several smaller ones, and the labor of construction begins. The duties of the engineers are to stake out the work for the contractors, make monthly returns of its progress, and see that it is well done and according to the specifications and contract. The line is divided into sections, and an engineer, with his assistants, is placed in charge of each. Where the works are heavy, the contractors build shanties for their men and teams near the heavy cuttings or embankments. It is the custom to take out heavy cuttings by means of the machine called a steam shovel, which will dig as many yards in a day as 500 men. 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. If the country contains suitable stone, the culverts and bridge abutments are built by gangs of masons and stone-cutters, who move from point to point. But the general practice is to put in temporary trestle-work of timber resting upon piles, which trestle-work is renewed in the shape of stone culverts covered by embankments, or iron bridges resting on stone abutments and built after the road is running. Building a Culvert. The pile-driver plays a very important part therefore in the construction of our railroads, and has been brought to great perfection. It is worked by a small boiler and engine, and gives its blows with great rapidity. It drags the piles up to leaders and Tunnels are neither so long nor so frequent upon American railways as upon those of Europe. The longest are from two to two and a half miles long, except one, the Hoosac, about four miles. Sometimes they are unavoidable. The ridge called Bergen Hill, west of Hoboken, N. J., is a case in point. This is pierced by the tunnels of the West Shore, of the Delaware, Lackawanna, and Western, and of the Erie, the last two of which, as shown on page 25, are placed at different levels to enable one road to pass over the other. Rock Drill. It is by our system of using sharp curves that we avoid tunnels. It may be said, in general terms, that American engineers have shown more skill in avoiding the necessity of tunnels than could possibly be shown in constructing them. When we are A Construction and Boarding Train. III.From data furnished by Mr. D. J. Whittemore, chief engineer of the Chicago, Milwaukee, and St. Paul system (which had a total length of 5,688 miles on January 1, 1888), the length of open bridges on these lines was 11591/100 miles, and of culverts covered over with embankment, 392/10 miles. "Everything," says Mr. Whittemore, "not covered with earth, except cattle guards, be the span 10 or 400 feet, is called a bridge. Everything covered with earth is called a culvert. Wherever we are far removed from suitable quarries, we build a wooden culvert in preference to a pile bridge, if we can get six inches of filling over it. These culverts Bergen Tunnels, Hoboken, N. J. Mr. Whittemore is an engineer of great experience, skill, and judgment, and there is food for much reflection in these words of his: First—that it is better to use temporary wooden structures, to be afterward renewed in good stone, rather than to build of the stone of the locality, unless first-class. Second—that a structure covered with earth is much safer than an open bridge; which, if short and apparently insignificant, may be, through neglect, a most serious point of danger, as was shown in the dreadful accident of 1887 on the Toledo, Peoria, and Western road in Illinois, where one hundred and fifty persons were killed and wounded, and by the equally avoidable accident on the Florida and Savannah line, in March, 1888. Had these little trestles been changed to culverts covered with earth, many valuable lives would not have been lost. Bergen Tunnels, Hoboken, N. J. Mr. Whittemore is an engineer of great experience, skill, and judgment, and there is food for much reflection in these words of his: First—that it is better to use temporary wooden structures, to be afterward renewed in good stone, rather than to build of the stone of the locality, unless first-class. Second—that a structure covered with earth is much safer than an open bridge; which, if short and apparently insignificant, may be, through neglect, a most serious point of danger, as was shown in the dreadful accident of 1887 on the Toledo, Peoria, and Western road in Illinois, where one hundred and fifty persons were killed and wounded, and by the equally avoidable accident on the Florida and Savannah line, in March, 1888. Had these little trestles been changed to culverts covered with earth, many valuable lives would not have been lost. Beginning a Tunnel. It was safely estimated that there were, in 1888, 208,749 bridges of all kinds, amounting in length to 3,213 miles, in the United States. The wooden bridge and the wooden trestle are purely American products, although they were invented by Leonardo da Vinci in the sixteenth century. From the above statistics it will be seen how much our American railways owe to them, for without them over 150,000 miles could never have been built. The art of building wooden truss-bridges was developed by Burr & Wernwag, two Pennsylvania carpenters, some of whose works are still in use after eighty years of faithful duty (p. 28). A bridge built by Wernwag across the Delaware in 1803 was used as a highway bridge for forty-five years, was then strengthened and used as a railway bridge for twenty-seven years more, and was finally superseded by the present iron bridge in 1875. These old bridge-builders were very particular about the quality of their timber, and never put any into a bridge less than two years old. But when we began to build railways, everything was done in a hurry, and nobody could wait for seasoned timber. This led to the invention of the Howe truss, by the engineer of that name, which had the advantage of being adjustable with screws and nuts, so that the shrinkage could be taken up, and which had its parts connected in such a way that they were able to bear the heavy concentrated weight of locomotives without crushing. This bridge was used on all railways, new and old, from 1840 to about 1870. Had it been free from liability to decay and burn up, we should probably not be building iron and steel bridges now, except for long spans of over 200 feet; and as the table opposite shows, the largest number of our spans are less than 100 feet long. The Howe truss forms an excellent bridge, and is still used in the West on new roads, with the intention of substituting iron trusses after the roads are opened. After 1870, the weights both of locomotives and other rolling stock began to be increased very rapidly. This, together with Old Burr Wooden Bridge. S. Whipple, C.E., published a book in 1847 which was the first attempt ever made to solve the mathematical questions upon which the due proportioning of iron truss-bridges depends. This work bore fruit, and a race of bridge designers sprang up. The first iron bridges were modelled after their wooden predecessors, with high trusses and short panels. Riveted connections were avoided, and every part was so designed that it might be quickly and easily erected upon staging or false works, placed in the river. This was very necessary, for our rivers are subject to sudden freshets, and if we had adopted the English system of riveting together all the connections, the long time required before the bridge became self-sustaining would have been a serious element of danger. Following the practice of wooden bridge building, iron bridges were contracted for by the foot, and not by the pound as is now the custom. To this accidental circumstance is greatly due the development of the American iron bridge. The engineer representing the railway company fixed the lengths of spans, and other By the rule of the survival of the fittest all badly designed forms of trusses disappeared and only two remained: one the original truss designed by Mr. Whipple, and the other, the well-known triangular, or "Warren" girder, so called after its English inventor. It speaks well for the skill and honesty of American bridge engineers that many of their old bridges are still in use, designed for loads of 2,500 pounds per lineal foot, and now daily carrying loads of 4,000 pounds and over per foot. Sometimes the floor has been replaced by a stronger one, but the trusses still remain and do good service. The writer may be permitted to point to the bridge over the Mississippi River at Quincy, Ill., built in 1869, as an example. Most bridge-accidents can be traced to derailed trains striking the trusses and knocking them down. Engineers (both those specially connected with bridge works, and those in charge of railways) know much better now what is wanted, and the managers of railways are willing to pay for the best article. The introduction of mild steel is a great step in advance. This material has an ultimate strength, in the finished piece, of 63,000 to 65,000 pounds per square inch, or forty per cent. more than iron, and it is tough enough to be tied in a knot, or punched into the shape of a bowl, while cold. With this material it is as easy to construct spans of 500 feet as it was spans of 250 feet in iron. Bridges are now designed to carry much heavier loads than formerly. The best practice adopts riveted connections except at the junction of the chord-bars and the main diagonals, where pins and eyes are still very properly used. Plate girders below the track are preferred up to 60 or 70 feet long, then riveted lattice up Kinzua Viaduct; Erie Railway. Valleys and ravines are now crossed by viaducts of iron and steel, of which the Kinzua viaduct, illustrated here, is an example. A branch line from the Erie, connecting that system with valuable coal-fields, strikes the valley of the Kinzua, a small creek, about 15 miles southwest of Bradford, Pa. At the point suitable for crossing, this ravine is about half a mile wide and over 300 feet deep. At first it was proposed to run down and cross the creek at a low level by some of the devices heretofore illustrated in this article. But finally the engineering firm of Clarke, Reeves & Co. agreed to build the viaduct, shown above, for a much less sum than The Manhattan Elevated Railway, about 34 miles long, is nothing but a long viaduct, and is as strong and durable as iron viaducts on railways usually are, while from the slower speed of its trains it is much safer. Kinzua Viaduct; Erie Railway. Valleys and ravines are now crossed by viaducts of iron and steel, of which the Kinzua viaduct, illustrated here, is an example. A branch line from the Erie, connecting that system with valuable coal-fields, strikes the valley of the Kinzua, a small creek, about 15 miles southwest of Bradford, Pa. At the point suitable for crossing, this ravine is about half a mile wide and over 300 feet deep. At first it was proposed to run down and cross the creek at a low level by some of the devices heretofore illustrated in this article. But finally the engineering firm of Clarke, Reeves & Co. agreed to build the viaduct, shown above, for a much less sum than any other method of crossing would have cost. This viaduct was built in four months. It is 305 feet high and about 2,400 feet long. The skeleton piers were first erected by means of their own posts, and afterward the girders were placed by means of a travelling scaffold on the top, projecting over about 80 feet. No staging of any kind was used, nor even ladders, as the men climbed up the diagonal rods of the piers, as a cat will run up a tree. The Manhattan Elevated Railway, about 34 miles long, is nothing but a long viaduct, and is as strong and durable as iron viaducts on railways usually are, while from the slower speed of its trains it is much safer. Kinzua Viaduct. It may not be out of place for the writer to state here what, in his belief, is the next series of steps to be taken to insure safety in travelling over our bridges: Replace, wherever possible, all temporary trestles by wood or stone culverts covered with earth. Where this cannot be done, build strong iron or steel bridges and viaducts with as short spans as possible and having no trusses above the track where it can possibly be helped. Cover these and all new bridges with a solid deck of rolled-steel corrugated plates, coated with asphalt to prevent rusting. Place on this broken stone ballast, and bed the ties in it as in the ordinary form of road-bed. By this means the usual shock felt in passing from the elastic embankment to the comparatively solid bridge will be done away. The improvements in the processes of putting in the foundations of bridges have been as great as those above water. All have shortened greatly the time necessary, and have made the results more certain. The American system may briefly be described as an abandonment of the old engineering device of coffer-dams, by which the bed of the river is enclosed by a water-tight fence and the water pumped out. For this we substitute driving piles and sawing them off under water; or sinking cribs down to a hard bottom through the water. In both cases we sink the masonry, built in a great water-tight box (called a caisson) with a thick bottom of solid timber, until it finally rests on the heads of the piles sawn to a level, or on the top of a crib which is filled with stone, dumped out of a barge. Sometimes it is filled with concrete lowered through the water by special apparatus. Another process, developed within the last twenty years, is to sink cribs through soft or unreliable material to a harder stratum by compressed air. This is an improvement on the old diving-bell. The air, forced into the bell-shaped cavity, expels the water and allows the men to work and remove the material, which is taken up by a device called an air-lock. The crib slowly sinks, carrying the masonry on its top. By this means the foundations of the Brooklyn bridge and of the St. Louis bridge were sunk a little over 100 feet below water. A recent invention is that of a German engineer, Herr Poetsch, who freezes the sand by inserting tubes filled with a freezing mixture, and then excavates it as if it were solid rock. The process of sinking open cribs through the water by weighting them and dredging out the material was followed at the new bridge recently built over the Hudson at Poughkeepsie, where the cribs were sunk 130 feet below water, and at the bridge building over the Hawkesbury River, in Australia. The Hawkesbury piers are sunk to a depth of 175 feet below water, and are the deepest IV.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 word cantilever is used in architecture to signify the lower end of a rafter, which projects beyond the wall of a building, and supports the roof above. It is from an Italian word, taken from the Latin cantilabrum (used by Vitruvius), meaning the lip of the rafter. If two beams were pushed out from the shores of a stream until they met in the centre, and these two beams were long enough to run back from the shores until their weight, aided by a few stones, held them down, we should have a primitive form of the cantilever, but one which in principle would not differ from the actual cantilever bridges. This is another American invention, although it has been developed by British engineers—Messrs. Fowler & Baker—in their huge bridge now building across the Forth, in Scotland, of a size which dwarfs everything hitherto done in this country, the Brooklyn bridge not excepted. 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." View of Thomas Pope's Proposed Cantilever (1810). The first railway cantilever bridge in the world was built by the late C. Shaler Smith, C.E., one of our most accomplished bridge engineers. This was a bridge over the deep gorge of the Kentucky River. The new bridge at Poughkeepsie has three of these cantilevers, connected by two fixed spans, as shown in the illustration (pg. 36). The fixed spans have horizontal lower chords, and really extend beyond each pier and up the inclined portions, to where the bottom chord of the cantilever is horizontal. At these points the junctions between the spans are made, and arranged in such a way, by means of movable links, that expansion and contraction due to changes of temperature can take place. The fixed spans are 525 feet long. Their upper chord, where the tracks are placed, is 212 feet above water. These spans required stagings to build them upon. These stagings were 220 feet above water, and rested on piles, driven through 60 feet of water and 60 feet of mud, making the whole height of the temporary staging 332 feet, or within 30 feet of the height of Trinity Church steeple, in New York. The The cantilever spans were erected, as shown in the illustration on page 37, without any stagings at all below, and entirely from the two overhead travelling scaffolds, shown in the engraving. These scaffolds were moved out daily from the place of beginning over the piers, until they met in the centre. The workmen hoisted up the different pieces of steel from a barge in the river below and put them into place, using suspended planks to walk upon. The time saved by this method was so great that one of these spans of 548 feet long was erected in less than four weeks, or one-seventh of the time which would have been required if stagings had been used. Pope's Cantilever in Process of Erection. (From his "Treatise on Bridge Architecture.") At the Forth Bridge, all the projecting cantilevers will be built from overhead scaffolds, 360 feet above the water. It contains two spans of 1,710 feet each. When spans of this length are used, the rivets become very long—seven inches—and it would be impossible to make a good job by hand riveting. Hence a power-riveter is used in riveting the work upon the staging. A steam-engine raises up a heavy mass of cast-iron, called "the accumulator;" the weight of this in descending is transmitted through tubes of water, and its power increased by contracting the area of pressure, until some twenty tons can be applied to the head of each rivet. One rivet per minute can be put in with this tool. It will be seen that most of the great saving of time in modern construction of bridges and other parts of railways is due to improved machinery. The engineer of to-day is probably not more skilful than his ancestor, who, in periwig and cue, breeches and General View of the Poughkeepsie Bridge. After the road-bed of a railway is completed and covered with a good coat of gravel or stone-ballast, and after all the temporary structures have been replaced by permanent ones, that part of the work may be said to be done, requiring only that the damages of storms should be repaired. But the track of a railway is never done. It is always wearing out and always being replaced. Erection of a Cantilever. Some of the early English engineers, not appreciating this, endeavored to lay down solid stone walls coped with stone cut to a smooth surface, on which they laid their rails. They called this "permanent way," as distinguished from the temporary track of rails and cross-ties used by contractors in building the lines. But experience soon showed that the temporary track, if supported by In laying track on a new railway, if it be in an old-settled country where other railroads are near and the highways good, the ties are delivered in piles along the line where wanted, and the haul of the rails is comparatively short. The ties are laid down, spaced and bedded, adzed off to a true bearing, and the rails laid upon them; the workmen being divided into gangs, each doing a different part of the work. After the track is laid, the ballast-trains come along and cover the roadbed with gravel. The track is raised, the gravel tamped well under the ties, and the track is ready for use. Spiking the Track.
Rail Making. The road is then divided into sections about five miles long. On each section there is a section-boss, with four to six laborers. Their duty is to pass over the track at least twice a day in their hand-car, to examine every joint, and where one is found low or out of line, to bring it back to its true position by tamping gravel under it and moving the track. They have also to see that all They have to see that the fences are all right, that trees and telegraph poles do not fall across the track, that wooden bridges do not burn down, that iron and stone bridges are not undermined by freshets, and always to set up danger signals to warn the trains. Track Laying. It is admitted by competent judges, that the track of the Pennsylvania Railroad is the best in this country, and one of the best in the world. It is kept up to its high standard of excellence by a system of competitive examinations. About the first of November, in each year, after the season's work has been done, a tour of inspection is made over all the lines, on a train of cars expressly prepared, consisting of two or more cars not unlike ordinary box cars with the front end taken out. Each car is pushed in front of an engine, and goes slowly over the line, by daylight only, so that the inspecting party may have a full view of the road. The Pennsylvania road is divided into Grand Divisions, Superintendents' Divisions, of about 100 miles long, Supervisors' Divisions, of about 30 miles, and Subdivisions, of 2½ miles. The examining committee for each Supervisor's Division consists of the supervisors of other divisions. As they pass along, they mark on a card. One sub-committee marks the condition of the alignment and surfacing of the rails; another the condition of As an inducement to the supervisors and the foremen of the Subdivisions to excel on their division, premiums are given as follows: $100 to the supervisor having the best yard on his Grand Division. $100 each to the supervisors having the best Supervisor's Division on each Superintendent's Division of 100 miles. $75 to the foreman having the best subdivision of 2½ miles on each Grand Division. $60 to each foreman having the best subdivision on his Superintendent's Division, including yards. $50 to the foreman having the best subdivision on each Supervisor's Division. In addition to the above there are two premiums of honor given by the general manager, which bring into competition with each other those parts of the main line lying on either side of Philadelphia, viz.: $100 to the supervisor having the best line and surface between Pittsburg and Jersey City. $50 to the second best ditto. If a supervisor or foreman of subdivision receives one of the higher premiums, he is not allowed to be a competitor for any others premiums, except the premiums of honor. The advantages of these inspections and premiums are these: Every man knows exactly what the standard of excellence is, and strives to have his section reach it. Under the old system, a man never got off of his own section, and had no means of comparison, and like all untravelled persons, became conceited. The standard of excellence becomes higher and higher every year. Perfect fairness prevails, as the men themselves are the judges. The officers of the road make no marks, but usually look on and see that there is fair play. This brings the officers and men nearer together, and shows the men how all are working for the common good. An agreeable break is made in the monotony of the men's lives. They have something to look forward to better than a spree. It is by the adoption of such methods as these that strikes will be prevented in the future. It encourages an esprit de corps among the men, and educates them in every way. This system was first devised and put in operation on the Pennsylvania Railroad in 1879, by Mr. Frank Thomson, General Manager, to whom the credit of it is justly due. V.I have thus endeavored to trace the history of the building of a railway; and it must have been seen, from what has been said, that the evolution of the railway and of its rolling stock follows the same laws which govern the rest of the world: adaptation to circumstances decides what is fittest, and that alone survives. The scrap-heap of a great railway tells its own story. Our railways have now reached a development which is wonderful. The railways of the United States, if placed continuously, would reach more than half-way to the moon. Their bridges alone would reach from New York to Liverpool. Notwithstanding the number of accidents that we read of in the daily papers, statistics show that less persons are killed annually on railways than are killed annually by falling out of windows. Railways have so cheapened the cost of transportation that, while a load of wheat loses all of its value by being hauled one hundred miles on a common road, meat and flour enough to supply one man a year can, according to Mr. Edward Atkinson, be hauled 1,500 miles from the West to the East for one day's wages of that man, if he be a skilled mechanic. If freight charges are diminished in the future as in the past, this can soon be done for one day's wages of a common laborer. The number of persons employed in constructing, equipping, and operating our railways is about two millions. The combined armies and navies of the world, while on peace footing, will draw from gainful occupations 3,455,000 men. Those create wealth—these destroy it. Is it any wonder that America is the richest country in the world? The rapidity with which it is possible to build railways over the prairies of the West is extraordinary. It is true that the Temporary Railway Crossing the St. Lawrence on the Ice. The Manitoba system was extended in 1887 through Dakota and Montana, a distance of 545 miles. A small army of 10,000 men, with about 3,500 teams, commanded by General D. C. Shepard, of St. Paul, a veteran engineer and contractor, did it all between April 2 and October 19. All materials and subsistence had to be hauled to the front, from the base of supplies. The army slept in its own tents, shanties, and cars. The grading was cast up from the side ditches, sometimes by carts, and sometimes by the digging machine. Temporary Railway Crossing the St. Lawrence on the Ice. The Manitoba system was extended in 1887 through Dakota and Montana, a distance of 545 miles. A small army of 10,000 men, with about 3,500 teams, commanded by General D. C. Shepard, of St. Paul, a veteran engineer and contractor, did it all between April 2 and October 19. All materials and subsistence had to be hauled to the front, from the base of supplies. The army slept in its own tents, shanties, and cars. The grading was cast up from the side ditches, sometimes by carts, and sometimes by the digging machine. Everything was done with military organization, except that what was left behind was a railway and not earth-work lines of defence. Assuming that this railway, ready for its equipment, cost $15,100 per mile, or $8,175,000, and if it be true, as statisticians tell us, that every dollar expended in building railways in a new country adds ten to the value of land and other property, then this six months' campaign shows a solid increase of the wealth of our It must be remembered that this railway was built after the American system: when the rails were laid, so as to carry trains, it was not much more than half finished; the track had to be ballasted, the temporary wooden structures replaced by stone and iron, and many buildings and miles of sidings were yet to be constructed. But it began to earn money from the very day the last rail was laid, and out of its earnings, and the credit thereby acquired, it will complete itself. And this is only one instance out of many. The armies of peace are working all over our country, increasing our wealth, and binding all parts into a common whole. We have here the true answer to the Carlyles and the Ruskins who ask: "What is the use of all this? Is a man any better who goes sixty miles an hour than one who went five miles an hour?" "Were we not happier when our fields were covered with their golden harvests, than now, when our wheat is brought to us from Dakota?" The grand function of the railway is to change the whole basis of civilization from military to industrial. The talent, the energy, the money, which is expended in maintaining the whole of Europe as an armed camp is here expended in building and maintaining railways, with their army of two millions of men. Without the help of railways the rebellion of the Southern States could never have been put down, and two great standing armies would have been necessary. By the railways, aided by telegraphs, it is easy to extend our Federal system over an entire continent, and thus dispense forever with standing armies. The moral effect of this upon Europe is great, but its physical effect is still greater. American railways have nearly abolished landlordism in Ireland, and they will one day abolish it in England, and over the continent of Europe. So long as Europe was dependent for food upon its own fields, the owner of those fields could fix his own rental. This he can no longer do, owing to the cheapness of transportation from Australia and from the prairies of With the wealth of the landlord his political power will pass away. The government of European countries will pass out of the hands of the great landowners, but not into those of the rabble, as is feared. It will pass into the same hands that govern America to-day—the territorial democracy, the owners of small farms, and the manufacturers and merchants. When this comes to pass, attempts will be made to settle international disputes by arbitration instead of war, following the example of the Geneva arbitration between the two greatest industrial nations of the world. Whether our Federal system will ever extend to the rest of the world, no one knows, but we do know that without railways it would be impossible. When we consider the effects of all these wonderful changes upon the sum of human happiness, we must admit that the engineer should justly take rank with statesmen and soldiers, and that no greater benefactors to the human race can be named than the Stephensons and their American disciples—Allen, Rogers, Jervis, Winans, Latrobe, and Holley. FOOTNOTES:
The approximate total number of bridges in the United States was in 1888:
Probably three-fourths of the truss bridges are now of iron or steel, and may be considered perfectly safe so long as the trains remain upon the rails and do not strike the side trusses. The wooden trestles are a constant source of danger from decay or burning or from derailed trains, and should be replaced by permanent structures as fast as time and money will allow. |
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