George L. Vose

“ It is the affair of the company’s agent and not of the machinist to know just what a railroad needs. It is a common, and most absurd practice, for a man who is completely ignorant of machinery to order five or ten engines, without the least regard to the character of the road or of the traffic. ”

“ It is perfectly well known by engineers the world over, that with good iron properly used, nothing of the kind ever takes place. This matter used to be a favorite bone of contention among engineers, but it has long since been laid upon the shelf. No engineer at the present day ever thinks of it. We have only to allow the proper margin for safety, as our first-class builders all do, and this antiquated objection at once vanishes. The examples of the long duration of iron in large bridges are numerous and conclusive. ”

“ The tangential force, generated by the motion of the cars, tends to keep the flanges of the wheels against the outer rail; and only when a just balance is made between the tractive and tangential forces, the wheel will run without impinging on either rail, (the wheel being properly coned) . For these forces to balance, there must be a fixed ratio between the weight of a car and the speed, (not the weight of a train, as the shackling allows the cars to act nearly independently, some indeed rubbing hard for a moment against the rail, while the next car is working at ease) . ”

“ LOCOMOTIVES. As the locomotive engine is the power by which railroads are worked, and as its proportions and dimensions are so intimately connected with the physical character of the road, it is thought proper to take space enough at this point to examine the general principles of its construction, and of its adaptation to the work required of it upon railroads. ”

“ What do we know to-day of the quality of the iron rods in any wooden bridge in Massachusetts? It is very doubtful if the best inspection we have in the United States at the present time would have found any defect so evident in the Tariffville bridge as to condemn it as unfit for the passage of trains. There are hundreds of exactly such bridges all over New England, as far as we can tell by the best inspection we now have, made on the same plan, with no more material, and of which we know just as little of the quality of the iron as we did in the Tariffville bridge. ”

“ It will not do to assume, that, because no defects are very evident in a wooden bridge, therefore it has none. When a wooden bridge, originally made of only fair material, has been in use under railroad trains for twenty-five or [Pg 63] thirty years, and in a position where timber would naturally decay, we are bound to suspect that bridge. To assume such a bridge to be all right until we can prove it to be all wrong, is not safe. To assume a bridge to be all wrong until we can prove it to be all right, is a safe method, though not a popular one. ”

“ Any road being divided into locomotive sections, the section given to any one engine should be such as to require a constant expenditure of power as nearly as possible; i. e., one section, or the run of one engine, should not embrace long levels and steep grades. If an engine can carry a load over a sixty feet grade, it will be too heavy to work the same load upon a level economically. It is best to group all of the necessarily steep grades in one place, and also the easy portions of the road; then by properly adapting the locomotives the cost of power may be reduced to a minimum. ”

“ The greatest load that can come upon a single post or rod, is that from the driving wheels of a locomotive. If the whole engine weighs forty tons, there will be ten tons on each pair of drivers, or five tons or 11,200 lbs. on each wheel; which, being applied over a length of ten feet only, may be considered as at a single point, and all parts must be able to bear such load. In large spans, where the weight is great, if the truss is strong enough to support the bridge and load, it will safely resist the effects of a sudden application of passing trains. ”

“ No bridge should be erected in any State without first submitting the plans to the inspector, and receiving his approval, and depositing with him a complete [Pg 86] set of the plans and computations for the work. By this approval is not meant that the inspector is merely to give a favorable opinion as to the plan, but that he is to find, as a matter of fact, whether the proposed dimensions and proportions are such as will make a safe bridge—and just what a safe bridge is, can be plainly defined by law, as it is in Europe, and as it has been proposed by the American Society of Civil Engineers. ”

“ Some writers have considered that the grades of a road should be so adjusted as to equalize the cutting and the filling. The total rise and fall might not be much affected by this, but the mechanical effect of grades might. A perfect balance between the cuts and fills is not to be desired. The whole cost of earthwork must be a minimum, and it is often cheaper to waste and borrow, than to make very long hauls, and to form the grade line by interchange of material on the profile only. ”

“ A poor iron will often show a very fair breaking-strength, but, at the same time, will have a very low elastic limit, and be entirely unfit for use in a bridge. A piece of iron of very inferior quality will often sustain a greater load before breaking than a piece of the best and toughest material, for the reason that a tough but ductile iron will stretch before giving way, thus reducing the area of section, while a hard but poor iron will keep nearly its full size until it breaks. ”

“ Examination of the formula shows how important it is that all trains should run at such a velocity as to demand the same elevation of rail. The absolute elevation must be arranged to meet the requirement of the fastest trains; and other trains must conform, even at a disadvantage.
Note.—The subject of the mechanics of traversing railroad curves, is yet quite in the dark. The action of the train, as caused by its own momentum, is tangential; while the action of the engine tends to pull the cars against the inner rail, being opposed to the first motion. ”

“ This evil affects particularly highway bridges. The ordinary county commissioner or selectman considers himself amply competent to contract for a bridge of wood or iron, though he may never have given a single day of thought to the matter before his appointment to office. The result is, that we see all over the country a great number of highway bridges which have been sold by dishonest builders to ignorant officials, and which are on the eve of falling, and await only an extra large crowd of people, a company of soldiers, a procession, or something of the sort, to break down. ”

“ Besides the annual repairs necessary to maintain a road in proper working order, there is needed a periodic expenditure for reproduction. Evidently the time will come, upon all roads, when rails and sleepers, buildings, bridges, etc., need to be replaced. Knowing the life of rails, we also know the annual depreciation, and from that can easily find what sum must annually be laid aside, which being properly invested, shall, at the end of the life of the rail, together with its interest, be equal to the cost of renewing. ”

“ Evidently a difference should be made in determining the load for London Bridge [Pg 22] and the load for a highway bridge upon a New-England country road in a thinly settled district. A bridge that is strong enough is just as good and just as safe as one that is ten times stronger, and even better; for in a large bridge, if we make it too strong, we make it at the same time too heavy. The weight of the structure itself has to be sustained, and this part of the load is a perpetual drag on the material. ”

“ The conducting power of the metal composing the fire-box and tubes, is one condition which limits the rate of evaporation, when the heat is abundant on the one side and circulation free on the other, as the water certainly carries off the heat as fast as it arrives at the outer surface.
All the heat should be extracted if possible from the gases before they enter the smoke box. We should so arrange the flues, that without so much contracting the passage for the exit of the gases as to need too strong a blast, yet to confine the gases until their full value is extracted. ”

“ As usual, however, in such cases, unprincipled adventurers are not wanting, who, taking advantage of a great demand, do not hesitate to fit up cheap shops, to buy poor material, and to flood the market with a class of bridges made with a single object in view, viz., to sell, relying upon the ignorance—or something worse—of public officials for custom. Not a year passes in which some of these wretched traps do not tumble down, and cause a greater or less loss of life, and [Pg 16] at the same time, with uninformed people, throw discredit on the whole modern system of bridge-building. ”

“ That we may at all times possess these data, we should know every year just the cost of working each article of traffic. It is not enough that the gross receipt exceeds the whole expense; even then the road may be working unprofitably. Unless each item of transport pays for itself, we are taxing unjustly some other item, (except, indeed, in such cases as adopting low rates in order to fill trains running in one direction which would otherwise run empty) . An analysis of cost will also show whether or not it is best to attract an increased amount of business by a reduction of rates. ”

“ This editor certainly would not maintain, that, in itself, it was more important to describe a disaster after it had occurred than to endeavor to prevent the occurrence; but, as a business man, he knew perfectly well that his patrons would read an account giving all of the sickening detail of a terrible catastrophe, while few, if any, would wade through a dry discussion of the means for protecting the public from just such disasters. The public is always very indignant with the effect, but does not care to trouble itself with the cause ”

“ Some engineers express themselves very much in favor of long levels and short but steep inclines. There are cases where the momentum acquired upon one grade, or upon a level, assists the train up the next incline. The distance on the rise during which momentum lasts, is not very great. A train in descending a plane does not receive a constant increase of available momentum, but arrives at a certain speed, where by increased resistance and by added effect of gravity, the motion becomes nearly regular. ”

“ Hundreds of bridges are to-day standing in this country simply because they never happen to have received the load which is at any time liable to come upon them.
A few years ago an iron highway bridge at Dixon, Ill., fell, while a crowd was upon it, and killed sixty persons. The briefest inspection of that bridge by any competent engineer would have been sure to condemn it. A few years later the Ashtabula bridge upon the Lake Shore Railroad broke down under an express train, and killed over eighty passengers. ”

“ I have no hesitation in asserting, that a single track railroad, having judiciously located turnouts, equal, in the aggregate, to one quarter of its entire length, and a well-conducted telegraph, will prove to be a more safe and profitable investment than a much larger sum expended in the construction of a continuous double track, operated without a telegraph. ”

“ In view of the preceding, what shall we say of a bridge company that deliberately builds a bridge in the middle of a large town, where it will be subjected to heavy teaming, and, owing to its peculiar location, to heavy crowds, and warrants to the town that it shall safely hold a ton per running-foot, when the very simplest computation shows beyond chance of dispute that such a load will strain the iron to 40,000 pounds per square inch? ”

“ The coking process is a complete combustion of the volatile principles of the coal. The mass of coal being first kindled at the surface, where it is supplied with an abundance of oxygen, because the doors in front and vents in the rear are open, no more smoke goes from the chimney than from that of a common kitchen fire. The gas generated from the slightly heated coal cannot escape destruction in passing up to the bright flame of the oven. Any deficiency in oxygen for consuming the smoke is supplied by the air entering the grooves of the dampers. ”

“ Dishonest builders cheat ignorant officials, and the public suffers the damage and pays the bills. Is human life worth enough to pay for having these structures inspected, and, if found unsafe, strengthened or removed? Can we do any thing to prevent towns and counties from being imposed upon by dishonest builders? We certainly can, if those who control these matters care enough about it to do it. There are two ways of buying a bridge,—a good way and a bad one ”

“ Accidents from obstacles upon the track, from fire, boiler explosions, and misplaced switches, are no more attendant upon express than upon other trains, but the consequences are worse with the high speeds.
From the analysis above, of one hundred accidents, it appears that eighty-eight per cent. of the cases are due to the causes that are aggravated by increase of speed, and if we assume the aggravation of collision, and breakage of machinery, to be (speed being doubled) as two to one, the danger of travelling a fixed distance, by express, is eighty-eight per cent. ”

“ It will, of course, be understood, when it is said that bridge-building may be called a science, that it can only be so when in the hands of an engineer whose judgment has been matured by wide experience, and who understands that no mechanical philosophy can be applied to practice which is not subject to the contingencies of workmanship. ”

“ Want of increased power, can be an apology for increased gauge, until the capacity of the narrow gauge has been filled. The strongest engines in the world are upon the four feet, eight and one half inch gauge. No engines in America surpass or compare for absolute strength, with those upon the Baltimore and Ohio Railroad. The most powerful passenger engine ever built for high speeds, is Crampton’s engine “Liverpool,” (London and North-western Railroad, England,) gauge four feet, eight and one half inches. ”

“ Drewry, an old but excellent authority, observes that any body of men marching in step at from 3 to 3-1/2 miles an hour will strain a bridge at least as much as double the same weight at rest; and he adds, "In prudence, not more than one-sixth the number of infantry that would fill a bridge should be permitted to march over it in step." Mr. Roebling says, in speaking of the Niagara Falls Suspension Bridge, "In my opinion, a heavy train, running at a speed of 20 miles an hour, does less injury to the structure than is caused by 20 heavy cattle under full trot. ”

“ Suppose the whole load upon the wheels is 60,000 lbs. If the centre of gravity is half-way between the wheels (there being two pairs) , each will support 30,000 lbs. If the centre of gravity is twice as near to one axle as to the other, the furthest one will support 20,000 lbs., and the nearest one 60,000–20,000, or 40,000 lbs.
Suppose the engine has six points of support, or three points in the side elevation, (the ordinary four driving wheels and a truck engine) . Let the centre of gravity be one foot behind the middle axle and the distances between the wheel centres eight feet. ”

“ In one State a late annual report covers a whole railroad with the remark, "All of the bridges on this line are in excellent order;" and yet there were at that very time, and are now, on that road, several large wooden bridges with a factor of safety referred to the breaking-weight of not over two under a fair load, assuming the iron rods to be of the very best material,—a point upon which there is no evidence whatever. ”

“ Engineers are subject to the superintendent of machinery when off, and to the conductor when on, the trains. None but a man well acquainted with the details of machinery, and who has served in a locomotive machine shop, and is in every respect temperate and steady, should fill this berth.
Foremen of the blacksmith, machine, carpenter, and car shops, are subject to the superintendent of machinery, and have charge of the repairs and cleaning of the engines, cars, and other machinery.
Car-masters have charge of the men employed in cleaning, oiling, and examining the cars and their wheels. ”