CHAP. XVI.] STEPHENSON ON RAILWAY SPEED. 399 formed by the locomotive; but, now that he had established the fact, and greatly exceeded that speed, he was thought behind the age because he recommended it to be limited to forty miles an hour. He said: "I do not like either forty or fifty miles an hour upon any line-I think it is an unnecessary speed; and if there is danger upon a railway, it is high velocity that creates it. I should say no railway ought to exceed forty miles an hour on the most favorable gradient; but upon a curved line the speed ought not to exceed twenty-four or twenty-five miles an hour." He had, indeed, constructed for the Great Western Railway an engine capable of running fifty miles an hour with a load, and eighty miles without one. But he never was in favor of a hurricane speed of this sort, believing it could only be accomplished at an unnecessary increase both of danger and expense. "It is true," he observed on other occasions,*"I have said the locomotive engine might be made to travel a hundred miles an hour, but I always put a qualification on this, namely, as to what speed would best suit the public. The public may, however, be unreasonable; and fifty or sixty miles an hour is an unreasonable speed. Long before railway traveling became general, I said to my friends that there was no limit to the speed of the locomotive, provided the works could be made to stand. But there are limits to the strength of iron, whether it be manufactured into rails or locomotives, and there is a point at which both rails and tires must break. Every increase of speed, by increasing the strain upon the road and the rolling stock, brings us nearer to that point. At thirty miles a slighter road will do, and less perfect rolling stock may be run upon it with safety. But if you increase the speed by say ten miles, then every thing must be greatly strengthened. You must have heavier engines, heavier and better-fastened rails, and all your working expenses will be immensely increased. I think I know enough of mechanics to know where to stop. I know that a pound will weigh a pound, and that more should not be put upon an iron rail than it will bear. If you could insure perfect iron, perfect rails, and perfect locomotives, I grant fifty miles an hour or more might be run with safety on a level railway. But then you must not forget * It may be mentioned that these views were communicated to the author by Robert Stephenson, and noted down in his presence. that iron, even the best, will 'tire,' and with constant use will become more and more liable to break at the weakest point-perhaps where there is a secret flaw that the eye can not detect. Then look at the rubbishy rails now manufactured on the contract system-some of them little better than cast metal: indeed, I have seen rails break merely on being thrown from the truck on to the ground. How is it possible for such rails to stand a twenty or thirty ton engine dashing over them at the speed of fifty miles an hour? No, no," he would conclude, "I am in favor of low speeds because they are safe, and because they are economical; and you may rely upon it that, beyond a certain point, with every increase of speed there is a certain increase in the element of danger." When railways became the subject of popular discussion, many new and unsound theories were started with reference to them, which Stephenson opposed as calculated, in his opinion, to bring discredit on the locomotive system. One of these was with reference to what were called "undulating lines." Dr. Lardner, who at an earlier period was skeptical as to the powers of the locomotive, now promulgated the idea that a railway constructed with rising and falling gradients would be practically as easy to work as a line perfectly level. Mr. Badnell went even beyond him, for he held that an undulating railway was much better than a level one for purposes of working.* For a time this theory found favor, and the "undulating system" was extensively adopted; but George Stephenson never ceased to inveigh against it, and experience has proved that his judgment was correct. His practice, from the beginning of his career until the end of it, was to secure a road as nearly as possible on a level, following the course of the valleys and the natural line of the country; preferring to go round a hill rather than to tunnel under it or carry his railway over it, and often making a considerable circuit to secure good workable gradients. He studied to lay out his lines so that long trains of minerals and merchandise, as well as passengers, might be hauled along them at the least possible expenditure of locomotive power. He had long before ascertained, by careful experiments at Killingworth, that the engine expends half its power in overcoming a rising gradient of 1 in 260, which *Treatise on Railway Improvements." By Mr. Richard Badnell, C.E. CHAP. XVI.] THE NEW SCHOOL OF ENGINEERS. 401 is about 20 feet in the mile; and that when the gradient is so steep as 1 in 100, not less than three fourths of its power is sacrificed in ascending the acclivity. He never forgot the valuable practical lessons taught him by these early trials, which he had made and registered long before the advantages of railways had become recognized. He saw clearly that the longer flat line must eventually prove superior to the shorter line of steep gradients as respected its paying qualities. He urged that, after all, the power of the locomotive was but limited; and, although he and his son had done more than any other men to increase its working capacity, it provoked him to find that every improvement made in it was neutralized by the steep gradients which the new school of engineers were setting it to overcome. On one occasion, when Robert Stephenson stated before a Parliamentary committee that every successive improvement in the locomotive was being rendered virtually nugatory by the difficult and almost impracticable gradients proposed on many of the new lines, his father, on his leaving the witness-box, went up to him, and said, "Robert, you never spoke truer words than those in all your life." To this it must be added, that in urging these views George Stephenson was strongly influenced by commercial considerations. He had no desire to build up his reputation at the expense of railway shareholders, nor to obtain engineering éclat by making "ducks and drakes" of their money. He was persuaded that, in order to secure the practical success of railways, they must be so laid out as not only to prove of decided public utility, but also to be worked economically and to the advantage of their proprietors. They were not government roads, but private ventures-in fact, commercial speculations. He therefore endeavored to render them financially profitable; and he repeatedly declared that if he did not believe they could be "made to pay," he would have nothing to do with them.* Nor was he influenced by the sordid *He often refused to act as engineer for lines which he thought would not prove remunerative, or when he considered the estimates too low. Thus, when giving evidence on the Great Western Bill, Stephenson said, "I made out an estimate for the Hartlepool Railway, which they returned on account of its being too high, but I declined going to Parliament with a lower estimate. Another engineer was employed. Then, again, I was consulted about a line from Edinburg to Glasgow. The directors chalked out a line and sent it to me, and I told them I could not support it in that consideration merely of what he could make out of any company that employed him, but in many cases he voluntarily gave up his claim to remuneration where the promoters of schemes which he thought praiseworthy had suffered serious loss. Thus, when the first application was made to Parliament for the Chester and Birkenhead Railway Bill, the promoters were defeated. They repeated their application on the understanding that in event of their succeeding the engineer and surveyor were to be paid their costs in respect of the defeated measure. The bill was successful, and to several parties their costs were paid. Stephenson's amounted to £800, and he very nobly said, "You have had an expensive career in Parliament; you have had a great struggle; you are a young company; you can not afford to pay me this amount of money; I will reduce it to £200, and I will not ask you for the £200 until your shares are at £20 premium; for, whatever may be the reverses you have to go through, I am satisfied I shall live to see the day when your shares will be at £20 premium, and when I can legally and honorably claim that £200.”* We may add that the shares did eventually rise to the premium specified, and the engineer was no loser by his generous conduct in the transaction. Another novelty of the time with which George Stephenson had to contend was the proposed substitution of atmospheric pressure for locomotive steam-power in the working of railways. The idea of obtaining motion by means of atmospheric pressure originated with Denis Papin more than a century and a half ago; but it slept until revived in 1810 by Mr. Medhurst, who published a pamphlet to prove the practicability of carrying letters and goods by air. In 1824, Mr. Vallance, of Brighton, took out a patent for projecting passengers through a tube large enough to contain a train of carriages, the tube ahead of the carriages being previously exhausted of its atmospheric air. The same idea was afterward taken up, in 1835, by Mr. Pinkus, an ingenious American. Several scientific gentlemen, Dr. Lardner and Mr. Clegg among others, advocated the plan, and an association was case." Hence the employment of another engineer to carry out the line which Stephenson could not conscientiously advocate. * Speech of Wm. Jackson, Esq., M.P., at the meeting of the Chester and Birkenhead Railway Company, held at Liverpool, October, 1845. CHAP. XVI.] ATMOSPHERIC RAILWAYS ADOPTED. 403 formed to carry it into effect. Shares were created, and £18,000 raised; and a model apparatus was exhibited in London. Mr. Vignolles took Mr. Stephenson to see the model; and after carefully examining it, he observed emphatically, "It won't do it is only the fixed engines and ropes over again, in another form; and, to tell you the truth, I don't think this rope of wind will answer so well as the rope of wire did." He did not think the principle would stand the test of practice, and he objected to the mode of applying the principle. The stationary-engine system was open to serious objections in whatever form applied; and every day's experience showed that the fixed engines could not compete with locomotives in point of efficiency and economy. Stephenson stood by the locomotive engine, and subsequent experience proved that he was right. Messrs. Clegg and Samuda afterward, in 1840, patented their plan of an atmospheric railway, and they publicly tested its working on a portion of the West London Railway. The results of the experiment were considered so satisfactory, that the directors of the Dublin and Kingstown line adopted it between Kingstown and Dalkey. The London and Croydon Company also adopted the atmospheric principle; and their line was opened in 1845. The ordinary mode of applying the power was to lay between the line of rails a pipe, in which a large piston was inserted, and attached by a shaft to the framework of a carriage. The propelling power was the ordinary pressure of the atmosphere acting against the piston in the tube on one side, a vacuum being created in the tube on the other side of the piston by the working of a stationary engine. Great was the popularity of the atmospheric system; and still George Stephenson said, "It won't do; it's but a gimcrack." Engineers of distinction said he was prejudiced, and that he looked upon the locomotive as a pet child of his own. "Wait a little," he replied, "and you will see that I am right." It was generally supposed that the locomotive system was about to be snuffed out. "Not so fast," said Stephenson. "Let us wait to see if it will pay." He never believed it would. It was ingenious, clever, scientific, and all that; but railways were commercial enterprises, not toys; and if the atmospheric railway could not work to a profit, it would not do. Considered in this light, he even went so far as to call it "a great humbug." Сс |