Part 15 (1/2)
As the princ.i.p.al test of the success of the locomotive was its economy as compared with horse-power, careful calculations were made with the view of ascertaining this important point. The result was, that it was found the working of the engine was at first barely economical; and at the end of the year the steam-power and the horse-power were ascertained to be as nearly as possible upon a par in point of cost.
We give the remainder of the history of George Stephenson's efforts to produce an economical working locomotive in the words of his son Robert, as communicated to Mr. Smiles in 1856, for the purposes of his father's ”Life.”
”A few months of experience and careful observation upon the operation of this (his first) engine convinced my father that the complication arising out of the action of the two cylinders being combined by spur-wheels would prevent their coming into practical application. He then directed his attention to an entire change in the construction and mechanical arrangements, and in the following year took out a patent, dated Feb. 28, 1815, for an engine which combined in a remarkable degree the essential requisites of an economical locomotive,--that is to say, few parts, simplicity in their action, and great simplicity in the mode by which power was communicated to the wheels supporting the engine.
”This second engine consisted, as before, of two vertical cylinders; which communicated directly with each pair of the four wheels that supported the engine by a cross-head and a pair of connecting-rods. But in attempting to establish a direct communication between the cylinders and the wheels that rolled upon the rails, considerable difficulties presented themselves. The ordinary joints could not be employed to unite the engine, which was a rigid ma.s.s, with the wheels rolling upon the irregular surface of the rails; for it was evident that the two rails of the line of railway could not always be maintained at the same level with respect to each other,--that one wheel at the end of the axle might be depressed into a part of the line which had subsided, while the other would be elevated. In such a position of the axle and wheels it was clear that a rigid communication between the cross-head and the wheels was impracticable. Hence it became necessary to form a joint at the top of the piston-rod where it united with the cross-head, so as to permit the cross-head always to preserve complete parallelism with the axle of the wheels with which it was in communication.
”In order to obtain the flexibility combined with direct action, which was essential for insuring power and avoiding needless friction and jars from irregularities in the rail, my father employed the 'ball and socket joint' for effecting a union between the ends of the cross-heads, where they were united with the crank-pins attached to each driving-wheel. By this arrangement the parallelism between the cross-head and the axle was at all times maintained, it being permitted to take place without producing jar or friction upon any part of the machine.
”The next important point was to combine each pair of wheels by some simple mechanism, instead of the cog-wheels which had formerly been used. My father began by inserting each axle into two cranks, at right angles to each other, with rods communicating horizontally between them.
An engine was made upon this plan, and answered extremely well. But at that period (1815) the mechanical skill of the country was not equal to the task of forging cranked axles of the soundness and strength necessary to stand the jars incident to locomotive work; so my father was compelled to fall back upon a subst.i.tute which, though less simple and less efficient, was within the mechanical capabilities of the workmen of that day, either for construction or repair. He adopted a chain, which rolled over indented wheels placed on the centre of each axle, and so arranged that the two pairs of wheels were effectually coupled and made to keep pace with each other. But these chains after a few years' use became stretched, and then the engines were liable to irregularity in their working, especially in changing from working back to forward again. Nevertheless, these engines continued in profitable use upon the Killingworth Colliery Railway for some years. Eventually the chain was laid aside, and the wheels were united by rods on the _outside_ instead of rods and crank-axles inside, as specified in the original patent; and this expedient completely answered the purpose required, without involving any expensive or difficult workmans.h.i.+p.
”Another important improvement was introduced in this engine. The eduction steam had hitherto been allowed to escape direct into the open atmosphere; but my father having observed the great velocity with which the smoke issued from the chimney of the same engine, thought that by conveying the eduction steam into the chimney, and there allowing it to escape in a vertical direction, its velocity would be imparted to the smoke from the engine, or to the ascending current of air in the chimney. The experiment was no sooner made than the power of the engine became more than doubled; combustion was stimulated, as it were, by a blast; consequently, the power of the boiler for generating steam was increased, and in the same proportion, the useful duty of the engine was augmented.
”Thus, in 1815 my father had succeeded in manufacturing an engine which included the following important improvements on all previous attempts in the same direction: simple and direct communication between the cylinder and the wheels rolling upon the rails; joint adhesion of all the wheels, attained by the use of horizontal connecting-rods; and, finally, a beautiful method of exciting the combustion of fuel by employing the waste steam which had formerly been allowed to escape uselessly. It is perhaps not too much to say that this engine, as a mechanical contrivance, contained the germ of all that has since been effected. It may be regarded, in fact, as a type of the present locomotive engine.
”In describing my father's application of the waste steam for the purpose of increasing the intensity of combustion in the boiler, and thus increasing the power of the engine without adding to its weight, and while claiming for this engine the merit of being a type of all those which have been successfully devised since the commencement of the Liverpool and Manchester Railway, it is necessary to observe that the next great improvement in the same direction, the 'mult.i.tubular boiler,'
which took place some years later, could never have been used without the help of that simple expedient, _the steam-blast_, by which power only, the burning of c.o.ke was rendered possible.
”I cannot pa.s.s over this last-named invention of my father's without remarking how slightly, as an original idea, it has been appreciated; and yet how small would be the comparative value of the locomotive engine of the present day, without the application of that important invention.
”Engines constructed by my father in the year 1818, upon the principles just described, are in use on the Killingworth Colliery Railway to this very day (1856), conveying, at the speed of perhaps five or six miles an hour, heavy coal-trains, probably as economically as any of the more perfect engines now in use.”
The invention of the steam-blast by George Stephenson in 1815 was fraught with the most important consequences to railway locomotion; and it is not saying too much to aver that the success of the locomotive has been in a great measure the result of its adoption. Without the steam-blast, by means of which the intensity of combustion is maintained at its highest point, producing a correspondingly rapid evolution of steam, high rates of speed could not have been kept up; the advantages of the mult.i.tubular boiler (afterward invented) could never have been fully tested; and locomotives might still have been dragging themselves unwieldily along at a rate of a little more than five or six miles an hour.
As the period drew near for the opening of the line, the question of the tractive power to be employed was anxiously discussed. At the Brusselton decline, fixed engines must necessarily be made use of; but with respect to the mode of working the railway generally, it was decided that horses were to be largely employed, and arrangements were made for their purchase.
Although locomotives had been regularly employed in hauling coal-wagons on the Middleton Colliery Railway, near Leeds, for more than twelve years, and on the Wylam and Killingworth Railways, near Newcastle, for more than ten years, great scepticism still prevailed as to the economy of employing them for the purpose in lieu of horses. In this case, it would appear that seeing was _not_ believing. The popular scepticism was as great at Newcastle, where the opportunities for accurate observation were the greatest, as anywhere else. In 1824 the scheme of a ca.n.a.l between that town and Carlisle again came up; and although a few timid voices were raised on behalf of a railway, the general opinion was still in favor of a ca.n.a.l. The example of the Hetton Railway, which had been successfully worked by Stephenson's locomotives for two years past, was pointed to in proof of the practicability of a locomotive line between the two places; but the voice of the press, as well as of the public, was decidedly against the ”new-fangled roads.”
When such was the state of public opinion as to railway locomotion, some idea may be formed of the clear-sightedness and moral courage of the Stockton and Darlington directors in ordering three of Stephenson's locomotive engines, at a cost of several thousand pounds, against the opening of the railway.
These were constructed after Stephenson's most matured designs, and embodied all the improvements which he had contrived up to that time.
No. 1 engine, the ”Locomotion,” which was first delivered, weighed about eight tons. It had one large flue, or tube, through the boiler, by which the heated air pa.s.sed direct from the furnace at the one end, lined with fire-bricks, to the chimney at the other. The combustion in the furnace was quickened by the adoption of the steam-blast in the chimney. The heat raised was sometimes so great, and it was so imperfectly abstracted by the surrounding water, that the chimney became almost red-hot. Such engines, when put to their speed, were found capable of running at the rate of from twelve to sixteen miles an hour; but they were better adapted for the heavy work of hauling coal-trains at low speed--for which, indeed, they were specially constructed--than for running at the higher speed afterward adopted. Nor was it contemplated by the directors as possible, at the time when they were ordered, that locomotives could be made available for the purposes of pa.s.senger travelling. Besides, the Stockton and Darlington Railway did not run through a district in which pa.s.sengers were supposed to be likely to const.i.tute any considerable portion of the traffic.
We may easily imagine the anxiety felt by George Stephenson during the progress of the works toward completion, and his mingled hopes and doubts--though the doubts were but few--as to the issue of this great experiment. When the formation of the line near Stockton was well advanced, the engineer one day, accompanied by his son Robert and John Dixon, made a journey of inspection of the works. The party reached Stockton, and proceeded to dine at one of the inns there. After dinner, Stephenson ventured on the very unusual measure of ordering in a bottle of wine, to drink success to the railway. John Dixon relates with pride the utterance of the master on the occasion ”Now, lads,” said he to the two young men, ”I venture to tell you that I think you will live to see the day when railways will supersede almost all other methods of conveyance in this country,--when mail-coaches will go by railway, and railroads will become the great highways for the king and all his subjects. The time is coming when it will be cheaper for a working man to travel on a railway than to walk on foot. I know there are great and almost insurmountable difficulties to be encountered, but what I have said will come to pa.s.s as sure as you now hear me. I only wish I may live to see the day, though that I can scarcely hope for, as I know how slow all human progress is, and with what difficulty I have been able to get the locomotive introduced thus far, notwithstanding my more than ten years' successful experiment at Killingworth.” The result, however, outstripped even George Stephenson's most sanguine expectations; and his son Robert, shortly after his return from America in 1827, saw his father's locomotive generally adopted as the tractive power on mining-railways.
Tuesday, the 27th of September, 1825, was a great day for Darlington.
The railway, after having been under construction for more than three years, was at length about to be opened. The project had been the talk of the neighborhood for so long that there were few people within a range of twenty miles who did not feel more or less interested about it.
Was it to be a failure or a success? Opinions were pretty equally divided as to the railway; but as regarded the locomotive, the general belief was that it would ”never answer.” However, there was the locomotive ”No. 1” delivered upon the line, and ready to draw the first train of wagons on the opening day.
A great concourse of people a.s.sembled on the occasion. Some came from Newcastle and Durham, many from the Aucklands, while Darlington held a general holiday and turned out all its population. To give _eclat_ to the opening, the directors of the company issued a programme of the proceedings, intimating the times at which the procession of wagons would pa.s.s certain points along the line. The proprietors a.s.sembled as early as six in the morning at the Brusselton fixed engine, where the working of the inclined planes was successfully rehea.r.s.ed. A train of wagons laden with coals and merchandise was drawn up the western incline by the fixed engine, a length of nineteen hundred and sixty yards in seven and a half minutes, and then lowered down the incline on the eastern side of the hill, eight hundred and eighty yards, in five minutes.
At the foot of the incline the procession of vehicles was formed, consisting of the locomotive engine No. 1, driven by George Stephenson himself; after it, six wagons loaded with coals and flour; then a covered coach containing directors and proprietors; next, twenty-one coal-wagons fitted up for pa.s.sengers (with which they were crammed); and lastly, six more wagons loaded with coals.
Strange to say, a man on a horse, carrying a flag with the motto of the company inscribed on it, _Periculum privatum utilitas publica_,[18]
headed the procession! A lithographic view of the great event, published shortly after, duly exhibits the horseman and his flag. It was not thought so dangerous a place, after all. The locomotive was only supposed to be able to go at the rate of from four to six miles an hour, and an ordinary horse could easily keep ahead of that.
Off started the procession, with the horseman at its head. A great concourse of people stood along the line. Many of them tried to accompany it by running, and some gentlemen on horseback galloped across the fields to keep up with the train. The railway descending with a gentle decline toward Darlington, the rate of speed was consequently variable. At a favorable part of the road Stephenson determined to try the speed of the engine, and he called upon the horseman with the flag to get out of his way! Most probably, deeming it unnecessary to carry his _periculum privatum_ farther, the horseman turned aside, and Stephenson ”put on the steam.” The speed was at once raised to twelve miles an hour, and, at a favorable part of the road, to fifteen. The runners on foot, the gentlemen on horseback, and the horseman with the flag were consequently soon left far behind. When the train reached Darlington, it was found that four hundred and fifty pa.s.sengers occupied the wagons, and that the load of men, coals, and merchandise amounted to about ninety tons.