DESCRIPTION OF A TRAIN BUFFER CARRIAGE FOR THE PREVENTION OF ACCIDENTS ON RAILWAYS. BY SIR GEORGE CAYLEY, BART. SIR,-Permit me through your valuable Magazine to call the attention of the public once more to the means of preventing those horrible railway accidents that seem to be accumulating in an accelerated ratio as an accompaniment to the accelerated velocity now adopted. It may be said, perhaps, that as crows only fly at twentyfour miles per hour, men, not born with wings, ought to be contented to rival in speed those so gifted by nature; and that if they will not be so contented, they should not grumble at the consequences. Still it is our duty, looking at things as they are, to render the risk the least possible. In every attempt of this sort we are invariably met by the present construction of all the enormously expensive apparatus belonging to railroads, and the question is narrowed, not into what might be done on new constructions, but what can be done with little additional cost on the present ones. Certainly some general buffer for every train, must sooner or later, either by the voluntary act of the companies or by the compulsory order of the legislature, be adopted. In my former papers I have proposed a machine of this sort, by having a huge air cylinder and piston placed on wheels; and I still think some modification of that principle, under the advice of our very competent engineers, will be the best way to meet the case. In the mean time, and if we cannot effect the whole, let us try to do a part of the good, by having a series of large cushions or mattresses well packed with some elastic material placed in front of every engine, as represented by A, fig. 1. This may be attached to a hinged tablet or plate, so as to avoid inconvenient length. When on the turning platforms it may be placed in the position B. The little additional weight on the front wheels caused by this buffer will not be of any material consequence, and it would prevent many an injury, though not possibly qualified to meet extreme cases. But in the present state of things, "bis dat qui cito dat." See Mech. Mag., vol. xxxvi. p. 397. The wish of our esteemed correspondent is likely to be soon gratified. Mr. H. S. Rayner, of Ripley, has recently obtained a patent for a system of railway buffers, which will, we believe, fully meet all the difficulties of the case.-ED. M. M. It seems from experience, that the natural tendency of so great a mass of matter as that of a locomotive engine to preserve the right line of its course is such, that, when opposed by the carcase of a cow, or the fragments of the gate, which it smashes in its impetuous course, it generally falls again within the rails; and to obviate those serious accidents that occur from the engine running off the rails, it would be well to take advantage of this principle. The variation of an inch decides the case, and as it so frequently happens to fall within the rails, it is probable, that when it falls without these bounds, the deviation at first is very trifling. Hence, if the front wheels of the engine were provided with three or more grooves each, capable of running on the rail, though not exactly in conformity with the directions of the tender wheels, they would be yet sufficiently so to hold the engine on the rails till the train stops. See C, fig. 2, which represents a section of the lower portion of such a wheel. The adoption of this plan would not imply any alteration of the general line of rails as at present laid; but at the switches and points there would necessarily be a different arrangement. these places the rails must be made in halves, and solid, as at D, when the part leading to the intended new course must remain at its original level, and the other be depressed below the flanch of the wheel as at E. These actions may readily be so coupled by proper machinery, that the one could not take place without the other. At The necessary alterations in the construction of the points of switches to meet this arrangement, may render it necessary to adopt the double flanch, or groove form, in the front wheels of each carriage; in which case it may be well to give them also the advantage of the three grooves in preference to one only, for it frequently happens in accidents that several carriages in succession become the leaders of the train, by those in advance having broken away, and thus the remainder of the train may be preserved on the rail by these extra grooves. I shall not trouble you or your readers with more on this subject at present; but THE LOCOMOTIVE AND ATMOSPHERIC SYSTEMS OF RAILWAY PROPULSION. 147 THE LOCOMOTIVE AND ATMOSPHERIC Sir, There seems to be considerable doubt in the public mind relative to the comparative merits of the locomotive and atmospheric systems of railway propulsion. By first considering what constitute the chief features of a perfect railway system, we shall then be able readily to ascertain where their respective defects lie. A road should require but little embanking, little cutting, and no tunnelling whatever; so as not only to enable the cost for formation to be small, but likewise to prevent the possibility of heavy land-slips. The propelling power should be great, and obtained at a moderate cost, and able to ascend with ease and speed steep inclines, and should be able to stop a train, either at will of the train guards, or at will of a person having a knowledge of its exact position and speed at every point of its journey; and there should be little or no waste of the propelling power, for all, or nearly so, should be absorbed in propelling a train. There should be no disagreeable noise, and not even a possibility of one train running against another, or getting off a line, owing either to sharp curves, or from any other cause; and lastly, great speed should be combined with perfect safety. If we consider the foregoing as de scribing the chief features of a perfect railway system, it will be indisputable that the locomotive system is far, very far, from being perfect. That system compels us to construct a road by forming open cuttings through the lesser hills of earth and rock, tunnelling through those of greater height, and raising viaducts and embankments in valleys. For constructing that road, we have to pour out an immensity of money; and after it is formed, another large sum is wasted in repairing extensive slips in cuttings and embankments; and furthermore, the lives of passengers are endangered by those slips, and by the probability of a mass of rock or chalk falling from perpendicular cuttings upon the rails at night, and overturning a train; and again, our trains are compelled to travel through deep cuttings, over high embankments, and through dark dreary tunnels, thus infusing a degree of terror, especially among the female portion of passengers, which renders railway travelling very unpleasant to them. It is true there is but little danger in passing through even a long tunnel upon a wellregulated line, such as that at Kilsby; but who will say that passing through that or any other tunnel is not disagreeable to him, either on account of fear, the horrible din of the train, its dreary darkness, or the sulphurous smell of the smoke? That system compels us to pay for expensive engines and tenders to run with the trains, and to lay a line with heavier rails than mere passenger carriages would require; and to pay heavily for keeping in repair those engines, inasmuch as the rapidity of their motion induces great wear and tear, and great liability to disarrangement of their working parts; and we have to pay heavily for maintenance of way, principally owing to the great weight of locomotives, and their mode of obtaining a fulcrum upon the rails. We are at an extra outlay for fuel, because stationary condensing engines are much more economical to work than high-pressure locomotives, not only by using the cheaper material, coal, instead of coke; but because, in condensing engines, steam of a low temperature may be advantageously used; and that in all high-pressure locomotives, when travelling at great speed, the used steam upon one side of a piston cannot escape sufficiently fast, thus neutralizing, to a very considerable extent, the propelling power of the steam upon the other side; and, furthermore, steam is wasted by slipping of the driving-wheels, the necessity of having a short stroke and short connecting-rod, and by having to propel a locomotive and its tender with each train. The amount of steam wasted by this latter circumstance will readily be understood by supposing that, out of a train weighing 60 tons, the locomotive and tender weigh 20 tons. It is indisputable that the mere propulsion of the locomotive and tender in this case will absorb one-third of the whole effective power of the engine. Should the weight of the trains be less, of course the loss will be proportionately greater; and lastly, the locomotive system is unsafe, whether a railway has a single or double set of rails; because, unless all those having the charge of locomotives are steady, discreet, and experienced men, the chances of collision between trains, or between an engine and train, are considerable, as the many accidents from collision fully testify. From the preceding remarks, it is evident the locomotive system necessitates us to construct an expensive disagreeable road, and to pay heavily to keep it in good repair; the engines are noisy and expensive in their first cost, expensive to keep in repair, and comparatively very expensive to work; and, moreover the mode of working locomotive railways is attended with considerable danger from collision. Thus, then, although every one must freely admit the locomotive system possesses many advantages over the old system of horse traction, yet it must as freely be allowed that system is but a very imperfect one. The atmospheric railway system is unquestionably superior to the locomotive for short railways, having but one incline, and for level railways, so far as regards safety and economical working; but is unsuited where moderately steep inclines alternately ascend and descend between two termini, because the atmospheric propelling power acts while a train is descending an incline. The chances are, that while descending, what with its previous impetus, the impetus derived. from its own weight, and the propelling power of the piston, the guards would be unable to control the train with their breaks. The consequence would then be, the acceleration of a train to a most dangerous velocity. It is true the atmospheric propelling power can be made to cease acting upon the piston while descending an incline, destroying the vacuum by allowing the outer air free access to the rarefied portion of the tube. This plan is decidedly objectionable, on account of the great loss of power and delay which would be occasioned, as a vacuum would have again to be produced, so that the piston might be propelled after the descent has been accomplished. Another plan is, that immediately upon commencing a descent, the engineman at the terminus is telegraphed to stop the engine; the onward progress of the piston partially destroys the vacuum in the tube, by gradually packing the air within. This plan is objectionable, because it merely slightly lessens the propelling power; and by packing the air within the tube, this latter will have again to be rarefied, and thus cause delay to the train. And lastly, the only other feasible plan is to prevent, by means of a valve in the hindmost of a double piston, the outer air getting access into that portion of the tube behind a train, thus causing the onward progress of the train partially to rarefy the air behind, and so lessen the amount of atmospheric propelling power; but this is manifestly a very. imperfect plan, as it would not, in many cases, lessen the danger, and in others but slightly. In fact, there will always be danger unless the propelling power can be made entirely to cease acting at will. Your readers are doubtless aware that guards cannot apply breaks to the wheels of carriages travelling at high velocity without considerable danger, as a jumping motion is immediately given to those carriages, and they are very likely to jump off the rails in case they meet with a bad joint; and they have a tendency to be thrown off by the hind carriages bumping against and propelling them forward. It is thus obvious the power should not only be enabled to cease propelling, but should be capable of resisting the onward progress of a train at will. The only material loss of power in the atmospheric system results from the outer air getting access into the interior THE COMPUTATION OF DIRECT DISTANCES. of the tube, thus counteracting the efforts of the air-pump to produce a vacuum. This leakage, we must be well aware, owing to the extreme subtlety and expansibility of air, must be very considerable, because it will be next to an impossibility to keep the whole of the valves and piston perfectly air-tight. Air rushes through an almost imperceptible opening into a rarefied space with extraordinary velocity, and takes but a short time to fill a vacuum. This fact necessitates the employment of very large engines to pump out air from the tube. The quicker this is done the better, as the outer air has less time to counteract the efforts of the engine. Other circumstances necessitate the employment of very large engines, which are these, the loss of power arising from increased friction of the engine, and the amount of time occupied in rarefying the tube, which increases rapidly the nearer its interior approaches to a perfect vacuum. For example, if an engine requires to make 50 strokes to produce an unbalanced pressure of 5-6 lbs. upon every square inch of the piston's area, it will require another 50 strokes to produce a pressure of 9.1 lbs. ; another 50 strokes, a pressure of 11.3 lbs. ; and another 50 strokes-that is to say, 200 strokes in all-to produce an unbalanced pressure of 12.6 lbs. Consequently, if it takes 4 minutes to produce an unbalanced pressure of 9.1 lbs., 8 minutes will be consumed in causing that pressure to amount to 12:6 lbs. It is thus clearly manifest that an unbalanced pressure of 9.1 lbs. upon every square inch of the piston's area, may be obtained at half the cost of a pressure of 12.6 lbs. ; but then, on the other hand, a pressure of 91 lbs. is so 149 trifling, as to render necessary a large piston, and consequently a large tube, to obtain sufficient power to propel a train of even moderate weight, thus necessitating larger engines, and increased cost for increased size of the tube. The chief defects of the atmospheric system are, 1st. A road must be as level, or nearly so, as a locomotive line, thus rendering necessary expensive embankments, viaducts, cuttings, and tunnels, simply because the propelling power acts while a train is descending an incline, thus rendering a road possessing bad gradients unsafe. 2nd. The propelling power cannot control a train. 3rd. The great loss by leakage. 4th. The great first cost of machinery, owing to the necessity of having very large engines at every interval of about three miles, to rarefy a large tube quickly. Your readers will thus see that, al- Your obedient servant, 93, Regent-street. THE COMPUTATION OF DIRECT DISTANCES. Sir, I shall now proceed to make a few remarks on "A. B.'s" second problem, vol. xliii. page 4. After a very long geometrical investigation he ultimately arrives at the final equation, Now, cosec. a cos.b=cos. B, sin. a, sin. c + cos. α, cos. c. Now this takes up nearly three columns ; but the proof might be made out in two or three lines from his first equation (vol. xlii. page 412,) viz.,— cos. B cos. b, cosec. a, cosec. c-cot. a, cot. c. = sin. c COS. C sin. c |