Comparative Weight of India-rubber and Steel Springs. 9251 82 51 Carriage-Bearing, Drawing, & Buffing Springs... 41 Waggon-Bearing, Drawing, & Buffing Springs... 3 2ndly. Steadiness of motion. This has been referred to before; and it may be added that the great steadiness of the engines with the India-rubber springs is the surprise of every one who has witnessed their performance upon the imperfect road on which they are worked. 3rdly. Durability. Although sufficient time may not have elapsed to test the absolute durability of these springs, yet during the time they have been in use, in consequence of the heaviness of the work, if deterioration had commenced ever so slightly, it would have been observable; but in a large number of the Indiarubber cylinders that were examined, after being at work for various periods, varying from four to six months, in both engines, carriages, and waggons, in no instance was the slightest alteration visible from the day in which they were first used, nor the slightest permanent contraction in length or expansion in diameter perceptible: it may, therefore, be inferred, that their durability far exceeds anything hitherto applied to the same purpose, and is fully equal to any reasonable expectation or requirement. The specimens shewn to the meeting, having been in use for the last five or six months, corroborated this statement. The weight on each pair of the engine springs is from 4 to 9 tons. 4thly.-Saving in repairs. The simple construction of these springs renders it almost impossible for any injury to happen to them; consequently little or no repairs are needed. As stated before, the cost of repairing the steel springs of fifteen engines, for six months, was £251. 9s. 9d. The cost of repairing the India-rubber springs of fourteen engines, during the last six months, was only £1. 188. The saving in the cost of repairs is not confined to the springs alone, but the engine itself: the carriages and waggons to which they are applied, and even the permanent way, share the advantage. It is found that fewer chairs are broken, fewer rails (plates rather) are bent, less grease and oil is used for the bearings, and the cost of maintaining the waggons is reduced when India-rubber is used. It is inferred, with a considerable degree of probability, that, from the absence of any jerk upon the axles, the tendency of the iron to become crystallized or altered in its nature, and suddenly fracturing, so often complained of, and which has produced so many serious accidents upon railways, will, by the use of these springs, be nearly overcome, and the axles remain perfect for a much longer period; more especially as under the India-rubber springs they shew no tendency to heat. 5thly. Cost. The question of first cost does not properly belong to this paper, but it will be sufficient to state that a wellconstructed India-rubber spring ought not, in any case, to exceed the cost of a steel spring of equal strength; but on the hydropneumatic principle it will be found to be considerably cheaper, especially for engines, amounting, on an average, to 20 per cent. saving on the old plan. The foregoing remarks have been made chiefly with reference to bearing springs; but they apply equally to both buffer and draw springs; and in proportion to the extent in which Indiarubber is used in place of steel, does the improvement in the rolling stock become apparent, and the benefit resulting from its use more strongly develope itself. The pneumatic buffers, it is considered, have been subjected to a peculiarly severe test,-few lines of railway in the kingdom possessing such disadvantageous circumstances. Almost every other description of buffer had been tried previously with the same want of success, until, from repeated failures, the attempt to obtain a permanent buffer was almost abandoned in despair, and solid blocks of wood were substituted for them in many instances. With these buffers, however, no failure has taken place, nor in any instance has their elasticity diminished in the slightest degree. In the accompanying table, the deflection of this description of buffer and the several kinds of springs, under different weights, is shewn. Before the application of India-rubber draw-springs to the engines and tenders, the couplings were frequently breaking, and also the frame ends: but since their adoption nothing of the kind takes place. Such are the advantages of these springs that their adoption promises to become general, and it will be shortly, without doubt, as rare to meet with a waggon unprovided with a draw-spring, as it was formerly to meet with one. In working 15,000 miles, the cost of repairs is found to be reduced in the engines using India-rubber springs, in corresponding engines of the two classes, from 54d. to 3 d. per mile, and from 7d. to 34d. per mile. It has been the writer's object in this paper to state rather what has been done than to speculate on what will be; but it is notorious that the ordinary steel springs are deficient in point of general efficiency, whether as regards elasticity, durability, or cheapness. It may be that competition may cause their manufacture to be less strictly attended to than formerly; or it may be, and most likely is, that the requirements of the present day have outstripped their ability to perform. However, be that as it may, it is well known that a substitute which shall combine the above requisites has been long desired; and the writer's hope, therefore, that this desideratum will now be supplied by the springs which have been described, must be his apology for bringing the subject before the Institution. Mr. Craig exhibited a set of the different descriptions of Indiarubber springs described in the paper, and also specimens of the India-rubber cylinders, taken out of various springs which had been at work on the Monmouthshire Railway, to shew the effects of wear upon them. One cylinder had worked 8,850 miles in the bearing spring of an engine; another 14,060 miles in a carriage bearing spring; and an engine buffer spring that had been six months in constant use was shewn: all of these appeared uninjured by the work, and not to have suffered any permanent compression. Mr. H. Wright observed that he had seen these India-rubber springs at work on the Monmouthshire Railway, and they certainly worked very satisfactorily, and were much better adapted to that situation than steel springs. The case of that railway was very peculiar; it was perhaps the worst in the kingdom for destructive action on the springs, from the great inequality and roughness of the road, which was not upon the edge-rail, but the old tramway system, and with very sharp curves; it was, indeed, impossible for steel to stand in the engine springs; but the India-rubber springs appeared to stand the work well. Mr. W. A. Adams said he was acquainted with these Indiarubber springs, and had witnessed their working on the Monmouthshire line; it was previously impossible to keep steel springs in order, from the violent jerks they were subjected to, and the substitution of India-rubber for steel in that case was an important improvement. As to the general application of Indiarubber springs, there was a special circumstance in favor of their use in locomotive engines, from the confined position and the want of space to fix a properly proportioned laminated steel spring, which might probably be otherwise made to work satisfactorily; but the steel springs generally used in locomotives were so short and stiff, that their elastic action was exceedingly imperfect, and they were consequently ill suited to withstand the violent concussions of a rough road. In the bearing springs of carriages the case was very different; and a long, thin laminated spring was employed, which had a very easy, elastic action; so that in that case the advantage would be less felt of the substitution of India-rubber for steel. In applying the India-rubber springs to carriages, it had to be observed that the bearing of the frame would be on four points only, instead of eight,-requiring a stronger frame or cross-bars to distribute the strain. Mr. Allan said he had made some trial of these India-rubber bearing springs on engines, and they worked very well-but he found them too elastic, and liable to produce a jumping action; but the springs he had tried were of the kind first described, without provision for checking the rebound of the spring. The Chairman inquired whether, if such re-action could be removed, the India-rubber spring would be considered superior to steel? Mr. Allan thought that very little friction or resistance would be sufficient to check the re-action; and the India-rubber would then certainly make a very good spring. Mr. Craig observed, that the rebound complained of was quite stopped by the little resistance offered by the small second spring that had been subsequently introduced; but it was now found that the objection was quite removed by the water application in the new compound spring. Mr. Clift inquired whether any difference was found between winter and summer in the action of the India-rubber? whether there was any more oscillation observed in hot than in cold weather? and whether the India-rubber was liable to any injury by the heat to which it was liable to be exposed from the boiler or fire-box of the engine? Mr. Craig replied, that the India-rubber was not affected by the temperature, and no effect was found during the last severe winter; also, in two tank engines, one pair of the India-rubber springs was exposed to great heat, probably as much as 240°, being very near the fire-box, but there was no perceptible effect. The material used for the springs was Moulton's prepared Indiarubber the raw gum would not stand exposure to heat, and the constant compression and elastic action. The Chairman inquired what pressure there was upon the Indiarubber when the springs were at work? Mr. Craig replied, that the vertical pressure on the end of the India-rubber cylinder, in the engine bearing springs, amounted to about 14 cwt. per square inch; a weight of 4 tons being supported on a cylinder 9 inches diameter, having a 14-inch hole in the centre. In the hydro-pneumatic spring the pressure on the India-rubber was about 2 cwt. per square inch: he intended trying the exact pressure of the water with a Bourdon's pressure gauge, but had not been able to complete the experiments in time for the present meeting. Mr. E. A. Cowper observed, that he understood a considerable trial of India-rubber springs had been made on engines upon the London and North-Western Railway, and inquired what kind of spring had been applied there, and what were the results? He had also heard that on the Great Western they used India-rubber springs, and now never hung an engine any other way. Mr. Craig replied, that the springs tried on the London and North-Western were with two or three cylinders of India-rubber, similar to the first arrangement described, and they were working very satisfactorily, and, he believed, were preferred to steel springs. The Chairman inquired the relative cost of India-rubber and steel springs? Mr. Craig said, that the cost of the India-rubber springs did not in any case exceed that of steel. Waggon springs were about £3. 188. per set; but engine springs were considerably less expensive than steel, there being so much greater proportionate weight of steel in the ordinary springs. By the introduction of water in the improved springs, the quantity of India-rubber to support the same weight was reduced from 20 lbs. to 12 lbs. in each spring, which, at the cost of two shillings per pound, effected a considerable saving in the expense. A considerable saving in respect of grease had also been observed, but not being able to give the exact results, he would make a comparative trial for the purpose of determining that point. The following paper "On railway axle lubrication," by Mr. W. BRIDGES ADAMS, of London, was next read : ances. : In the economy of railway transit an idea has prevailed that increase of speed increases cost in a compound proportion, in many other things than the mere excess of fuel consumed in the locomotive. This is correct only in reference to imperfect appliIf, for example, the rails deflect beneath the rolling loads, the substructure will be displaced, and increased speed will greatly increase the displacement. If the wheel peripheries be out of order, the greater the speed the greater will be the destruction; and so also if the rail surfaces or joints be out of order. And in proportion as the springs are inefficient, i. e., are non-elastic, or do not act through sufficient space to moderate the shocks, so will the destructive wear be increased by increased speed. But were VOL. XLIII. F |