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March 1,1868.] THE CIVIL ENGINEER AND ARCHITECT’S JOURNAL. 77 doubt so, but it cannot materially affect the question, for if the whole average of 198 passengers travelled 1] mile, there would be none the remaining 3 miles ; the only difference in the pro portion of paying to unpaying load which could arise from this would be a slight increase of the former to the latter for mile only, while for the 3 miles it would be wholly dead load. To prove the correctness of this calculation, we have only to assume what many might be disposed to imagine, that 198 passengers instead of 55 are carried per train per mile, the result would give 101,293,854 instead of nearly 24,000,000 now carried. Nothing could be more appropriately said at this moment than the following quotation from Professor Gordon’s pamphlet, written twenty years ago. At page 24 he says “ These figures indicate the small portion of the mechanism of the railway sys tem of transport that is actually brought into requisition even on the most frequented lines. Thousands, nay, millions of miles, are run by locomotives and carriages on the present sys tem, whilst they are performing an amount of transport of pas sengers preposterously disproportioned to the power and capa city of the trains employed for effecting it.” Contrast this condition of things on the Metropolitan Railway with our ordinary omnibus traffic. We find that the omnibus which has to travel over an infinitely worse road than any line, weighs somewhere about one ton, whilst it carries 28 passengers or two tons, thus giving a proportion of two tons of paying to one ton of unpaying load ; but as we have included the weight of the horse, i.e., the locomotive engine in the calculation on the metropolitan working, it is hut fair to include the horses which haul the omnibus. Two horses with every equipment cannot weigh a ton, consequently at the very outside, the pro portion is one to one, or one ton of paying load to one ton of material employed to convey it. These are very suggestive facts; they have supprised me; and that this line has earned any dividend at all under these circumstances proves its enor mous productive capabihty. Beyond the question of propor tion of effective to non-effective duty, let us consider how it all bears on the maintenance of the railway stock and road, and how they are affected thereby. I have already given the weights of the locomotives and carriages, the former at 42 and the latter at 16 tons each. The carriages have very long wheel bases, consequently they offer great resistance to the tractive force of the engine, besides being very injurious to the rails rounding the curves. The engines have 32 tons on 4 wheels,, or 16 tons per pair. We have only to imagine this enormous weight ploughing along at 30 miles an hour to form some idea of the destructive effect, not only to the rails, but to the substructure and the machines, the effect being destructive alike to all. No wonder that the line has, as it is stated, been relaid in many places three times with steel rails since it opened five years ago. Not content with this rate of destruction to road and stock, the Metropolitan Company are now receiving, or about to receive, locomotive engines of a still more destructive character to work the St. John’s-wood branch, weighing 45 tons on 6 wheels, with a wheel base of 14 feet. The only approach to a saving feature in the 42 ton engines—viz., carrying the leading end of the engine on a bissel truck with four wheels—is in these new engines omitted. The bissel arrangement does to some extent reduce the enormous friction of the engines on rounding the curves, notwithstanding which the grating and grinding noise of the wheels can be heard at a considerable distance. The spirit of rivalry between armour plates and guns is reproduced in steel rails and locomotive engines, with this difference, that the armour plates can be made to withstand the power of the heaviest guns, whilst steel rails cannot -withstand the battering of these 45-ton steam hammer locomotive engines. The destructive element of the ordinary type of locomotive is so vital, and affects the question of shareholders’ dividends so much, that I would fain trespass on the time of the meeting to show how this results. The superstructure or principal weight of a locomotive engine borne on six wheels is supported on six points close to and inside each wheel. Between these supports and the wheel the carrying springs are placed. Now a very heavy engine with a great amount of overhang must, from the imperfections of the road, rock about a great deal, and the centre of gravity of the engine, instead of moving forward in a straight line, as it should do if the line and everything con nected with it were perfect, forms a continuous line of curves and reverse curves on each side of the line of direction, as re presented in Fig. 4. Fig. 4. Showing the lino traversed by the centre of gravity to each side of centre line of motion through the deflecting action of the springs This is caused at first by some defect or slight obstruction in the road, and afterwards kept up by the springs receiving and deflecting with the force of the up-and-down movement of the great body of weight resting on them, as shown in Fig. 5. Fig. 5. T Showing the lateral movement of the centre of gravity to each side of the cen tre line of motion caused by the vertical action of the springs; showing also the deflecting action of the spring, and how it affects the centre of gravity ; caused by an imperfect permanent way. This action of the springs is caused by the oscillation of the centre of gravity to either side of the centre line of motion (see Fig. 5), and then easing themselves by flinging the weight from one to the other, either diagonal to, or at right angles with, the line of motion, and so repeated until the oscillations are gra dually diminished ; but it is found in practice that the oscilla tions never cease, for before one set is completely reduced an other commences, keeping up a constant surging or soughing from side to side during the entire journey. The exact force of impact'on the rail caused in this manner is represented by the amount of deflection of each spring beyond its normal condition. We shall be well within the mark by saying the destructive effect to the rail is over 60 per cent, more than the normal load on the wheels. Thus, in the case of the 45-ton Metropolitan, engines it is not simply this weight divided over six wheels, but a concussion of 60 per cent, in addition, or between 11 and 12 tons blow on the rails. Herein we find the explanation of the frequent necessity for the renewal of the rails. It is often argued that, because the additional load is received, taken up, and afterwards thrown off by each spring, the damaging effect on the rails is very little beyond that of the normal load, but I submit that this is not so. On the contrary, whatever extra 20