THE RIVALS OF THE STEAMENGINE.

Globe, Volume XXIV, Issue 2503, 15 April 1882, Page 4

THE RIVALS OF THE STEAMENGINE.

Long before the dream of the British farmer is realised and the only rabbit in the country is a stuffed specimen in tho British Museum, that vast depository of antiquities will bo the only place where the curious will be able to see a looomoiive steam-engine. So, at least, said the seers of science at tho last meeting of tho British Association, and their prediction has sat men thinking as to what will take its place. Steam has superseded horses. What will supersede steam ? Compressed air or electricity ? Without attemptins to solve the enigmas of the future, it will be more profitable to notice the progress that is being made in the present by the rivals of the steam-engine. On the railway the locomotive has as yet an absolute monopoly. On the tramway it has to struggle for its existence on an equal footing with its three rivals—electricity, air, and horse power. At present the horses have it almost all their own way ; but there are many signs that their day is drawing to a close. For the quantity of fuel supplied—in the shape of oats—the horse generates more mechanical energy than any inanimate machine ; but oats are dearer than coal, and the horse wears out faster than an engine. The cost of the keep of a tramwayhorse varies from the minimum of |£24, which is touched at Birmingham, to from £34 to £42, between which tho cost of its keep varies in London and other large towns. Tho average life oi a tram horse is only four or four and a half years. On the North Metropolitan tramways, out of a stud of 2000 horses, eighty die every year, and sixly or seventy are sold as unserviceable, while there are usually about thirty sick or lame. The annual loss on horses on this line alone averages £6OOO, without reckoning the necessity of keeping up a horserenewal reserve account of £25 000. Apart from all considerations of humanity, the question of economy leads tramway companies to look out anxiously for any feasible method of replacing the costly and perishable motor which they at present employ by some mechanical contrivance which shall be at once cheap, safe, and simple, and not absolutely intolerable to the general public. It is the last consideration which hitherto has been fatal to the use of steam on most tramways. Seme noiseless tramcar engines have been invented, and they expect to use one on the new tramway which is being laid down at Darlington, but they do not seem to have met with general acceptance; while as for the. noisy, clanking, snorting locomotives which ply from Courbevoie past the Arc de I’Etoile on the Northern Tramway of Paris, any one who introduced such motors in this country would deserve summary execution without benefit of clergy. The utilisation of electricity on tramways is as yet a dream of the electrical engineer. It is a proved possibility, as witness the electrical tramcar which plies daily to and from the suburbs of Berlin ; but it is not a practical possibility, on the ground of expense. The Berlin experiment is little more than an advertisement, and, judged as such, it is undoubtedly very successful. But electricity as a motor has not come within practical reach of the economical tramway manager with his fixed maximum of so much per tram mile. In time no doubt the storage of electricity may be so perfected as to render it practicable to drive oars by lightning, but at present it is out of reach. When the current must be transmitted in a continuous current from the generating centre, the risk of disconnection is too great to permit of its regular use in crowded thoroughfares. A car has been run on this plan at the Crystal Palace, and a large car driven by electricity was one of the attractions of the Electrical Exhibition at Paris. But as the latter, which could easily have been drawn by two horses, was worked by a 25-horse power engine, it afforded no test as to the comparative value of the rival motors. Leaving on one side the pneumatic eyetem as not applicable to tramways, and dismissing the plan of haulage by an endless chain which is in use at San Francisco, and which it is proposed to introduce at Haveretockhill, Pentonville, and other hilly districts in London, there is nothing left but compressed air. There seems good reason to believe that if this is not the motor of the future, it is certain to play a prominent part in the struggle for existence between the rival motors which is destined to result in the supersession of the eteam engine. The other day we called attention to the fact that the Board of Works had consented to a t.ial of the Mekarski air engine in tho Caledonian road, over the tramway of the London Street Company, From inquiries made at the office of the Company, we learn that it is not intended to begin the trial at once. The consent of the Board of Works is only granted for throe months, and the licence of the Board of Trade is still to be obtained. They intend to wait till summer, when their traffic is at its best, before starting the Automobile car. The Caledonian road way, which is about one and threequarter miles long, is to be selected for the experiment because it is least frequented by other traffic. If it succeeds, it will probably be adopted on o large scale. Hitherto it has only been tried once in this country, namely, on the tramway which connects Wantage, in Berkshire, with the Great Western Bailway, where it gave very satisfactory result*. The most exhaustive trial of the Mekarski system, however, is that to which it has been subjected in Nantes, where all the traffic on tramways four miles in length has been carried on by means of twenty-two Mekarski cars, starting every ten minutes from each end, from fourteen to fifteen hours a day. The oar weighs six tons, and carries nineteen passengers seated and twelve standing. The ten cylindrical reservoirs of steel which hold the compressed air are placed transversely below the floor of tho car. The air is passed through a reservoir of hot water and steam carried in front of the car, thereby expanding the air and preventing the formation of ioe in the exhaust passages of the cylinders. The cylinders are charged with compressed air and the reservoir reheated by steam to a temperature of 320 deg. at the beginning of each journey. The process takes from six to ten minutes. The cars are driven at an average speed, including stoppages, at from five to six miles an hoar, and the air brake pulls them up within two or three yards. There is no smoke, no chimney, no machinery visible. They run on an average 750 miles a day in Nantes, by a consumption of four and a half tons of coal.

While the Loudon Street Tramways Company are about to place the Mckarski engine on the Caledonian road, the North Metropolitan Tramway Company have decided to try the Beaumont engine, which has been tried very successfully between Stratford and Leytonstone, The Beaumont differs from the Mekarski both in the pressure and in the mode employed for warming the air. In the Mekarski the air is compressed to 4501 b on the square inch ; in the Beaumont the pressure is 10001 b, and by applying the necessary warmth by external steam jacketing the air is admitted direct to the working cylinders, instead of being passed through the reservoir as in the Mckarski, by which, according to its advocates, the Beaumont engine saves two-thirds of the energy wested in reducing the pressure in its competitor, The Beaumont engine was tried last year on the Underground Railway, when it took a train weighing twenty to thirty tons from Moorgate street to South Kensington, keeping proper time and stopping at all the stations. The cost of working would be about the same, whether air or steam is used, but the former offers such advantages in the way of ventilation that its adoption can only be a matter of time. The expense of converting the existing locomotives into air engines is however the great obstacle in the way of a change from which the public would reap unmized benefit. In the utilisation and transmission of natural forces, such as winds, tides, waterfalls, &0., air and electricity offer almost eqtal advantages. A tube in the one case, a cable in the other, may yet suffice to transmit the accumulated energy of a cataract to drive the street cars of a capital.—“ Pall Mall.”