A Railway Revolution. NEW DEVELOPMENT IN ECONOMICAL HAULAGE.

"We are on the eve of a mechanical revolution such as has never been Been since the introduction of steam." This startling statement (says The Times) was made at the animal dinner of the Leeds Association.' of Engineers on Bth December by Mf. H. S. Oautley, M.P., who, in making the announcement, "raid that he did so because of what Alderman Wigram had told him ho had investigated as chairman of the Locomotive Committee of the Great Northern Kailway directorate. In engineering circles great curiosity has been aroused by such sweeping statements made by persons competent to judge. It seems Alderman Wigr&m was of opinion that detailed information might be withheld till the forthcoming meeting of the Great Northern shareholders, for, though he spoke after Mr. Cautley, he did not. refer to the matter. But since the invention is of world-wide importance, and was not made on or by the Great Northern Railway, there need be no hesitation in satisfying public cariosity on the part of one who has personally investigated the series of important experiments and trials made on that railway under the direction of Mr. Wigram and Mr. H. A. Ivatt (the locomotive superintendent) during the'popt year, and who has been on the locomotive at some of the most crucial of them. Mr. J. T. Marshall, a Leeds engineer, has invented a novel valve gear, which, since it involves no alteration on a loco- 1 motive beyond its own substitution for «omo part of tho present valve gear, con be fitted at small cost, with the result that, with a lower steam pressure, the haulage power is greatly augmented, and ttto coal consumption, if not reduced, at least not increased. In order to put the invention to a practical test the Great Northern Railway, had it fitted to an old mineral locomotive, built in 1882 by Messm. Dubs and Co., of Glasgow, with a very small boiler having under 1000 square feet of heating surface, 17i}in by 2oin cylinders, six driving wheels of sft in diameter, and weighing (with the tender) about 70 tons. This engirre— No. 743-— was pitted in a series' of trials, in the same work, day after day, against a sister engine of the same pattern, but having the old valve gear. These trials began about nine months ago. The results exceeded all expectations. On the first trip, on 2nd May, No. 743 took a load of 279 tons 15cwfc up an incline of 1 in 71£, tho ste;«n pressure never being higher than 1401 b per square inch. This load is nearly 80 per cent, greater than that booked to be taken by this class of locomotive at this point. On 6th May, on the same bank, the load was maao up to no fewer than 307 tons, with which the locomotive successfully coped. On the next day she was tested qn the wellknown Wrenthorpe to Burkinshaw section, famous for its very bnd banks, which vttYy from 1 in 40 to 1 in 100, the load being increased above the standard by one-half, - again With excellent results. On 9th and 10th May careful trials were made between the two sister engines on the section between Lofthouse and City-road, Bradford, in order to get statistics of the comparative coal consumption. Tha non-converted engine used about 20cwt of coal, or. 721 b per mile, while No. 743 used only llcwl, or about 391 b per mile, in spite of the fact that on the return journey she wns saddled with a heavier load than her sister From 13th to 18th Mny the coal consumption trials were continued, each engine doing three days' work of an identical character, the average giving a return of '57,71 b per mile for the ordinary locomotive, whilo No. 743, with the new valve gear, came out at 46.21 b per mile — a figure which does not give the true economy, since the experiments were vitiated by some one who, objecting to novelties, one night, under cover of dnrkness, put the wagon brakes on tho train. In spite of this the engine dragged the tvnin at speed so far that the mischief was discovered by many of the brake blocks getting fired. From 20th 1

to 25th May the competition was con- ' tinued, No. 743 being handicapped by being made to drag 33 to 50 per cent, greater loads, the figures showing that the ordinary engine consumed about 671 b of coal per mile, while No. 743, with these much greater loads, used only 631 b per mile. Kin.cc 28th May No. 743 has been running from Doncastet to Peterborough^ taking from 30 to 45 wagons of coal, returning on the "express goods" with 32 wagons rtnd upwards, tho average* working out at about 99 extra wagons taken per week of five days, with a reduced coal consumption. When the loads wero equal a, saving was effected of at least 81b to 91b per mile ovof* her sister locomotives. Th» steam pressure was kept at fully 201 b below the usual one for this old class of locomotive — a point the importance of which will be realised by any one who knows the expenses attendant on p. high-pressure boiler. # The valve gear keeps absolutely cool, and shows little or no sign of wear so far, while t"he marked absence of shock is beneficial both to cylinders and to reciprocating parts. It js impossible, to set out at length the elaborate statistics compilea in these months of trials, or to discuss the technical questions investigated on the footplate by the writer. But "seeing is believing," and this old locomotive performed the feats mentioned without any fuss. A £ood deal of nonsense has been written m the press, and statements curious in their ignorance have been made at meetings of locomotive-drivers, touching the sad explosion of a Lancashire and Yorkshire railway engine at Knottingly, as if 2201 b to the inch were a dangerously high pressure, whereas 2101 b, 2151 b, 2231 b, and 2281 b have long been commdn in France and the United Suites, and eminent men in these countries will shortly look for 2501 b. Still, no one favours high pressures if he can get the work economically done at lower ones, since the- higher the steam pressure tho greater the wear and tear, and also the greater chance of ' an explosion ■ from some defect in work or material. The new valve geur causes the steam to be so excellent!/ passed in and out of the cyliuders that 30 to 60 per cent, more ' haulage power is provided with lesi'fuel consumption, and with a steam pressure j some 301 b lower than modern practice. Back pressure is markedly reduced. Lawyers, farmers, and * mechanical engineers are busy with the spark-throwing problem. No. 743, as fitted with the new valve gear, seems to have solved this problem, for, whether "bursting herself" (as they say) with a heavy load, or. running "fast goods" at 40 miles an hour, tho blast is peculiarly long-drawn and soft. It is very uulike that firedestroying and tube-choking, hard, sharp, and pyrotechnical sort of blast which we are used to in this country, and which in tho United States may be seen and heard from a great way off. Since the Marshall valve gear can be quickly adopted on. any locomotive it s,eems clear that old engines, about to 'bo condemned only because thoy are too small, may take a new lease of life, in which they will he ab!o to do work never done before.- The Wreat Northern »Js now fitting the, new valve gear on a number of express engines which will shortly be 'running be« tweeu London and York, on thoir portion of tho Knst Const route. One may safely predict that this valve gear will work a revolution in marine engines also, both an to augmented power and as to lessened fuel consumption, and arrangements are now beinj( made to fit the valve gear on the engines of a vessel of one of the largest shipowning firms in Great Britain. A very important colliery in England has nlso adopted tho Marshall gear for its winding engines. The directors of the Great Northern Railway, and especially their locomotive superintendent, aro to be congratulated ns the pionoers in the adoption and practical testing of this new development in mechanical engineering, which bidH ( ! fair to provide the railways withya great I means of saving in the hauling of their traffic. i

No. 1 : "How did Diok gat run over?" No. 2: "He was picking up a hor'rfeshoe for luck."