. American engineer and railroad journal . iformity of the lead. Of these features, that of accessibility is doubtless the mostimportant. The eccentrics of the Stephenson gear of a largefreight locomotive are now so large, and the room in whichto put them is so small, as to render them practically inac-cessible, and they do not receive proper attention, either inthe shop or on the road. As an example of crowding of ec-centrics, the accompanying engraving is presented, by courtesyof the American Locomotive Company, which illustrates oneof the worst cases found necessary in the design of a 2—8—0
. American engineer and railroad journal . iformity of the lead. Of these features, that of accessibility is doubtless the mostimportant. The eccentrics of the Stephenson gear of a largefreight locomotive are now so large, and the room in whichto put them is so small, as to render them practically inac-cessible, and they do not receive proper attention, either inthe shop or on the road. As an example of crowding of ec-centrics, the accompanying engraving is presented, by courtesyof the American Locomotive Company, which illustrates oneof the worst cases found necessary in the design of a 2—8—0type freight locomotive. With a long driving box and eccen-trics 6 ins. wide, there is but 3% ins. of space between themiddle eccentrics on the axle. The rods take up vastly moreroom than the eccentrics, and on examining a modern heavyengine, it is not surprising that men dislike to crawl intosuch a mess on the road, in case of trouble, where pits arenot available. Walschaert gear has been used for many years abroad, and Cot i i i ogi. EXAMPLE up OBOWDKU its development has been carried to a fine point in thedeGlehn compound (see American Engineer, June, 1904). Inis application in this country it will be necessary to secureample bearing surfaces and direct lines of pull and thrust,which are important in every valve gear. The weight is anelement of extreme importance, because of the work whichmust be done at high speed in overcoming the inertia of ordi-nary gears weighing a ton and a half, with frequent reversalsof direction. This is believed to have more effect in causingheating of eccentrics than the work which the gear is requiredto do in moving the valves. In the case of the Lake Shore engine the men like the valvegear, and it appears to be in every way successful. The futureof this gear in this country is not, however, dependent uponthis particular engine. It will be surprising if the gear doesnot become a regular feature of American locomotive practice. Machi
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
