. American engineer and railroad journal . nd set ofcurves in Fig. 4 show the variations in torque of a three-cylinderengine, taking the same indicator diagrams as in the two-cylindertype. The cranks are set at 120 degrees, and it will be seen thatthe tractive effort only varies between 85 and 100, with a 3^ percent, cut-off. At 25 per cent, the variation is between 60 and 100,but as the locomotive is then working well within its adhesivelimit, this is of no importance. It is immensely superior to thetwo-cylinder engine in steam economy, as it can be worked,even in mountain service, with at le
. American engineer and railroad journal . nd set ofcurves in Fig. 4 show the variations in torque of a three-cylinderengine, taking the same indicator diagrams as in the two-cylindertype. The cranks are set at 120 degrees, and it will be seen thatthe tractive effort only varies between 85 and 100, with a 3^ percent, cut-off. At 25 per cent, the variation is between 60 and 100,but as the locomotive is then working well within its adhesivelimit, this is of no importance. It is immensely superior to thetwo-cylinder engine in steam economy, as it can be worked,even in mountain service, with at least three expansions, or asput by the author of the paper, The Fairlie or Mallet enginesshould have six cylinders to be equally efficient. The tenor ofthe paper strongly suggests that three-cylinder engines are moreadaptable to heavy grade work, and especially on narrow gaugelines, where the difficulty of designing sufficiently powerful loco-motives is daily becoming greater. It is pointed out that the model n practice of using very large. 20U OF TRAIN TONS FIG. S- boilers is not admissible for heavy gradient working, whereweight must be cut down to the lowest point. Practice showsthat with reasonably good water and coal it is sufficient to allowone square foot of heating surface for every 15 lbs. of availabletractive effort, as worked out by the formula previously Bach emphasizes that great care should be taken in de-sign to keep boiler barrels short and the slope of flue box crownsat least equal to the steepest gradient on which the engines haveto work. For the purpose of determining the grate area required it isnecessary to estimate an engines fuel consumption before com-mencing to design. Working on slight gradients will be but apoor guide, as in heavy gradient working much unconsumedcoal is thrown out of the stack. The author of the paper has adopted a system of estimating areasonable consumption by classing the work done under twoheads, (i) running as on the lev
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
