. The Street railway journal . becomes a very muchsmaller factor in determining the energy input, especially as thenumber of stops per mile increases. All these three sets of curves are plotted for an acceleratingrate corresponding to 120 lbs. per ton and a braking effort of 150lbs. per ton. The values given will, therefore, be subject to con-siderable variation for different accelerating and braking effortswhere the schedule speed is low and stops numerous. The curvesare, however, of fairly general use, especially for runs of a mile ormore, as the effect of rate of acceleration and braking is
. The Street railway journal . becomes a very muchsmaller factor in determining the energy input, especially as thenumber of stops per mile increases. All these three sets of curves are plotted for an acceleratingrate corresponding to 120 lbs. per ton and a braking effort of 150lbs. per ton. The values given will, therefore, be subject to con-siderable variation for different accelerating and braking effortswhere the schedule speed is low and stops numerous. The curvesare, however, of fairly general use, especially for runs of a mile ormore, as the effect of rate of acceleration and braking is not somarked on longer runs. In Figs. Nos. 12, 13 and 14 is considered, also, a period of coast-ing equaling 10 per cent of the time the train is in motion. Whilethis is a fairly general assumption and will give sufficient marginfor a large majority of problems, it will be found in carrying outthe subject to a conclusion that the per cent of coasting is a verylarge factor in determining the train energy output. For instance,. 0 20 40 60 80 100 120 140 160 180 200 Watt-Houra per Ton-Miie FIG. 14 a high rate of acceleration with a long period of coasting will de-mand less energy input to the train than a lower rate and little orno coasting. The reason for this is obviously that the efficiencyof acceleration of two runs may be approximately 70 per cent,while the speed at which brakes are applied is less with a longercoasting period, and hence the work demanded by the equipmentis less. In all three of the energy curves given a variable friction dur-ing acceleration and coasting is considered, but straight line brak-ing is assumed. The energy required to accelerate the rotatingparts is also considered, so that the curves as given are of fairlygeneral application. In this paper the writer has attempted to outline a methodof determining the probable heating and energy consumption ofa given equipment for any class of work, having in mind, also, thepossibility of arriving at some short
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
