. The Street railway journal . r below it thepounds of coal burned during the sameperiods. If the station efficiency is constant,that is, if the same number of pounds of coalare burned to produce a kilowatt-houreach week, the kilowatt-hour line and the pounds of coalline, if plotted, one above the other, will remain the samedistance apart, although each will have fluctuations depend-ing upon the output. If, however, through the use of aninferior quality of coal, or from some other cause, the sta-tion production becomes less efficient, the result is instantlyshown by the coal line approaching c
. The Street railway journal . r below it thepounds of coal burned during the sameperiods. If the station efficiency is constant,that is, if the same number of pounds of coalare burned to produce a kilowatt-houreach week, the kilowatt-hour line and the pounds of coalline, if plotted, one above the other, will remain the samedistance apart, although each will have fluctuations depend-ing upon the output. If, however, through the use of aninferior quality of coal, or from some other cause, the sta-tion production becomes less efficient, the result is instantlyshown by the coal line approaching closer to the kilowatt-hour line if it is below the latter, or departing from it, if it is the upper line. This change in direction instantly pointsa moral which would be equally shown, of course, by atable, but would not be so visually evident. If we wish tocarry the work still farther, other lines can be added to thesame chart, or drawn separately to show car miles run,passengers carried, etc., and each will point its FIG. Distance (Miles) from City Hall. Str*t IUUww Journal 2. — METHOD OF GRAPHICALLY ILLUSTRATING VARIOUS RATES OF SPEED For instance, if the kilowatt-hour line plotted by weeks ormonths is below the car mile line and approaches it, itdiscloses the fact that more power is being taken per carmile than formerly. If the cars are of the same size andcarry practically the same loads at the same speed, theinference is that there is some difficulty in the transmissionsystem, and an investigation of the rail-bonds, overheadline or car equipments is in order. November i, 1902.] STREET RAILWAY JOURNAL. 743 This method can be applied to any system of variablequantities. In the case of an electric light station, it wouldbe but necessary to reduce it to a kilowatt hour basis, andevery quantity entering into the cost of the operation ofsuch a station can be applied by using time as abscissae andcost as ordinates, and any variation in such quantitiesreadily and strik
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
