. Railway mechanical engineer . with long cut-off locomotives as to economy in coal and steam, haveyielded expected results. The tests have shown that therestricting of the cut-off has had the desired effect in that,in full gear, where the bulk of the work is done, this locomo-tive operates much more economically than the Lis. Thisadvantage, as e-\pected, is reduced as the engines are cutback, but it is not until we have gone below the most econom-ical cut-off for both locomotives that the Lis and lis showthe same economy at a given horsepower. This, moreover, isthe case only at the low-er hor
. Railway mechanical engineer . with long cut-off locomotives as to economy in coal and steam, haveyielded expected results. The tests have shown that therestricting of the cut-off has had the desired effect in that,in full gear, where the bulk of the work is done, this locomo-tive operates much more economically than the Lis. Thisadvantage, as e-\pected, is reduced as the engines are cutback, but it is not until we have gone below the most econom-ical cut-off for both locomotives that the Lis and lis showthe same economy at a given horsepower. This, moreover, isthe case only at the low-er horsepower (in short cut-offs atlow speeds), that is, for but a small portion of the work doneby the locomotive when in normal railroad service. Indicator Diagrams and Action of Starting Ports.—Repre-sentative indicator diagrams are shown in Fig. 2. The prin-cipal point of interest in these diagrams is the action ofthe auxiliary starting port. It opens before the openmg ofthe main port, having a lead of 1 15/16 in. in the tests. /6 la zo ZZ 24 Z& Z8 JOSfeam Per Indicated HorseponerHour. Pounds. Fig. 8. Piston Speed and Water Rate kere recorded, as against 3/16 in. for the main port and, onthe indicator diagrams, the effect caused thereby canscarcely be noticed. Considering the cards for fullgear, there is no evidence that the auxiliary ports admita sufficient amount of steam to hold up the admission lineappreciably, after the cut-off of the main port. The Testingplant conditions in starting are not the same as on the road,on account of there being little or no resistance to turningthe locomotive wheels and no rolling load, in the form of thelocomotive itself and the train. Indicated Horsepower.—The test results in indicatedhorsepower are plotted on Fig. 3. The range of horse-power was between and 3, The highest powerwas obtained at a speed of 140 , which is equivalentto The superheated steam used per hour was and lb. In 12 o
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
