. Railway mechanical engineer . ton, which is a good average forthe usual mixed freight trains with varying weights of carsand loading, when the rolling stock and roadbed are wellmaintained. However, the tonnage can he read from thecharts for any other car resistance factor or any combination TvnLE IâFrictional Resistance of Freight CarsSpeeds 5 to 30 M. P. in tons Resistance { per ton) Loaded Empty Loaded Empty 15 6 20 25 ⢠30 35 40 45 50 55 60 3.
. Railway mechanical engineer . ton, which is a good average forthe usual mixed freight trains with varying weights of carsand loading, when the rolling stock and roadbed are wellmaintained. However, the tonnage can he read from thecharts for any other car resistance factor or any combination TvnLE IâFrictional Resistance of Freight CarsSpeeds 5 to 30 M. P. in tons Resistance { per ton) Loaded Empty Loaded Empty 15 6 20 25 ⢠30 35 40 45 50 55 60 65 70 75 of resistance simply by converting them into terms of grade,using the following multipliers: One pound car resistance = .05 per cent grade. One degree cur\-e uncompensated rr: .04 per cent grade. For example: Find the tonnage of the light Mikadolocomotive on a one per cent grade at a speed of IS ,with a mixed train having a frictional car resistance of four. Tonnage Rating Chart tor the Standard Six-Wheel Switcher pounds per ton; also with a train of 50 tons loaded coalcars, having a resistance of three pounds per ton. From the 2-8-2-A chart at the intersection of the ordinatefor one per cent grade with the drawbar pull curve marked , we find the radial curve reading 1,500 tons. For the train having 50 ton cars with three pound resist-ance, we select the ordinate equal to 1 â [ (4 â 3) x .05] =.95 per cent grade, which at its intersection with curve for18 , reads 1,575 tons approximately. Taking the same example and combining the grade withan eight degree uncomjiensated curve, we have for the mixedtrain, an etjuivalent grade of 1 -|- (8 x .04) = percent, which at 18 gives a rating of about 1,130 tons,and for the train with uniform loads we have an equivalentgrade of 1 -}- (8 x .04) â (1 x .05) = per cent,which at IS gives a rating of approximately 1,180tons. For Pass
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
