. Railway mechanical engineer . ar that the one electriclocomotive is nearly equivalent to the two steam locomotives. •The U. S. R. .\- standard heavy Mountain type. Masch. 1919 RAILWAY MECHANICAL ENGINEER 135 It must be remembered that the two steam locomotives couldmaintain this speed continuously with a tractive effort of80,000 lb., while the electric locomotive could not on accountof the electric motors requiring a current much above thecontinuous rating. Since horsepower is such an important factor, Fig. 2 hasbeen drawn, showing the relative horsepower for the twoengines chosen. Here the
. Railway mechanical engineer . ar that the one electriclocomotive is nearly equivalent to the two steam locomotives. •The U. S. R. .\- standard heavy Mountain type. Masch. 1919 RAILWAY MECHANICAL ENGINEER 135 It must be remembered that the two steam locomotives couldmaintain this speed continuously with a tractive effort of80,000 lb., while the electric locomotive could not on accountof the electric motors requiring a current much above thecontinuous rating. Since horsepower is such an important factor, Fig. 2 hasbeen drawn, showing the relative horsepower for the twoengines chosen. Here the comparison is even more striking,and the great advantage of the electric locomotive is easilyrecognized. This electric locomotive of the same weight asthe steam, has a maximum developed hp. rating at the rimsof the drivers of 5,860 hp. compared to 2,825 hp. for thesteam locomotive. And when compared with two steamlocomotives it shows, for the working range, the ability todeliver the equivalent in hp. Of course, the continuous. soo 1200 Z500 3000 SSOO 1500 2000 Am pe res~Fig. 3—Characteristic Curves for 266-Ton Electric Locomotive rating must not be lost sight of, and for the electric loco-motive this is 3,200 hp. The increase in horsepower isdue to the increased speed for the same tractive effort. Re-ferring to Fig. 1, assume there is a passenger train requiringat certain sections or grades, a tractive effort var)ing from50,000 lb. to 40,000 lb. At 50,000 lb., the speed of thesteam locomotive w-ould be I6J/2 miles per hour—the electric,29 miles per hour—nearly double. At 40,000 lb., the steam Comparison of and Electric Locomotives of Equivalent Weights Characteristics Steam Electric 4-8-2 4-6-2—2-6-4 Weight—engine and 14-ton tender tons 266 tons Weight—engine only 353,000 lb. 532,000 lb. Weight—engine on drivers 243,000 lb. lb. Number of pairs of drivers 4 6 \\eight per pair 60,500 lb. 55,000 1b. Wheel diameter, inches 69 , °?-, . Total whe
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
