. Locomotive engineering : a practical journal of railway motive power and rolling stock . e comeout. These are 6 x 10 inches, but they arenot all bearing surface, as is the case withthe driving box. The usual form is to putin two babbitt strips about l^ inches wide projected area or on the accepted load persquare inch. Car brasses, however, generally bear onthe whole surface, and in those which aremade on the square of the axle theoryhave a larger projected area. In the caseof a 50-ton coal car we have a dead weightof 30,000 pounds, or a total of 130,000pounds, or 16,250 on a bearing. Allowin
. Locomotive engineering : a practical journal of railway motive power and rolling stock . e comeout. These are 6 x 10 inches, but they arenot all bearing surface, as is the case withthe driving box. The usual form is to putin two babbitt strips about l^ inches wide projected area or on the accepted load persquare inch. Car brasses, however, generally bear onthe whole surface, and in those which aremade on the square of the axle theoryhave a larger projected area. In the caseof a 50-ton coal car we have a dead weightof 30,000 pounds, or a total of 130,000pounds, or 16,250 on a bearing. Allowinga bearing of 9 by 4;^ inches, which is con-sidered ample, there is a projected area square inches. Dividing 16,250 , there is about 425 pounds per squareinch. The service is very similar to thatof a truck, the same tendency to roll outof a bearing when brake is applied (whichis one reason for dropping the strips downon the side in the case shown), and itwould seem as though the same bearingwould give as good service in one case asin the other. There are several sides to. and the same distance apart, as shown inFig. I. This gives a projected area oi 1%inches by the length (10 inches) in eachstrip, or 11% square inches. The twostrips give 22j^ square inches to carry10,000 pounds, as there are 20,000 poundson the truck. Dividing 10,000 by 22>4gives pounds per square inch of pro-jected area, or double that of the driving-box journal. Taking the case of some roads who placethe strips farther apart, we have an en-tirely different case. Fig. 2 shows thebearing that is being used by one road,with the strips all of 4 inches apart. Aswill be seen, the projected area of eachstrip is but % inch wide, or 6]4 squareinches. The entire bearing is only inches. With the same load as be-fore, 10,000 pounds on a wheel, we have10,000 divided by , or 800 pounds tothe square inch. Yet they run cool as longas the strips take the load. When thestrips wear down, s
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroa, bookyear1892
