. American engineer and railroad journal . in the calculation this irregularity has beendisregarded. The reaction of the portion of the load beyond the bolsters isgraphically shown by an opposing figure of equivalent area andapproximately similar form, which cuts off a large portion ofthe weight in the first panel of the truss, which would other-wise be distributed between the bolster and the first intermedi-ate post. It will be noted that the strains in the posts andbraces of this car are opposite in effect as compared with thoseof the 40-ton gondola car, Class GG, the latter being a six-pane
. American engineer and railroad journal . in the calculation this irregularity has beendisregarded. The reaction of the portion of the load beyond the bolsters isgraphically shown by an opposing figure of equivalent area andapproximately similar form, which cuts off a large portion ofthe weight in the first panel of the truss, which would other-wise be distributed between the bolster and the first intermedi-ate post. It will be noted that the strains in the posts andbraces of this car are opposite in effect as compared with thoseof the 40-ton gondola car, Class GG, the latter being a six-paneltruss. The good effect of narrowing the center panel of the trussmay also be seen. The stresses will be noted as extremely lowfor the cross-section of the posts and braces used, but the ques-tion of lateral strength is one that enters largely into car de-sign, and in this case was an important factor. A special sec-tion could be designed to use greater economy of steel, but spe FfcBRUARY, 1901. AMERICAN ENGINEER AND RAILROAD JOURNAL. 48. >*#; / i* -?7-— -—i Showing Construction of Bolster. cial sections and odd sizes of material were considered very un-desirable. The weight of the car is very satisfactory, notwith-standing tliis, weighing but 38,000 lbs., new, to carry over 74 peicent, revenue load. The test load of 112,000 lbs. produced avertical deflection of but Vs in. at the center of the sides, meas-ured between the bolsters, while the deflection of the centersills was 7/32 in. The specifications of these cars are in the usual form, and inelude sections relative to the punching, rivets, etc., that arein conformity with those of the Manufacturers StandardSpecifications. The following is quoted as the language of thespecification in regard to the painting of the steel frame and ofthe completed car: Before riveting up all surfaces coming together shall bepainted, and after the frames are riveted up and before anywoodwork is attached they shall be cleaned and thoroughl
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
