. Railway mechanical engineer . 0. It was found that with a tibre stress of 14,000 lb. per sq. in., the sectionmoduli at the center of the bolster were , for the three side bearing spacings as compared by the formula in which a 12,500 lb. stress was reaction for the subjected to the combined action)f a direct center plate load of 7,5,000 lb. and a horizontalforce equal in amount to of this load and whose sidebearings have a spread of SO in. is equal to 221 per centof the normal reaction which is practically equivalent tothe 220 per cent suggest
. Railway mechanical engineer . 0. It was found that with a tibre stress of 14,000 lb. per sq. in., the sectionmoduli at the center of the bolster were , for the three side bearing spacings as compared by the formula in which a 12,500 lb. stress was reaction for the subjected to the combined action)f a direct center plate load of 7,5,000 lb. and a horizontalforce equal in amount to of this load and whose sidebearings have a spread of SO in. is equal to 221 per centof the normal reaction which is practically equivalent tothe 220 per cent suggested by Prof. Endsley, and as it isour understanding that the side bearings on tiie hopper carused in the experiments conducted by Prof. Endsley werespaced 50 in. apart or the same as one of our assumedspacings, we have plotted the diagrams of Fig. 10, for afibre stress of lb. since the resulting values for thesection moduli, for the bol.^ters having the same side bear-ing spacing, check with the formula shown in the upper. posed IVIethod of Testing Bolsters part of the figure. Based upon a fibre stress of 16,000 sq. in., values for section moduli at the center of thebolster, as Fig. 5, are , and , respectively,which of course, are slightly less than those for the 14,000lb. fibre stress. M the side bearings for the 16,000 , we obtain the values of , , and , as com-pared to , and by the formula method. Thefact that these values approximate each other very closelyat the side bearings, becomes more evident when the fibrestress is determined from the moments of Fig. 5 and thesection moduli obtained from the formula, the stresses being16,800, 14,650 and 14,000 respectively, for the 50-in., 60-in. and 64-in. spacing. In purchasing truck bolsters, it is the practice of somerailroad companies not to specify the method according towhich the bolsters shall be designed but rather to requirethat the finished bolster shall undergo
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
