. The Street railway journal . ows where the pole is 30 ft. long and placed 6 ft. in theground: Round bottom. Top. Deflection. Chestnut. Cedar 10% in. 5% in. 7 in. 340 lbs. to 510 lbs. 360 lbs. to 406 lbs 11% in. 6% in. 7 in. 405 lbs. to 680 lbs. 432 lbs. to 540 lbs 12% in. 7% in. 7 in. 490 lbs. to 935 lbs. 495 lbs. to 675 lbs! The above was the average of a number of experiments. CROSS ARMS, SIDE ARMS AND BRACKETS The standard cross arms usually kept in stock are givenin Fig. 3, with the dimensions and spacing for pinsCross arms are usually kept in white or Norway pine orlong leaf yellow pine
. The Street railway journal . ows where the pole is 30 ft. long and placed 6 ft. in theground: Round bottom. Top. Deflection. Chestnut. Cedar 10% in. 5% in. 7 in. 340 lbs. to 510 lbs. 360 lbs. to 406 lbs 11% in. 6% in. 7 in. 405 lbs. to 680 lbs. 432 lbs. to 540 lbs 12% in. 7% in. 7 in. 490 lbs. to 935 lbs. 495 lbs. to 675 lbs! The above was the average of a number of experiments. CROSS ARMS, SIDE ARMS AND BRACKETS The standard cross arms usually kept in stock are givenin Fig. 3, with the dimensions and spacing for pinsCross arms are usually kept in white or Norway pine orlong leaf yellow pine. The tensile strength of Norwaypine is approximately 10,700 lbs. to the sq. in., and thebreaking cross load for long leaf yellow pine is 21,300 sq. in. The breaking cross load for the standard sizeof cross arm is 5060 lbs. for white pine and 3820 lbs. foryellow pine. Records show that the long leaf pine is 40per cent stronger, but the yellow is more durable, as itdoes not rot so readily where the iron bolts pierce the. FIG. 4.—CROSS ARMS, SIDE ARMS AND SPECIAL METHODS cross arm, which is the point at which the cross arm has tobear the greatest strain. In order to avoid pierqing thewood at this point with wood poles and also where woodencross arms are used on iron poles, straps and plates arcemployed, as shown in 2, Fig. 3. The pole is gained inthe regular way when wooden, but where the pole is irona saddle is cut into the cross arm to make it fit the poleand thus increase the bearing area of the cross arm. A, Fig. 3, shows a cast-iron fitting to attach a woodencross arm to an iron pole. For securing cross arms to polesin railroad feeder work use f-in. bolts or 5-in. lag cross arms should be planed straight grained andpainted with two coats of Princes metallic paint, made upin the proportions of 7 lbs. to 1 gal. of pure linseed oil. Three designs of split cast iron brackets are shown in4, 5 and 6, Fig. 3. The two halves clamp the pole by twobolts which
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
