The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . ethin plates of sheet steel are bent into the oval holes in the yokesextending from yoke to yoke, and form the inner surface of thecompleted conduit. Around this is carefully laid a shell, 4 in. thick,of Portland cement concrete. The yokes are furnished with lugswhich serve to retain, temporarily, wooden boards forming a mouldin which the concrete is rammed. Sectional wooden shapes serveto hold the thin steel lining in place while the concrete is this concrete tube, and on each si
The encyclopædia britannica; a dictionary of arts, sciences, literature and general information . ethin plates of sheet steel are bent into the oval holes in the yokesextending from yoke to yoke, and form the inner surface of thecompleted conduit. Around this is carefully laid a shell, 4 in. thick,of Portland cement concrete. The yokes are furnished with lugswhich serve to retain, temporarily, wooden boards forming a mouldin which the concrete is rammed. Sectional wooden shapes serveto hold the thin steel lining in place while the concrete is this concrete tube, and on each side of it, to form a basisfor the street pavement, is laid a mass of coarser concrete. In eachside of the special yokes is placed an insulator of porcelain, protectedby a cast-iron shell and carrying a support for the conductor rail,which is of T-shaped steel, weighing 21 tb per yard. It is in 30 and is supported every 15 ft. by the insulators, the ends ofseparate rails being matched at and held by an insulator rail is, of courSe, bonded with copper bonds. Two such con-. TTTTTT/ Fig. 8.—Cross-section of Open Conduit Road (American type). ductor rails are installed in the conduit 6 in. apart, the flat facescorresponding to the upper surface of the T being placed towardseach other. Elaborate provisions for drainage and inspection arealso provided, depending upon the situation of the tracks and natureof the street. The current is fed to the conductor rails by heavycopper conductors of from to 1,000,000 circular mils cross-section, insulated and lead-covered, laid in ducts alongside of orbetween the two tracks of double-track systems. Connexion is
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
