. The Street railway journal . cases to besquare and straight, with sharp or slightlybeveled edges. Their specific gravity mustnot be less than , and they must not absorbmore than 3 per cent of their weight ofwater after an immersion of two days. Thebricks are laid (see section) upon a cushionof sand resting upon concrete foundation is formed of concrete com-posed of one part Portland cement, four parts sand andeight parts crushed stone or clean screened gravel. Thefoundation is 5 ins. in depth, extending from the under to theupper surface of the ties. In placing this concre
. The Street railway journal . cases to besquare and straight, with sharp or slightlybeveled edges. Their specific gravity mustnot be less than , and they must not absorbmore than 3 per cent of their weight ofwater after an immersion of two days. Thebricks are laid (see section) upon a cushionof sand resting upon concrete foundation is formed of concrete com-posed of one part Portland cement, four parts sand andeight parts crushed stone or clean screened gravel. Thefoundation is 5 ins. in depth, extending from the under to theupper surface of the ties. In placing this concrete, the follow-ing method was adopted: Concrete was mixed by hand, a gangof sixteen men being employed, of which six wheeled the ma-terial to the mixing board, where four gave it a preliminarymixing. It was then thrown into a McKelvey mixer, wherewater was added to the proper consistency. The mixer, drivenby a gasoline engine and mounted upon wheels, could be movedalong the track, so that the concrete was deposited practically. ONE TRACK GIVEN FIRST LIFT, OTHER UNBALLASTED where wanted and spread with hoes. Upon this bed is spread1 in. of mortar, consisting of one part Portland cement andfour parts sand. Four men were used to mix and spread theneat cement. The mortar was applied before the concrete wasset, so as to form a perfect bond. The cushion bed is laid onthe concrete foundation after the concrete has become thor- December 16, 1905.] STREET RAILWAY JOURNAL. 1051 oughly set and dried, and consists of a J^-in. layer of clean,coarse, sharp sand. Along the inside of each rail there isplaced a brick of special design, which forms a groove orflangeway for the wheels of the cars. The construction on sharp curves around street corners con-sists of the center rail laid without groove and the inner railwith machine-fitted guard rail. The rail is 90-lb. A. S. C. E. OVERHEAD CONSTRUCTIONIn view of the heavy and permanent standards adopted inthe overhead work, it is believed that a so
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
