. Elements of railroad track and construction . handle. They are laidin the same manner as vitrified pipes, and the same dis-cussion applies to the joints, except that cast-iron pipewith cemented joints is more liable to break in case ofthe foundation settling, on account of its greater length. 367. End Walls for Pipe Culverts.—In pipe culverts,either vitrified or cast-iron, the ends must be protectedby masonry so that the pipe is held firmly in place andwater cannot enter and seep through the fill along theoutside of the pipe. The masonry may be stone, brick, I 350 RAILROAD TRACK AND CONSTRUC
. Elements of railroad track and construction . handle. They are laidin the same manner as vitrified pipes, and the same dis-cussion applies to the joints, except that cast-iron pipewith cemented joints is more liable to break in case ofthe foundation settling, on account of its greater length. 367. End Walls for Pipe Culverts.—In pipe culverts,either vitrified or cast-iron, the ends must be protectedby masonry so that the pipe is held firmly in place andwater cannot enter and seep through the fill along theoutside of the pipe. The masonry may be stone, brick, I 350 RAILROAD TRACK AND CONSTRUCTION. or concrete, may have a plain vertical face, or may havewing walls when the pipe is large. The simplest formof end wall is shown in Fig. 190, being a rectangular wallof concrete. The foundation must be at least two feetdeep in order to be below the frost line. The other di-mensions will depend upon the size of the pipe and theheight of the embankment to be retained. A culvert 24inches or less in diameter will not need a more elaborate. Fig. 190. arrangement than that shown in Fig. 190, but a culvert30 inches or more in diameter may need wing walls, anapron wall, and a paved entrance, in some cases. Asend walls for pipe culverts are usually neither high, wide,nor deep, it is more convenient to build them of concreteor brick, unless suitable stone is found close at hand andcheaper. In some cases, owing to scarcity of materialand there being little danger of the culvert being injuredin the meantime, the end walls are not built immediately, CULVERTS. 351 in which cases the materials may be delivered after thetrack is laid, thus reducing the cost. 368. Timber Box Culverts.—In country where tim-ber is plentiful and stone or pipe hard to obtain, cul-verts are sometimes built of timber. They are builtlarge enough to allow the permanent structure to bebuilt or placed inside of them, so that it will not benecessary to cut a trench through the Fig. 191 is shown the
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcetc, bookyear191
