. Railway maintenance engineering, with notes on construction . o3O B > I—I CO m H ;-> CO 2 00/ 64 RAILWAY MAINTENANCE C. Ballast covering from 2 to 4 ins. thick on the ties; a woodfiller being placed between the ties to support the ballast. D. Metal covering on the caps and stringers. E. Metal covering on the ties with 2 ins. of ballast thereon. F. Ordinary pile bridges built with certain kinds of treatedtimber. G. Fire-resisting paints. H. Pile bridges having I-beam stringers. 22. Concrete Trestles.—In railroad construction in the Westand South, it was, and is still quite generally the
. Railway maintenance engineering, with notes on construction . o3O B > I—I CO m H ;-> CO 2 00/ 64 RAILWAY MAINTENANCE C. Ballast covering from 2 to 4 ins. thick on the ties; a woodfiller being placed between the ties to support the ballast. D. Metal covering on the caps and stringers. E. Metal covering on the ties with 2 ins. of ballast thereon. F. Ordinary pile bridges built with certain kinds of treatedtimber. G. Fire-resisting paints. H. Pile bridges having I-beam stringers. 22. Concrete Trestles.—In railroad construction in the Westand South, it was, and is still quite generally the practice to bridgeunimportant streams, bayous and marshes with timber or pile. Fig. 40.—Concrete Trestle. trestles. As the cost of timber increases and as the standardsof the line are raised, these structures have been replaced withmore permanent work. There are, however, many cases in thisterritory of long timber trestles over river bottoms and swampswhere it is not practicable to replace the trestles with morep3rmanent steel bridges on account of their expense. These conditions have apparently been met successfully bythe use of a concrete trestle (Fig. 40) following closely the mainfeatures of the timber trestle, using concrete piles and reinforcedconcrete stringers. This type of pile-trestle was first designed by Mr. Cartlidgeand has been in use on the Chicago, Burlington and Quincy Rail-road long enough to warrant the view that it is a durable and BRIDGES, TRESTLES AND CULVERTS 65 satisfactory form of construction. It apparently may be used toreplace wooden trestles of low and medium height where thefeatures of short span and adaptation to ground slope are
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
