. Elements of railroad track and construction . es, and are fastenedto the ties by 7 by |-inch lag-screws. The inner edgeof the timber is 1 foot from the gauge of the rail, asshown in Fig. 176; this distance gives the guard raila full chance to act in case of a derailment, withoutinterference by the guard timber. 336. Ballast Roadbed for Trestles.*—In Fig. 180is shown the cross-section of a ballast floor system for a pile cap A 16ft. long,and is drift-bolted to sixpiles forming the trestle bent, the bents being 14 feet apart. Nineteen8 by 14-inch stringers B B, fou
. Elements of railroad track and construction . es, and are fastenedto the ties by 7 by |-inch lag-screws. The inner edgeof the timber is 1 foot from the gauge of the rail, asshown in Fig. 176; this distance gives the guard raila full chance to act in case of a derailment, withoutinterference by the guard timber. 336. Ballast Roadbed for Trestles.*—In Fig. 180is shown the cross-section of a ballast floor system for a pile cap A 16ft. long,and is drift-bolted to sixpiles forming the trestle bent, the bents being 14 feet apart. Nineteen8 by 14-inch stringers B B, four of which are 28 feet, andfifteen of which are 14 feet long, rest directly upon thecaps and form the floor of the roadbed. The four 28-footstringers are placed one on each outer edge and one undereach rail. The stringers are held in position by 2 by 6-inch planks C C, which are spiked to the bottoms ofthe stringers by 6 by f-inch boat spikes, D D. Two stripsC C are used at each bent, one being spiked on each side* Illinois Central Railroad,. Fig. 180. TRESTLES. 329 of the cap. The ballast is retained by 8 by 10-inchtimbers E E, 28 feet long, which are fastened over the out-side stringers as shown in the figure, f-inch bolts F F,41 inches Jong, running through this timber, the stringer,and the cap. The timbers E E are also held in place andkept from overturning by cast-iron angles G G, which arebolted to the timber and the stringers. Cross-tiesH H, 6 by 8 inches and 8 feet long, are laid with one footof ballast under them. The ballast extends horizontallyone foot from each end of the tie and then has a slopeof 1 on 1^. All the timbers in the above structure are first framedand then creosoted and erected. There is a space of oneinch between the stringers, which allows the water todrain out, thus reducing the tendency of the timbersto decay. This form of trestle superstructure has two importantadvantages over the ordinary superstructure, viz., it isfar less liable to be damaged
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcetc, bookyear191
