RAILROAD CONSTRUCTION 281 



the top log and tupelo for the lower ones. The bents are placed 

 at 6-foot intervals and are composed of two piles driven 56I 

 inches apart, center to center. 



A pile driver crew for building a road of this character is made 

 up of eight men who can cut and drive from twenty to thirty-six 

 piles (from 60 to 100 feet of track) per day of ten hours. The 

 roads are built from 2 to 6 feet above the ground level, and the 

 piles are sawed off at the desired height. 



Stringers 8 by 8 inches, or 8 by 10 inches, are laid on top of 

 the piles and on these 6- by 8-inch by 8-foot crossties are laid, 

 24 inches center to center. 



Thirty-five or 45-pound steel rails are used. 



Rod locomotives of from thirty to forty tons are generally 

 employed. 



The approximate cost, per mile, of a road of this character is 

 $1400 for labor, and $1100 for stringers and crossties. 



A road of similar character constructed on swampy ground in 

 the State of Washington cost $1300 per mile, exclusive of the 

 value of the timber used.^ 



Framed Trestles. — These are made both of round and squared 

 timbers, but if the former must be brought from a considerable 

 distance it is advisable to use the latter because they are easier 

 to fit, and are more durable. 



The frames, or bents, consist of four supports, or legs, made 

 of round timber from 15 to 18 inches in diameter or 10- by 

 1 2-inch, or 1 2- by 1 2-inch squared timbers. On a standard-gauge 

 road two of the legs are vertical and 36 inches apart, while the 

 other two legs are given a batter of from 2 to 3 inches for each 

 foot of height. The legs rest on a timber called a sill to which 

 they are drift-bolted. Sills vary in length according to the height 

 of the trestle and project about 2 feet beyond the base of the 

 outer legs. The tops of the legs are covered with a cap 12 or 

 14 feet long on which the stringers rest. 



Framed bents may rest on mud sills, or piles. Where mud 

 sills are used they are frequently 12 by 12 inches by 4 feet and 

 are placed at right angles to the bent, and a sufhcient number 

 ^ See The Timberman, August, 1910, pp. 37-38. 



