190 BULLETIN 111, U. S. DEPAETMENT OF AGRICULTUEE. 



a number of years at the rate of $1,500 per mile. Still another oper- 

 ator who constructs from 14 to 30 miles of spur track per year has 

 found that the cost of clearing right of way and grading is from $27 

 to $oO per station. This work includes cuts to a depth of 10 feet, 

 fills to a height of 7 feet, with many of the cuts and fills running 

 more than 5 feet. The operator lets the contract to two men, and 

 the net profit to each has never been less than $250 per mile. 



TIMBEEWOKK. 



Much printed matter dealing with the character and cost of crib- 

 bing, trestles, revetments, etc., and methods of construction is avail- 

 able. A simple treatment is given in " Logging," by R. C Bryant. 

 For this reason the discussion given here is only very general. 



(1) Crib work. — In the past cribwork was extensively used and 

 is still used in places to cross slight depressions or swampy ground. 

 It consists of large logs laid at right angles to the track about 12 

 feet apart, center to center. Two logs are laid lengthwise on these 

 logs for stringers. The cost of cribbing, when the height runs from 

 4 to 5 feet, is from $0.50 to $0.75 per linear foot, exclusive of the 

 stumpage. From 400,000 to 500,000 feet board measure of logs is 

 required per mile. 



Cribwork, however, frequently costs more than this, as is shown 

 ill the following cases: 



Case 1. — The cost of a three-stringer crib bridge 83 feet in length 

 and 5 feet high was $223.75, or $2.70 per linear foot, segregated as 

 follows : 



Excavating, labor $12.50 



Construction, labor 116. 25 



Rent of equipment 90.00 



Finishing, labor 5. 00 



Total 223. 75 



Case 2. — The cost of a cribbing 100 feet in length and averaging 10 

 feet in height was $542.38, or $5.43 per linear foot, segregated as 

 follows : 



Excavating, labor $66. 75 



Construction, labor 290. 63 



Rent of equipment 172.00 



Finishing, labor 13. 00 



Total 542. 3S 



This structure forms the tail of a switchback, with two bridges 

 resting on one foundation, the aligmiient necessitating three 

 stringers. There is one span 50 feet in length and two spans 25 feet 

 in length. 



