RAILROAD CONSTRUCTION 



283 



Payment for pile trestles, when built by contract, is made on 

 the basis of the number of piles driven and the amount of sawed 

 timber used in the remainder of the structure. 



Dunnage or Dust Road. — This is a type of cheap logging 

 road employed for spurs in the cypress swamps of Louisiana 

 where the bottom is too soft for dirt ballast, and the cost of 

 a pile road is not warranted by the amount of timber to be 

 removed. 



Fig. 79. — The Foundation for a Dunnage Road. Louisiana. 



The construction of a dunnage road is preceded by clearing 

 a right-of-way from 15 to 20 feet wide from which all brush is 

 cut and stumps removed from the line of the roadbed. The latter 

 is covered with small poles from 5 to 6 inches in diameter, laid 

 close together, lengthwise of the right-of-way. These give a 

 wide bearing surface and serve as a bed on which the ballast is 

 placed. The crossties are laid on the poles and the rails spiked 



