HIGHWAY CONSTRUCTION 59 



20 inches, but it varies from that up to the standard railroad gauge 

 of 56 J inches. 



Dump Wagons. (Fig. 40.) The use of these wagons for mov- 

 ing excavated earth, etc., and for transporting materials such as sand, 

 gravel, etc., materially shortens the time required for unloading the 

 ordinary form of contractor's wagon; having no reach or jx>le con- 

 necting the rear axle with the center bearing of the front axle, they 

 may be cramped short and the load deposited just where required. 

 They are operated by the driver, and the capacity ranges from .V> 

 to 45 cubic feet. 



Mechanical Graders are used extensively in the making and 

 maintaining of earth roads. They excavate and move earth more 

 expeditiously and economically than can be done by hand; they are 

 called by various names, such as "road machines," "graders," 

 "road hones," etc. Their general form is shown in Fig. 41. 



Briefly described, they consist of a large blade made entirely 

 of steel or of iron, or wood shod with steel, which is so arranged by 

 mechanism attached to the frame from which it is suspended that it 

 can be adjusted and fixed in any direction by the operator. In their 

 action they combine the work of excavating and transporting the 



Fig. 41. Mechanical Grader. 



earth. They have been chiefly employed in the forming and main- 

 tenance of earth roads, but may be also advantageously used in pre- 

 paring the subgrade surface of roads for the reception of broken 

 stone or other improved covering. 



A large variety of such machines are on the market. The 

 "New Era" grader excavates the material from side ditches, and 



