26 BULLETIN 463, TT. S. DEPARTMENT OF AGRICULTURE. 
The rate at which earth can be excavated with an elevating grader 
is relatively very high when conditions are favorable and the grader 
can be kept moving. But there are a number of rather complicated 
parts about such a machine which sometimes get out of order, 
and the work also is hampered frequently by many unforeseen con- 
tingencies, such as "bogging'' of the wheels, choking of the plow 
or the elevator belt, occurrence of buried stumps or stones in the 
excavation, etc. For these reasons the actual capacity of elevating 
graders, considered over a long period, seldom is more than about 
one-third or one-half the rated capacity, and where the material is 
loaded into wagons as it is excavated the actual capacity of the ma- 
chine may be reduced still further. Elevating graders of the size 
used ordinarily in road work have a rated capacity of about 100 
cubic yards per hour. 
ITSE OF SCRAPERS, WAGONS, ETC. 
To grade a road of any considerable length, no matter where it is 
located, usually will require a considerable amount of work with 
devices other than the grading machine and elevating grader. 
The latter machines, as previously explained, may be very economi- 
cal for special conditions to which they are adapted. But these 
special conditions seldom prevail fcr more than comparatively short 
stretches of road without sections intervening which require that a 
relatively large volume of material be moved from excavation to em- 
bankment within a distance of only a few hundred feet. Figure 15 
shows a typical cross section for an earth road, where the grading 
TYPICAL CROSS SECTION FOR EARTH ROAD 
*W.* width of road between ditches, not less than 20 feet 
*D" vanes from 2 feet to fc feet depending on the rainfall and grade. 
"H". crown, varies from ^ inch to the foot for level grade to I inch to 
the foot for a grade of 5% 
Fig. 15. 
machine hardly could be used advantageously except for finishing 
the road surface. To accomplish work of this kind economically, 
the devices for loosening, loading, and hauling the material must 
all be adapted to turning around quickly in a small space and. not 
infrequently, must be such as to be handled readily over very rough 
ground. Such implements as wagons, wheeled scrapers, drag 
scrapers, and plows therefore should form a part of the equipment 
on practically all road-grading projects. 
The choice of proper implements to employ in moving material 
from excavation to embankment depends, first, on the nature and 
quantity of the material to be moved, and. second, on the length of 
