26 
BULLETIN 17, U. S. DEPARTMENT OF AGRICULTURE. 
in this shipment, the whole car being warmer than is a good refrig- 
erator, even at the bunker. It seems impossible during warm weather 
to reduce the air at the center of thinly insulated cars to the tem- 
perature best suited to the transportation of dressed poultry. 
EFFECT OF CAPACITY. 
The cars of type D, which are the most efficient of those studied, 
are likewise the smallest in point of cubic capacity. The total 
available space in these cars is about 1,640 cubic feet. Type C 
provides about 1,833 cubic feet of space, but with this increased 
, loading capacity 
y : 
there is a decrease in 
the power to main- 
tain low tempera- 
tures. Type C, how- 
ever, has one-half 
inch less insulation 
on the roof than type D. The cars of 
type B, which reduce the roof insulation 
by still another one-half inch, offer about 
2,050 cubic feet of space, but at a big 
sacrifice in efficiency. Type A, with the 
same insulation as type B, is smaller, 
1,909 cubic feet, and is correspondingly 
higher in efficiency. 
Another type of car, with insulation 
as represented in figure 5, / (sides), fig- 
ure 6, d (roof), and figure 7, e (floor), has 
an available space of 2,010 cubic feet. 
Even with the 
three layers of 
one-half inch 
"^^ insulation 
Fig. 11.— Iron tank bunker, used in type D car. thr O U °"hout 
there is a wide difference in temperature between the center and 
ends of the car during warm weather (fig. 14). From this figure it 
is evident that, in the very large cars, one and one-half inches of 
insulation is not enough to insure the best temperatures for poultry 
transportation while comparatively high atmospheric temperatures 
prevail. Figure 15 gives temperature records in cars insulated, 
as shown in figure 5, e (sides), figure 6, e (roof), and figure 7,f (floor). 
These cars are of the large type, but with the 2 inches of insulation 
on the roof the interior temperatures at the bunker were fairly 
satisfactory. 
The results, as a whole, indicate that large cars require additional 
insulation to yield the same efficiency as the small cars. 
