2 BULLETIN 1398, U. S. DEPARTMENT OF AGRICULTURE 
United States Department of Agriculture in cooperation with officials 
of the railroads and refrigerator-car lines and of car builders who 
were attempting to find the best methods of handling, storing, and 
shipping fruits and vegetables, the United States Railroad Adminis- 
tration issued recommendations for what is now known as the United 
States standard refrigerator car. 
Most of the refrigerator cars built or rebuilt since this type of car 
was recommended do not comply with the United States standard 
specifications in all details, but the essential features—adequate in- 
sulation, basket bunkers of sufficient ice capacity to cool the load 
properly, insulated bulkheads with openings at top and bottom 
large enough to allow free air movement in and out of the ice com- 
partment, and floor racks of sufficient height from the car floor to 
allow an easy unrestricted flow of air under the load—are generally 
recognized by car designers and embodied in their plans. 
INSTALLATION OF WIRE-BASKET BUNKERS 
‘The cars of the United States standard design are equipped with 
wire-basket bunkers (fig. 1) fastened to nailing strips and placed 
about 2 inches from the side and end walls, the ice being supported 
by either a metal or heavy wooden grate placed a short distance from 
the bottom of the compartment. Most cars so equipped are pro- 
vided with a solid insulated bulkhead having an opening of about 
12 inches at the bottom and 14 inches at the top. The space between 
’ the ice receptacle and the car walls permits the free movement of 
air over almost all of the outer surface of the ice in the bunker. 
The wire-basket type of bunker has proved its efficiency, but in 
the repeated attempts of car designers to improve the construction 
and efficiency of refrigerator cars another form of bunker, known as 
the divided wire-basket bunker (fig. 2), has been devised. It em- 
braces the features of the United States standard type but in addi- 
tion has a series of divisions, or flues, for the purpose of decreasing 
the ice capacity and increasing the meltage surface as the ice melts. 
The bunker is divided into four distinct sections by a main par- 
tition placed parallel to the longitudinal axis of the car, consisting 
of two sections of heavy wire netting 4 inches apart extending from 
top to bottom of the bunker and two smaller partitions placed 
parallel to the main partition but extending only about two-thirds 
the height of the bunker. 
These secondary or intermediate partitions are of a construction 
similar to that of the main partition (fig. 3). They act as flues 
and allow air circulation around more of the ice than is the case with 
the United States standard type of recommended bunker construc- 
tion. 
RESULTS OF TEST TRIPS 
As a means of determining the comparative performance of the 
two types of bunkers, two test trips were made, using two cars of 
identical construction for each test except that one was equipped 
with the wire-basket and the other with the divided wire-basket 
bunker. The first test was made in September, 1923, from the State 
-of Washington to Chicago, Il., and the second, from Florida to 
New York City, in June, 1924. Both tests were made possible only 
