Figure 6-2.-Forklift truck.
material-handling equipment, use a forklift truck at each
end of the haul for loading, unloading, and stacking.
This will make the operation faster and easier. Figure
6-2 shows a 6,000-pound forklift truck.
TRACTOR-TRAILER TRAINS
The tractor-trailer train (fig. 6-3) is a system that
consists of a self-propelled power unit connected to a
series of trailers. There are various types of tractors used
for pulling the trailers. Tractor-trailer trains can haul
heavier tonnage than carrier-type trucks of equal
horsepower capacity. They can pull trains up to the total
drawbar pull of the tractor. The number of trailers one
tractor can continuously pull depends upon the length
of haul, nature of material, and weight of the load of each
trailer. Under normal conditions, one tractor should be
able to operate with three sets of trailers. One set of
trailers for loading, pulling a second set underway, and
a third set unloading. Tractor-trailer trains are effective
for hauling loads between 400 feet to 1 mile.
WAREHOUSE TRACTORS
A warehouse tractor is an electric- or gasoline-
powered vehicle designed to pull a train of warehouse
trailers. The gasoline-powered models used in the Navy
have pneumatic tires and a rated drawbar pull of 4,000
to 7,500 pounds. Electric-powered models commonly
used in the Navy have solid rubber tires and a rated
drawbar pull of 2,000 or 4,000 pounds. The drawbar
pull, the motive force that a tractor can exert in pushing
or pulling loads, is merely a means of saying tractor
capability. The actual capacity of the tractor is normally
far more than the drawbar-pull rating. For example, a
Figure 6-3.-Tractor-trailer train.
Figure 6-4.-Warehouse tractor.
tractor with a drawbar pull of 4,000 pounds may have
an actual towing capacity of 90 tons.
Five different models of tractors was adopted as
standard for the military services. The 2,000-pound,
drawbar-pull, electric-powered warehouse tractor has
solid rubber tires. It is a light-duty tractor for operation
in warehouses and other closed storage areas.
The 4,000-pound, drawbar-pull, electric-powered
warehouse tractor (fig. 6-4) has solid rubber tires. It is
the standard heavy-duty tractor for indoor warehousing
operations. This type of tractor is used in a similar
manner and for the same purposes as the light-duty,
2,000-pound model.
6-11
