Page 89 - 39. MRH13-05-May2013
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57: Commonwealth, primarily a maker of passenger
car trucks, offered this high-speed truck whose
drop equalizers and combination of coil and elliptic
springs gave it the appearance of a short wheelbase
passenger car truck.
High-speed trucks
In the 1930s, as a number of railroads began using box and
refrigerator cars in passenger express service, freight car trucks
began to be developed for operation at passenger train speeds.
The ASF Simplex truck, with its long and flexible leaf springs,
was an example of a truck developed for this purpose (54).
Other efforts to produce a high-speed freight car truck resulted
in the Barber S-5 and Gould trucks with sprung journal boxes
in side frame pedestal jaws (55 and 56). Commonwealth also
offered a short wheelbase passenger-car-type truck with drop
equalizers which had both coil and leaf springs (57).
The Allied Full Cushion truck, introduced in 1940, provided a
better ride at higher speeds and was applied by a number of
railroads to freight cars in passenger train service, as well as to
a large number of freight-car-based troop sleepers and kitchen
cars built during World War II for the federal government
(58). However, it turned out that Allied trucks had derailment
Freight Car Trucks - 21
58
58: When it first appeared ca. 1941, the Allied Full
Cushion truck was a revolutionary effort to provide
a better riding high-speed truck for freight cars in
passenger express service. However, its tendency to
derail proved impossible to correct completely, and it
was outlawed in interchange in 1955.
problems, and intensive efforts to cure this shortcoming were
only partly successful, so they were little-used after the war,
and finally were banned in interchange in 1955.
After World War II, the Chrysler Corporation attempted to
improve truck performance by the use of automotive tech-
nology in the Chrysler FR-5 truck (59). This truck had a swing
motion bolster and hydraulic shock absorbers, among other
features, but these innovations did not compensate for its
additional cost and increased maintenance requirements, and
it was not widely adopted.
Heavy-duty trucks
Relatively few freight cars built between 1900 and 1960 had
nominal capacities exceeded 70 tons. However, early in the
20th century some very large coal hoppers and gondolas were
constructed with capacities of up to 100 tons, and those cars
required special high-capacity six wheel trucks. Usually these
57
MRH-May 2013
