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and several truck manufacturers introduced trucks whose side
frames and bolsters were made of pressed steel parts riveted
together. Some of these were merely variations on the arch bar
design in which pressed steel replaced steel bars (4). Others
had one-piece pressed steel side frames with the journal boxes
sliding in vertical pedestal jaws and coil springs above the
boxes. The most widely used of these was the Fox truck, made
by the Pressed Steel Car Co. (5).
Trucks with one-piece pressed steel side frames eliminated
the bolts-and-nuts assembly of arch bar side frames but, after
some years in service, they began to develop other prob-
lems that proved to be inherent in the pedestal-jaw design.
Unless the wearing surfaces of the pedestal jaws and journal
boxes received regular lubrication, which seldom happened,
rapid wear resulted. The journal boxes could then become
5
5: A Fox truck made by the Pressed Steel Car Co.
Many Fox trucks had springs only above the journal
boxes, but this one also had leaf springs between the
bolster and side frames. The downfall of these trucks
was the tendency of the journal boxes to stick and jam
in the vertical pedestal jaws.
Freight Car Trucks - 4
index contents
MRH-May 2013