Page 75 - 39. MRH13-05-May2013
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Cast steel trucks with integral journal boxes
The ultimate development of cast steel truck side frames was
to incorporate the journal boxes as an integral part of the side
frame casting. This was first accomplished in the Bettendorf
T-section truck, developed and patented the by Bettendorf
Steel Axle Co. The T-section chords of these side frames were
arranged as equilateral triangles (14 and 15). The Bettendorf
truck was strong, relatively light, and immune to the journal
boxes becoming loose and misaligned, and it quickly became
14
14: The casting of the journal boxes as integral parts of
the Bettendorf T-section side frames is seen clearly here.
This arrangement eliminated problems with journal boxes
working loose and becoming misaligned but required the
truck to be dismantled whenever a wheelset was changed.
Freight Car Trucks - 7
15
15: A later, improved version of the Bettendorf T-section
truck. Note the stiffening ribs above the journal boxes and
between the flange and web of the T-section side frame.
popular with some railroads and private car owners. What dis-
couraged more widespread adoption was the fact that replac-
ing a wheelset required the entire truck to be dismantled,
rather than just jacking up the frame and removing the journal
box bolts, as on Andrews and Vulcan trucks.
On lighter cars, Bettendorf T-section trucks gave good service,
but when loaded more heavily, as on 50 ton boxcars, the side
frames were prone to cracking where stresses were highest at
the lower corners of the spring box. This weakness was cured
by casting the side frames with U-section chords, a change that
Bettendorf adopted around 1920, foreshadowing the universal
adoption of U-section cast steel side frames in the years that
followed. (16). Eventually, in 1956, the AAR banned all trucks
with L- or T-section side frames from interchange.
ARA "Standard" trucks
One of the trucks that adopted the Bettendorf concept of
integrally-cast journal boxes with U-section side frames was
MRH-May 2013
