Re: Need B&O wagontop info from Florida museum


Bob Witt wrote:

Note the M-53 and the M-53A had different Duryea underframes and
actually may account for the different class designations. Â

Scott Seders@...asked:

Bob, what is the difference between the two underframes?
The differences are how the floor stringers are mounted. On the M-53
they are not continuous between the body bolsters, but butt against them
and are fastened with brackets riveted to the cross-bearers. Between the
middle two cross-bearers they are farther from the center line of the
car. The plan in the MM November 1982 issue correctly illustrates the
structure. On the M-53A the floor stringers are continuous between the
body bolsters and the cross-bearers, which are pressed steel, are shaped
(notched) so the stringers can pass over them, which is similar to the
AAR standard underframe construction. There are no doubt other
differences in the cushioning springs, cover plates, etc., but these are
internal in the center sills and are not visible. (A picture here is
worth a thousand words). The underframes for the M-53 were built by
Bethlehem Steel and delivered to the B&O, which then assembled the
wagon-top car bodies on them.

Over the years the design changed so rather than using channels or beams
for the center sills, as on the M-26d and M-26e, the later designs could
accommodate the AAR standard Zee center sills as applied to the M-55c
and M-55h.

The photos on the web site are of a M-53. If you get oriented and look
at the photos with the drawing you can see in some of them how the
stringers mount to the cross-bearers with brackets and do not pass over
this steel component. It seems the earlier design would not be as rigid,
but they lasted over 30 years and did not experience massive failures.

I hope this helps.


Bob Witt
Indianapolis, Indiana

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