Re: History of corrugated box car ends?


Jeff English
 

Experimental pressed sheet steel corrugated ends were around before
1910. NYC's first experimental use was 1912 and their first
production application of them was 1914.

This might not be clear to non-engineers, but the idea is not
necessarily to increase "strength" as to increase resiliency, or
IOW, the ability of the end to absorb the energy of impact of the
load shifting against its inside. By absorbing energy, the impact
event is spread out over time (e.g., from 0.1 sec to 0.25 sec),
resulting in a lower peak stress on the rivets that attach the ends
to the sides, roof and end sill, increasing the threshold at which
the end would tear away from its attachment. Also reducing the peak
bending stress within the end sheet itself, thereby increasing the
threshold at which the end would become permanently distorted. It's
all about controlling a high-energy event to minimize peak
stresses. Introducing the corrugations did increase "strength" by
making the material stiffer in the horizontal direction, but it also
gave the end the ability to stetch elastically in the vertical
direction. That elastic stretching gives the ability to absorb the
energy of the impact.

I suppose the amount of damage to the lading would be slightly
reduced as well, but that was not the primary objective.

Hope this helps -

Jeff English
Troy, New York


--- In STMFC@..., "Dean Payne" <deanpayne@n...> wrote:

A friend pointed to a photo and said "It can't be too early, it
has
corrugated ends", after which I told him corrugated ends were much
earlier than he thought. The USRA box cars had corrugated ends in
the late teens and... I guess I don't have a clear impression
beyond
that! When were the more common types introduced? I know that
only
the very last X29's had corrugated ends, but I don't think that
the
USRA cars introduced them, nor that the X29's were the last hurrah
for plate ends. I gotta admit, I find myself a bit puzzled about
the
advantage of corrugated over plate; I guess it's to add strength
when
a load shifts and clobbers the end due to braking or slack
action. I
think they tried corrugated sides on some gons, right? The sides
still got all beat up... and I don't remember seeing a photo of a
plate end car with dents indicating a need for the strength of a
corrugated end... I don't remember any corrugated end photos with
end damage, either.
Dean Payne

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