Roof Terminology (was reefer roofs)

Jeff English

Clark Propst <> wrote:

yes, they had diagonal panel roofs
and, no, they did not have a groove along the top of the sides.
Just to reinforce the record which does exist in the archive for
this list, the term for the type of roof construction under discussion
has generally been "overhanging eave", although I do not know if
this is documented in the trade literature.
Moreover, here is some more specific information on how roofs
in the all-steel-roof era were constructed. At some point it was
realized that using a rolled Z-section steel eave is an effective way
to transition from roof panels to side panels and direct the flow of
water outside the car structure.
This is the type of construction seen on the majority of classic-
era steel box cars, especially the AAR-standard designs of the 30s
& 40s. Sometimes you will see this referred to as "Z-bar eaves",
which I believe is an effective, descriptive term, although I again do
not know about its contemporary documentation.
For the overhanging eave, a special shape is rolled for which I
am not aware of any application other than freight car eaves, which
is officially called a "ZU-section". Picture the Z-bar with an
additional leg for the roof panels to attach to without being folded

I think it is better to refer to "overhanging eaves" or "ZU eaves" than
to say a car has a "groove along the top of the sides".
All those reefers and thousands of box cars built in the 40s &
50s used the ZU-section eave member. I am still trying to
determine if the 30,000-odd NYC cars built in the 20s used the ZU-
section or an assembly of a Z and an angle. Such an assembly
would have been easily made using standard rolled sections which
were available then and still are today. My visual inspection of a
surviving car in Green Island, NY, makes me believe it has one-
piece ZU-section eaves, although this would seem to argue that
NYC was able to convince a rolling mill to add this to their line for
the sake of about 2.4 million feet of the stuff. I don't know if this
amount of production over ten years would have been sufficient to
get a mill to create a new section.

Jeff English Troy, New York
Proto:64 Classic Era Railroad Modeling

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