"Were roof walk boards rough sawn? They would be cheaper and the
rough surface would provide greater traction. Could those roof
walks boards be second grade lumber with knots?"
Rough sawn? You must mean FULL SAWN
vs. ROUGH SAWN because the answer is yes if the supplier specification was
"nominal to 23/32" rough or surfaced. Full sawn would have been 1-inch plus or
minus and no regard as to all boards being exactly the same, just roughly...
My guess would be that there was a spec for "rough sawn to nominal" if
the end user would allow it. The other option could have been S1S2E or
surfaced one side and two edges which would have allowed for a rough face. But
all this is unlikely as most spec's would have read S4S ~ surfaced four sides
to keep the boards when applied uniform. The quality would have been
very specific with reference to grade as well. Likely mostly some form of
"clears" or "uppers" i.e. "D&btr ~ no hole" a very common industrial
grade. Look at the photo that Tim O'Connor posted of the inside view of the
Southern stock car and look at the sides. To me that represents Kiln Dried
Southern Yellow pine D&btr no hole S4S EE.
"How about boards used for siding on open top cars? No need for a
tight seal on these. I recall a photo of
a CNJ wood side gondola with light peeking out between
2 side boards."
That is a photo I would like to see,
because that was not what was intended in my thoughts. Mother Nature will
takes her toll though.
"Looking at an erection drawing of a single sheathed box car, I was
surprised to find the horizontal side boards were tongue and groove. Was
Yes absolutely, in order to keep the
house car "tight" you would need that or at least ship lapped. Tongues up and
Grooves down if the sheathing was horizontal. Tongue and Groove
(T&G) for horizontal siding as well of the best quality.
"Some builders photos of single sheathed box cars show the
horizontal boards so tight that you can barely tell one board from the next.
No room for expansion on