Thanks for all the responses. I have come to the point when I must decide which particular version (builder, railroad, etc) of the standard USRA car I'm trying to build and have decided to try and model what the original USRA designers called for, which means following the original drawing as closely as possible, warts and all.
Floor boards and sheathing connection:
As Dennis suggested , the original GA side view of the car show the top of the floor boards as a dotted line, suggesting they were inside the side sheathing, but with bulge plates (thanks for giving me their name) placed between the the vertical supports. This does not seem like a bad design for keeping the end grain of the floor boards protected and the sides tight against the floor boards. But when I looked at the pictures, in most cases this does not seem to be what was done. Examples:
From the July 1980 Mainline Modeler article-
--PRR #564287, page 43
--C&NW #144694, page 48. This photo is described as from Jan 1919 as the car came form the American Car and Foundry plant.
--B&O #XM 2157, page 49
Other photos-
--D&H #17432 (http://steamerafreightcars.com/modeling/vm/vm10dhpics.html)
--CC&O #8257 wreck picture (http://www.steamerafreightcars.com/gallery/wreck/crr8257main.html).
--CC&O #8024 is shown as delivered in the April 1919 Railway and Locomotive Engineering article on USRA cars delivered to CC&O and built by Bettendorf Company
--D&H #17225 (http://mattforsyth.com/?attachment_id=425)
--C&NW #144694, April 1919 Railway and Locomotive Engineering
Jack as you suggested, in looking at these, I don't think they show that the sheathing sits directly on the floor boards, if that were the case the line would not look as continuous as it does, but rather as you suggested, there is some sort of "L" bracket tying the side sill, floor boards and sheathing together. This does not seem as would give as much protection from the elements as the original design. (Jack, if doesn't violate any rules, could you send me a scan of the picture you mentioned, RPC17 is out of print and I'm trying to track down a reasonable priced one). All very interesting.
The comments about the floor board clips were very useful. I found a bunch of recent material on them, but noting from the 1920s. This may be pushing things, but in 1919 might they use round head carriage bolts or counter sunk screws for attachment.
Dennis, I do appreciate the lead to Illinois Railway Museum and I am following up on it, but I'm also trying to move ahead with the construction of my model. Apparently Haskell & Barker build 6,000 single sheathed USRA box cars, does anyone know for what lines? Also I have a list of drawing numbers for the USRA standard cars published in the 1919 Railway Review. Would these numbers carry over and be used by the builders? Buying single drawing can get very pricey, so I want to make sure I get the right ones. (As an aside, The NYCHS has a great deal where you can buy a cd with multiple drawings on single topic for a very reasonable price. I bought their cd on class H-6 Mikado and it was wonderful.)
