Re: Northern Pacific Automobile Box Car NP 8029

Daniel A. Mitchell

That’s very true. We are talking wood construction here. Wood is NOT stable. It expands, contracts, bends, warps, twists, and does all manner of distortions … and every board is different. One could very carefully match every board, planing, sanding, jointing, etc. (FAR more than was ever done in actual car construction), and produce a near-perfect car side. In a few days everything would be out-of-whack again due to changes in humidity and temperature. It’s just not stable. And it would all keep changing every few days for the life of the car.

And no steel frame can totally prevent this. Resist, yes ... prevent, no. Large scale (carside) warps are unlikely since all the boards warp randomly.

Actually, the older the car gets the less it would keep changing, as the stresses and strains within the wood would gradually relax with age. The most dramatic changes would occur in the car's first year of life. The distortions were already starting as the car was rolled out of the builder’s shop.

Dan Mitchell

On Jul 19, 2022, at 9:59 PM, Ted Larson via <mhrreast@...> wrote:

Another consideration is slight warping of the boards which would create slight offset of the horizontal joints.  

Ted Larson   ---   GN in 1965   --- 

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