Re: from 40' 6' to 50' 6" box cars
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water.kresse@...
"Forklift-proofing" made strength and thickness an issue on box cars. Part of Lt Wt is the addition of DF-type rails. Older 40-ft box cars had bulkheads and floor coverings put in their ends and on their wooden flors to ship heavy iron castings for the auto industry.
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ALL GOOD FEEDBACK! Thanks guys. NOW I have to get the C&O Rwy Cost Sheets out and determine typical 40-ft to 50-ft box purchasing cost differentials. Al Kresse
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From: Anthony Thompson <thompson@...> AL Kresse wrote: I agree on the Lt Wt issue. They experimented with 0.075" thk HSLAThis is a subtle point. The stronger steel is no STIFFER, so making it thinner makes it prone to buckling, and that's what happened to some box cars with thinner side sheets: wrinkling, etc. This can be solved by adding intermediate posts between the regular side posts (that's the so-called "Alternate Center Riveting" or ACR box car design), but then the weight of the extra posts offsets the weight saving of the thinner steel. This emphasizes that much of structural design, including box cars, is based on stiffness and not on strength. The best illustration of that is the dreadnaught end. It is trivially STRONGER than a flat end, but greatly STIFFER. The same goes for underframes, sides and roofs. Anthony Thompson Dept. of Materials Science & Engineering University of California, Berkeley thompsonmarytony@...
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