Re: LRX Image...


Anthony Thompson <thompson@...>
 

Richard Hendrickson wrote:
Exactly. The two truss rods were directly under, or just on either side of, the center sill. There were no other truss rods, and the
side sills, though concealed, were apparently conventional steel angles or channels.
By the time of the 1932 ARA design, it had become evident that "side sills" played little role in structural stiffness or strength of a steel car, and they became vestigial. Center sills likewise became much more modest sections, mainly because of the large contribution of the side sheets. But even in a 1920s car without steel sheathing, deep fishbellies like the USRA underframe were overdesigned, as later analysis and tests showed. The truss rods may or may not have been really needed in cars like the LRX ones we're talking about, but no doubt they gave a sensation of comfort to old-school mechanical designers. <g>

Tony Thompson Editor, Signature Press, Berkeley, CA
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