Re: Caboose trucks GN


soolinehistory <destorzek@...>
 

--- In STMFC@..., "brianleppert@..." <brianleppert@...> wrote:

The transoms on GN's cabooses are kind of crude looking, IMO, and GN was using freight car truck side frames instead of special ones as on the Bettendorf trucks. Perhaps Great Northern fabricated these trucks themselves? AFAIK, these are unique to GN.

Brian Leppert
Tahoe Model Works
Carson City, NV
Tyrone and I had discussed these in person a while back, and I postulated that these were an early version of the Bettendorf cast transom, meant to fit a standard sideframe, but I could never find anything to substantiate this.

A question that comes to my mind is what holds these trucks together? For that matter, what holds a Barber-Bettendorf truck together?

The earlier iterations of this design, using wood transoms and arch bar sideframes, just had the transoms bolted directly to the side frame. This essentially locked all four wheels into a non equalized rigid frame, much like a one piece molded model truck. However, I'm sure the wood transoms were limber enough that they just twisted sufficiently to allow all four wheels to remain in contact with uneven track. Even the later swing motion archbar trucks that used steel channel section transoms were likely somewhat flexible, since the transoms were not unified into a box shaped fabrication with cover plates. The Bettendorf cast transoms are a box section, and are not likely to twist to allow the sideframes to equalize. That means that there must be some allowance for motion between the sideframe and the end of the transom casting, and indeed, they do obviously appear to be separate pieces with some clearance between. But, what held them together? It isn't very obvious from the drawings, and I've never had the opportunity to dismantle a prototype truck of this sort.

Dennis

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