B&O underframes


Dear group
In 1917 the B&O ordered a batch of steel underframe freight reefers. Plans were published in the "Railway Age"
trade magazine. The article stated that the underframe was supplied by Ralston. My question is this-is this the SAME underframe as the M-15 DS  box cars i.e. did B&O have a standard underframe design?I can see that the two cars have similar underframes: what I want to know is whether they were exactly the same-say like the Pennsy
X23 and X25 and R7  all have the same underframe.(Things like this come up when you're a rivet counter...)
Thanks for any help you can give
Larry King

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