Re: PRR Crown Trucks


bob_karig <karig@...>
 

I can find no evidence that trucks with separable journal boxes were banned in interchange anytime during the steam era.

In fact, if you go to rule 17 in the 1957 code, you will find that, "The substitution of integral for nonintegral types (of sideframes) is permitted." This certainly implies that nonintegral types of side frames were permitted in interchange. This rule reads the same in 1962.

I suspect the 1957 reference stems from the banning of "I", "T", and "L" section side frames. Specifically, 3 (t) (3-b). "Effective January 1, 1956, cast-steel side frames having "I", "T" or "L" section compression or tension members, prohibited under all cars. From owners. Effective January 1, 1957, this requirement will apply to all cars in interchange."

Since a large number of side-frames with separable journal boxes were produced prior to the introduction of "U" section side frames, this would have cleared them off the road. Note also, that these earlier side frames were narrower and therefore not as strong.

This rule would have also cleared out the old "T" section Bettendorf side frames, so it wasn't just limited to nonintegral side frames.

However, a large number of sideframes with separable journal boxes would have survived. Examples include the USRA side frame, the first ARA "standard" truck with separable journal boxes, and "U" section Vulcan side frames.

Bob Karig

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