> Any Superintendent bulletins, general notices or
other notices or bulletins that were in effect when
the timetable took effect would have been incorporated
into the new timetable. As would Mechanical Department
bulletins or instructions.

Not necessarily. This would also depend on the railroad's practices with respect to the information.

> A close look at the rulebook in effect at the time shows
zip, zilch, nada about wheels.

Big deal, besides, it wouldn't be in the Book of Rules.

> Again, how would a crew determine what kind of wheels
a car had without actually looking at each wheel for
stampings?

FWIW, steel wheels, both cast and wrought, have stampings. CI wheels, on the other hand, have cast-in lettering, but no stampings.

Rest assured once "they" figured out the problem, you the operating employee would be informed. The question is when did the figure out the problem, 1930s? 1940s? 1950s? Obviously if it post-dated your ETTs etc., these will not have the information. As I said before, today neither you nor I have in toto access to this sort of information. As another post has mentioned, with only rare exceptions, freight trains of the 1930s-1940s era simply did not go much over 45-50, so the problem didn't wasn't an issue until freight speeds increased after the War. John H. White says they ARR banned CI wheels in interchange in 1958.