----- Original Message -----
From: Anthony Thompson
Kurt Laughlin wrote:

What was the composition of the steel in the frames? Did it require
heat treatment?

I would have to dig out the compositions, but I doubt it was heat
treated. It could have been, of course, as very large annealing
furnaces certainly existed.
----- Original Message -----

But it was steel, right? I know there were enormous cast iron parts made back into the 1800's.

----- Original Message -----
If you mean quenched and tempered (!), hell
no! But if you are attempting to separate armor issues from railroad
issues, okay, but few if any large railroad castings, such as the PRR
F30 cars originally discussed, needed heat treatment.
----- Original Message -----

Yes, armor required quenching. The size of quenching pits was apparently a limiting physical factor for the use of cast armor once the metallurgy and foundry practice had been worked out. Neccessity - WW II - overcame that in short order, however.

An earlier post compared the F30a (cast for the PRR by GSC) negatively to the GSC "Commonwealth" car. I'm not sure what the time span was between the two, but I think it was around 10 or 15 years. In the cast armor arena the technology went from very limited, basic applications to virtually entire tanks and advanced materials (such as steel-ceramic composites) in the space of 10-12 years. Clearly in the mid-20th century casting design and technology was making great strides. So, if making an entire freight car from one casting was a new or previously unsuccessful idea at the time of the F30a, the fact that the GSC (PRR F41) built 10 or more years later was more elegantly designed and manufactured is hardly surprising, nor is it indicative of poor design in the F30a.

KL