I'll stand by the offhanded remark about PRR locomotives. Their prolific use of the squared Belpaire firebox design (I know for the coal they used),
Again, your lack of technical knowledge is amazing! The Belpaire firebox design had NOTHING to do with the fuel burned. Remember that the Great Norther RR also used the Belpaire design, with many of their locomotives using oil fuel. An advantage of the Belpaire design is, all the staybolts are of uniform/standard length in any given area, when compared to a radial stayed firebox design.
flat smokebox fronts, flat pilots, and high mount headlights is not aesthetically pleasing to my eye. Just weird designs.
Well,,,,,,,to each his own, I guess. Then again, I never really cared for the appearance of the Santa Fe steam locomotives, plus I have never been a fan of Baldwin Locomotive Works products. From an experience standpoint, my first choice is, and always will be, Lima Locomotive Works (NKP 700s and SP GS class), followed closely by American Locomotive Works (UP 800s and 3900s).
But back on Hudsons . ATSFs 3460 class was bumped from The Chief by diesels after WWII. NYCs Hudsons were bumped from the 20th Century by 4-8-4s, because they couldn't hack it on the flat "Water Level Route" any more. ATSF only had to use 4-8-4s in the mountains, not on the flat terrain between Chicago and La Junta, CO. Superior 4-6-4 eh ?
You failed to comment on the slippery issues with the Santa Fe 3460 class locomotives.
Now, lets not forget that the NYC J3a Hudsons operated from Harmon, NY to Chicago, IL, taking water on the fly, and only taking fuel (coal) at Cleveland, Ohio.