The Life-Like Heritage series Steam(Now owned by Walthers) built some USRA 2-8-8-2's which were nearly identical to the Norfolk & Western Y-3 class. During World War 2, the N&W was one of the few RR's that had surplus locomotives, and the Union Pacific bought 5, the Santa Fe bought 8 and the Pennsy got 6 of the Beasts. LL, did them in all three of these road names, I have 2 of them, and along with my Lionel Challengers and Trix (by Marklin) Big Boys(2 of those also) they are the smoothest running locomotives that I have ever run, silky smooth. They are supposed to handle 18" curves and #4 turnouts.
The Bachmann Spectrum 2-6-6-2 should also fit your needs, but you would need to apply a bit of "Modeler's License" to these, as I don't beleive that any of your chosen prototypes ever had these, but in the WWII era, Locomotives ended up in all kinds of strange places, far from Home, like the N&W Y-3's on the UP and Santa Fe. Some Duluth, Misabee & Iron Range 2-8-8-4's would also migrate to the Denver & Rio Grande Western during the winter months, when the Great Lakes were frozen over(the DM&IR hauled Iron ore to the ore docks on the lakes).
I was tempted by the Bachmann 2-6-6-2 myself, I model the UP, which as far as I can tell, never had any 2-6-6-2's, but I was tempted to letter one for the UP any way, strange things did happen in that era, and most people, other than a serious UP Fan, likely wouldn't know that they never had those any way. The Spectrum is a Good looking, and from what I hear, a Good running model. Then I got bit by the sound virus, and there were enough other options, that I never did buy a Spectrum 2-6-6-2.