The Pennsylvania Railroad
Had Adopted Superpower?
The PRR is notorious for sticking with "conventional" steam power long after other roads had adopted the "superpower" design concepts first articulated by Lima in 1929. When they finally did start exploring new steam locomotive design concepts, it was in the unconventional direction of very large duplex drive machines. The only exceptions were the 125 class J1 Texas type freight locomotives they acquired during WWII, a design that they copied directly from the Chesapeake and Ohio.
These pictures explore what PRR superpower might have looked like, had the railroad acquired it.
A 4-6-4, or Hudson type, locomotive, although I doubt that the PRR would have called it that. If they followed their usual classification practices, this would probably have been class P6.
The same engine, only streamlined along the lines of the P5a electrics.
A 2-8-4, or Berkshire, type. Since this is a wheel arrangement that was new to the PRR it would have needed a new class letter. Perhaps U1?
A 4-8-4. This would probably have been class R2.