Re: 4-4-0's

BillD Wrote:
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> Mostly, yes, but this does not explain engine
> classes Q-1, Q-2, S-1 and T-1.

PRR’s motive power glory days were in the teens when they designed the E6s, K4s, L1s, I1s, and M1s. At the time of their introduction (and for a very short time afterwards), these designs, though conservative, were head and shoulders above the rest.

PRR then proceeded to rest on its laurels while the rest of the industry marched ahead until their fleet was hopelessly obsolete, and worn out, just in time for WWII. They then tried to vault ahead again with the Q-1, Q-2, S-1 and T-1, but fumbled badly with overly complicated and unreliable designs that proved their worth by being scrapped within a few years of their construction.

PRR’s designers in the late ‘thirty’s just didn’t have their act together the way that their predecessors in the early teens did. Why they didn’t just build 4-8-4's like everybody else is a mystery. I think it was due to arrogance, “We’re the mighty PRR, and we don’t follow, we lead”.