Nick,
That's interesting about K4's on the NYC! I was looking at steamlocomotive.com and there is a roster of their pacifics listed. They had their own K3's and K5s but no K-4 was listed. I thought "well that makes sense, seeing as how the PRR was their main competetion and their flagship locomotive was called a K4." Were the NYC's K-4s letter for the Central or were they left as PRR? (In a way, it sort of seems like Chevy putting a Mustang engine in their Corvette. Know what I mean? Not disputing your book, just commenting that its interesting. )
Maybe you could scan the picture and post or emai it. I'd be interested to see it.
Mark