Will,
I can't read 100% this on my images. But the first letter is a K and the rest looks like some numbers.
So I think its the lettering "K28".
More images on my web site at [
www.whitepassfan.net]
As far as we know, the engines were always under control of the USATC, so there should be no mark or lettering of the WP&YR.
But don't forget the add the winter wood cover of the tender.
I'm rebuilding my Sunset On3 scale into a USA engine, too
Boerries
[
www.whitepassfan.net]