As I posted a while back, I purchased an MTH PRR D16 4-4-0, which models an as-built D16a or D16d, with the intent of turning it into a 20’s-era D16b like this one:
(photo from http://prr8157.deviantart.com/...6b-no-1039-325748232)
Note that this differs from a D16sb in that it hasn’t received piston-valve cylinders, but it has received an electric headlight with generator and slat pilot. Another thing I liked about it is the shorter smokebox. It appears that some D16s had it - more often on Lines West, but the photo above appears to not be Lines West. Perhaps a real PRR expert can chime in?
The photos below show many of the changes and added details, but the biggest job was shortening the smokebox. Thankfully, there was plenty of room inside. The smokebox front is from the MTH A5 0-4-0, and had to be reduced in diameter to fit. All it took was a strong stomach and a Dremel cut-off wheel. The rivets were lost in the process, so I learned how to apply rivet decals!
Before:
After:
My engine crews are really appreciating the convenience of the electric headlight. The smokebox was painted with my own graphite mix (flat black with a little metallic silver) and hit with Dullcote, which I think looks much better than the original paint. I had hoped to replace the 80" drivers with 68" ones, as on the D16b, but (long story short) it just hasn't worked out - yet. So, for now, it's a modernized D16d!