Paul, you and your photos are what inspired me to find four USAT Southern Pacific GP9’s (two Bloody Nose and two Black Widows) and convert them to Airwire/Battery operation. Left to do is to take the incandescent bulbs out of the engines and convert them to LED’s. Down the road, I’d like to install oscillating Mars lights (Gyralights?) on the engines. I don’t trust myself doing this; I would rather turn the locos over to someone more experienced at it than I. I really like the prototypical lighting and other mods on your Geeps!
A few more photos of your layout later. Glad I archived them!