The L&N Railroad, later Seaboard System and finally CSX, ran right past the University of Louisville where I did my undergraduate degree. In the later 1980's, I used to see lots of Family Lines power whos paint had seen better days. Most of those locomotives hadn't been re-painted yet into the CSX current version of stealth gray, they were simply re-numbered and many times had a small CSXT located either above or below the new numbers on the cab side.
I happened to come across this Athearn Genesis GP40-2 decorated for the L&N in Family Lines livery. While the L&N only had 10 of these, I though it would be a fun project to model it around 1989. I started by wet sanding the L&N, road number and striping on the cab sides with 1000 grit paper. Then I sprayed a mixture of light gray, refer gray and black to paint the patches. I wasn't concerned with making it perfect, in fact I wanted the paint to be slightly lighter. Once dry I sprayed the patch with glosscote for the new decals. I found this crazy looking tape at an office supply store made by Scotch. It's not meant for painting as it has very little adhesion. However, for airbrushing it's perfect, especially with delicate parts.
Since CSX only used the nose light and not the one located between the numberboards, I went ahead and removed it (headlight lobotomy) first with some nippers and then with files. Using some Evergreen styrene, I made a steel plate to cover it. I just "eyeballed" it until it looked right and painted it the same color as before.
The number boards were lightly sanded and re-painted white, I also added Microgloss in preparation for the new numbers.
Here is the current state of the model, I'll post more photos when the decals and weathering are finished.