Winter railfanning

Only CSX Geeps make certain badly peeling SD40-2's look good. Do they paint rust onto the units? How does it get so bad?

I belive it is so bad on the RoadSlugs because they had to spread concrete? over the engine doors, and walls of the nose, and engine room areas. Also they had to remove the fans on the top of the locomotive and place concrete in the area of where the prime mover used to be, to wiegh it down. All the engines are, are really dynamic breaks, traction motors, and electronics with a cab and fuel tank. The fuel is put into both engines, even though the mother is the one that uses that fuel, and when the mother runs low, the slug pumps fuel into the mother's tank, through a series of lines and cables. Cables, and a fuel line, are connected on the rear platform of both units.

But CP has Geep Road Slugs with a simialr diea and they don't even come close in the looks department!
http://www.railroadforums.com/photos/showphoto.php?photo=27148&si=1127

Yes, but CSX applied concrete, or somesort of cealent or something, to the sides to remove the doors, and the roof and nose area, which is the reason for the paint problems, I belive.