My ABBA set of Santa Fe F7's.... I'm modeling '72, the last two years of F7's in passenger service on Santa Fe, when the remaining F's were leased by Amtrak before the SDP40F's arrived. While not 'beat', the F's sure weren't getting the TLC they did pre-Amtrak. If you study photos, one of the most outstanding issues is that the silver truck overspray stopped abruptly, and the continued 90mph running dusted them up big-time. Combine that with the usual dings and red paint fade, and this is not the stock appearance. They still got washed periodically, so the contrast between the sides, roof, and trucks is abrupt. I've been tinkering with these forever; first the Kato shells, then repainting and redecaling, additional details, spark arrestors, lift rings, all-wire handrails, finally taking off the skirts and putting on GMM steps. But its taken me 20+ years to finally go through with what I knew I eventually had to do to make it 'right'..... or at least what is 'right' in my eye... The weathering is a three-step approach; first a diluted acrylic wash of 'earth' on the trucks; then a touch of chalk soot/black down the center of the roof for exhaust and where the washers didn't seem to reach; substantial grime between units, finally a heavier dusting of 'dark earth' on the trucks and pilot, along with that characteristic "bow wave" that seemed to happen to an F-unit at speed. I'm sorry, to me this was like painting a moustache on the mona lisa.... I've been very reluctant to do it, but I think it came out OK. Finally, after about 20 years, I think I done with this project!