Polly Scale ATSF silver would be my 1st choice, then a mix of silver and Stainless Steel for a more "used" look. The older Polly S colors, I haven't a clue. Some people like the Testor's "Metalizer" paints(solvent based), but they may look too "metallic" for N-scale. I'm basing this on the "paint wars" the aircraft guys have in 1/72 vs: 1/144 and 1/200th scales for silver PAINTED aircraft. We won't even play the "natural metal finshes" wars...
PS: I like the look of Tamiaya silver too. Without any weathering, some people say any "silver" is too bright and approximates a "natural metal" finish of passenger cars, but it's your call there. That agruement surpasses "rivet counting" quickly, IMHO. Unless we're gonna display our tiny trains in direct sunlight outside, any color will be subject to layout lighting, and what "looks right" to you. Good luck with your project.
