this bachmann spectrum climax was weathered in about ten minutes, a light coat of cheapo acrylic walmart paint, [i -think- it was buttercup] , along the high dust portions of the model ...all the weathering was done with an airbrush, and no thinning of the paint was done, it kinda spattered on ..
it didn't get much weathering as the era modelled was the 1890s and the loco would have been fairly new yet .. the scale is HO