Anyone ever use them? i was browsing Through my Mico-Mark Catalog and i came across them. Says they have them in 3 sets of 3 pens for weathering.... Track Colors - Rail Brown, Railroad Tie Brown, and Rust Structure Colors - Aged Concrete, Weathered Black, and Roof Brown Earth Tones - Earth, Mud, and Grime The sets are $7.29 each for 3 markers (1 set), says there 1/3rd of a fluid ounce.... I was thinking about getting each set of them and trying them out, the pic they show next to them shows a track weathered with the Track Colors set and it looks pretty good. Anyone ever used these before? What did you think about them and how well did they actually work? How does it compare to airbrushing weathered track?