I have laid quite a bit of the ME weathered track. I was able to solder it without having to remove the weathering, and locos will run down the rails with the weathering still on the railhead.....I hope this helps.
Don Z.
Research; it's not just for geeks.
Modeling B&O- Chessie Bob K. www.ssmrc.org
see stuff at: the Willoughby Line Site
The weathering is a chemical patina, not a paint, which is why it is not an insulator. In fact Micro Engineering sells the chemical in bottles so you can weather your own track or turnouts -- having said that it is difficult to match the deep color of their preweathered track by applying the patina fluid. Some nickle silver rail that Peco uses turns green first!
Dave Nelson