>Yes, but not in that photo. I'm not sure why that showed up.
Fascinating! Do you think it could perhaps be a thin oil film then? Looks like it was about to rain, maybe the engine had already encountered some fine spray that washed some oil onto the windscreen ...
Found this trestle just outside of Saltville, Va. The locals call it Tin Bridge, it's located on route 745 which is Old Saltworks Road about 2 miles from Saltville. I believe it is part of the old Virginian line but I may be wrong. The photos are a little dark but I screwed up the camera. Oh well.