Long time ago, I posed some MTH (Proto 1) locomotives on a track set in the side of a snowbank as a sor-of-diorama re-creating a plowing scenario: a couple of Conrail diesels pushing a Premier plow, and a Big Blow pushing a Jordan Spreader plowing snow off the side of a steep drop-off.
One precaution I took was to sit the equipment outside on the porch, allowing it to come down to ambient air temp before sitting them in the snow (and brushing enough atop them to look like they were actually running in it), Once done with the photos, I brushed off as much snow as possible with a soft paintbrush, then sat them inside to bring their temps back up to room temperature (my house has forced-air heating and tends toward low humidity in winter).
No ill effects or traces of oxidation were noted afterwards. If one were running indoors-to-outdoors-to-indoors during a snow event, it would take a bit of doing to compensate for the fact O-gauge equipment is not weatherized.
---PCJ
