A friend forwarded this link to me. I don't recall ever seeing this on NAT, but my apologies if it's been posted before.

It shows a video of a screw-type mechanism for moving vehicles -- in this case a tractor and an auto -- over snow and ice. Probably shot in the 1930s. The undercarriage replaces axles and wheels in the winter.

I vaguely remember the concept being resurrected in the 1980s. Seems like there was an article in Popular Science or Popular Mechanics, and that vehicle also could move through swamps and mud..

Fascinating concept and a real kick of a video.

I'm wondering if any of this is preserved in museums anyplace. Ford, maybe?

http://forum.treasurenet.com/index.php/topic,213971.0/topicseen.html

Update: Here's a site with video again, plus some background info. You'll have to scroll down maybe one screen to find it.

http://www.absolutemichigan.com/dig/michigan/motoring-through-michigans-snow/

We in the South are both fascinated and repelled by snow. Roger Carter, a crop consultant in central Louisiana, sent me this video link initially.