It looks like a homecrafted wooden slat tank tracks on a double rear axle, but it's such low resolution I can't tell for sure. Via: http://www.owensvalleyhistory.com/el_camino_sierra/page76a.html

Above: Mile a minute Murphy and somebody else on home trainers... competitively. Interesting set up to see who is ahead!

I've seen one other shot of this, I wish I'd saved it., this is a BMW

image from http://www.savetheenzos.com/post/342087498/snowblower-train-corvette-forum via http://friendship-classics.tumblr.com/page/15

For something to see happening skip to the one minute mark, for a close up of the blower, skip to the 5 minute mark, for it ot get moving and make progress skip to the 8 minute mark



the LeTourneau electric arctic land trains has a great write up recently on http://blog.hemmings.com/index.php/2009/11/19/54-wheel-drive-the-letourneau-electric-arctic-land-trains-that-put-australian-road-trains-to-shame/

Above, the Kee Bird, which was the subject of an awesome recovery effort when private funding got it up and running, and moving, but old electrical wiring shorted, and the whole thing burned to cinders on film while a documentary was being filmed, it is so worth seeing!

A couple guys who work as snowmobile mechanics took the stuff that had been laying around the shop and made this .... applause! http://www.automotto.org/entry/snowmobile-mechanics-turn-station-junk-into-snowmobile-chopper/



Via a thread about snow machines on the Jalopy Journal: http://www.jalopyjournal.com/forum/showthread.php?t=229248&showall=1