Oh my god isn't she gorgeous! This is the McKeen Motor Car and she's a pretty misfit and I love misfits more than just about anything else in this world.  She was originally gasoline powered but now sports a Caterpillar diesel engine. In fact, I do believe it is the same CAT 3208 motor I run in my school bus RV conversion.  Hmm, now that is giving me ideas . . .

From Carsonpedia:

In the early 1980s the Nevada State Railroad Museum opened up in Carson City, and started rounding up all the old V&T equipment they could get their hands on. #22 was one of the pieces they were interested in, and it took over a decade of negotiation before Al agreed to donate the car to the museum. On April 22, 1996, #22 was torn off its foundations once again and made the move a few blocks south to the railroad museum. Restoration work started almost right away, but a lack of funding made sure that it would be slow-going.

As of February 2009, exterior restoration is nearly complete and finishing touches are being put on the interior.

There's more information in the Railway Preservation News Forum and a bunch more pictures at AroundCarson.com.

[Thanks Dick!]