I've wondered about this tarped car since it showed up one day several years ago. Now I know.
Here's a link to a story at the Tacoma News Tribune.
Northern Pacific Dining Car
Photos and video clips as well as a story at the link.
Depending on how often you've visited the TNT site without paying, you may not be able to read the piece. In a nut shell a Dave Burns owns the car. Moved it from Easton, is trying to restore it. Tacoma Rail owns the site it's currently stored on and now needs that site, so the car must move. Of course Dave doesn't have the funds to move it again and is looking for help.