Here are a few of my favorites from the windup fleet:
1912 Ives:
1922 Ives No. 6... nothing rare, and has a broken pilot, but is a favorite because it is such a nice running locomotive. I bought it with a motor that had exploded (not unusual when something turns loose and a fully wound mainspring unleashes all that stored energy at once) and did a lot of work to it to get it running. The governor was broken, so I replaced it with a modified Marx governor. By happy accident, it runs relatively slow and for a long time:
1936ish era reversing Marx Commodore Vanderbilt. It was a "train wreck" that I restored some years ago, given to me by one of my Marx friends. These early Marx locos with the die-cast drivers and screw-in key are nice running locomotives:
Marx Canadian Pacific 3000 - not only is it a hard to find locomotive, it's a treasured gift from (another) Marx friend of mine that also frequents this forum:
One last one, a custom I made from some Marx 401 windups... my 1203 Marx Triplex. Yes, it has three Marx windup motors in it. It will pull quite a few cars around the layout:
OK, that's all for now. It's hard to narrow down distinctive or favorite windups to post!