Well I don't have too much in clockwork but here are a couple of "fun" sets...not too rare but fun anyway.
Here is a set called the Red Flyer...its Marx from the late 40's.
Here is a late Marx set, from the 70's. I love the motto on the box (top left)..."We make it...It can take it!"
All plastic, including the track, but O gauge nonetheless.
Best Regards, Don McErlean