I don't know if it's my lack of exposure to steam engines in general or is the 765 REALLY a special machine.
I've been around a small number of steam engines in my 57 years but I've NEVER seen (or at least been aware of) perfect smoke rings coming from the stack.
This smoke ring floated above the 765's stack on Sunday 19 August. We were at the Bridgeview B&B in Marysville Pa. At the time this was taken, the 765 was backing the train towards Enola yard after the end of the Noon run.
A prefect ring!
Artie