I can pretty much guarantee that Old Faithful is NOT a triploid, but a fertile tetrapolid instead.   It may have difficulty setting lots of seeds as a seed parent because of the physical nature of it’s carpals, but as a pollen parent it’s pollen sets seeds on other fertile tetraploid varieties just as well as pollen from any other tetraploid does.

Seedlings using it’s pollen tend to be late blooming in my experience, and since it blooms late in the hybrid season, one may need to use creative strategies in order to use it’s pollen on earlier blooming varieties, but other than that it makes for a good pollen parent.

Bob Johnson