Minimum Radius of a Helix?

[zgardner18]

QUOTE: Originally posted by pkeppers

Typically in HO 32" of radius equals one percent grade in terms of increased pulling resistance. I’d recomend that after using this formula on your helix and non helix track that the compensated grade in the helix be about at least 0.5% less than compensated grade outside the helix.

I have run helpers up my helix, just to see if there are any operatiional problems, even though it’s not the ruling grade and have found there is no problem, even on 40 car trains but I still dont recomend doing this/

Like you, my plan was to use helpers for my helix as well as the helper gredes but nonetheless, I still am set on a helix.