What is the smallest radius curve the Spectrum Shay will run on.
what scale?
HO - probably 18" easily… maybe 15" if you take it slow
N - no idea, though probably whatever radii are the equivalents of the above…
HO runs fine on 15" curves here.
My HO Spectrum 3-truck Shay always derails on my 15" radius curves, but those curves also have an 8% grade [:O] I suppose that it would probaly run better on a smaller grade, but I would recommend 18" curves if possible for best performance.
I have 2 Spectrum Shays, with 15" radius and 8-12% grades. They run excellent.