Spectrum, 4-4-0, 2-6-0, 2-8-0 .
Hi "Engineer" !
My spectrum 4-4-0 runs LGB radius R1.
But to get it, you have to modify the front wheel bogie.
I just placed it about 3 millimeters mor to the front, so the wheels will not touch the cylinders.
This modification does not affect the appearance of the loco, but, frankly spoken, to go through R1 looks ugly!
I only did this, to make the loco able to reach some narrow stands.
Udo
My 2-6-0 and 2-8-0 run on 6' diameter curves (R-2) on my indoor layout.
However there is a significant slow down while the locos travel these curves.
jb