I have a three or four car train of lightweight MPC era and modern stock, with a lighted caboose on the end. This soon shows any problems with string-lining etc. and I don’t seem to have those problems here.
The Hudson is definitely the limiting factor, with its long tender and oversize front pilot wheels. However the key seems to be, minimising the deflection. As the pilot is on the O36, the loco is already turning on the O72 section - it won’t handle the transition from straight, to O36 directly, and even straight to O42 is pushing it. It will handle simple O48 curves, though, do the critical value is obviously somewhere around 45-46”.
If I had the space, I’d definitely go O72-O48-O36, it looks better and further eases the deflection.
