Newbie needed torque/moment arm design assistance
You might well be correct about the maximum torque; I'm really no good at figuring things out from real engineering principles because I've never studied anything like that. My reasoning regarding my idea about the maximum point is that gravity, inertia, and friction are pretty much the only forces that you have to overcome. Since the inertia and friction shouldn't change, the vertical position is the one in which gravity would have the most effect. While there's a horizontal component of movement, won't the rails, rather than just the drive train, be supporting part of the weight?
Regardless, I really don't know what formulae would be involved.