The calculations for compensation of curves on a grade were posted on either this or my other "home" forum.
The formula is 32 ÷ radius
I have a 45' long grade on my layout that's at a constant 2.8% grade. However, there are several curves within that incline.
The first two each have a radius of 34" and as horseshoe-type grades, extend somewhat beyond a half circle each.
The third curve is the entry into an "S-curve, and relatively short, with a 40" radius. It's followed by two somewhat longer reverse curves, both at 48" radii.
That means that if I run a train as long as that entire grade, the effect of the compensation for the curves shows it to be the equivalent of 6.82%.
I have run such a train on that grade (4 locomotives of varying types and in varying positions with the train, plus 71 freight cars, of various types and weights) but could not reach what would be the actual top of the grade, as the partial second level of the layout had not yet been built.
The train occupied about 42' of what would eventually be the finished grade to the partial second level.
In day-to-day operations, I would more likely run trains of 20 cars or less, and in almost all case, at least two locomotives...more if necessary.
Wayne