Something to consider. If in designing your track plan you find your self dealing with too steep of a grade here is something to consider.
As a train starts up a grade it is gradually accumulating increasing drawbar load as it rolls up the incline. Because there is not that much of a load at first you can use a steeper rate of climb for the lower portion of the incline. Conversely, working on a fixed length, since you have achieved more height sooner with a steeper initial grade, then as the draw bar load increases further up the grade, you can use a rate of climb that can now be less then you may have originally figured.
If you have never cheated this way it may take some experimenting before you figure out what works best for your application.
Car weight, wiper drag, degrees of curvature. construction, length of train, etc. are variables that will affect your design.
As you get comfortable with this approach your grades may start to take on a convex sort of profile. You need not go from say a 4
% grade then angle to a 2% grade.
Consider splicing your entire grade subroadbed together. fasten the first 18" or so flat to the lower plane then clamp the last 18" +/- flat onto the next level. Now the entire actual grade subroadbed is fully floating.
Cut yourself a successive series of increasing height risers or spacer blocks with the same incremental increase.
Now, try spacing them closer to one another at the lower end of the grade and then gradually space them further apart at the top of the grade.
What you re doing is constructing two vertical spiral easement curves. A concave vertical easement at the lower level and a convex easement at the upper level.
This is very effective in getting the train up the hill. Coming down is not an issue.