Is there a compensation for the tight curves in the grade?

If not, we'd have to add something like 0.3% to take into account the curves, and that gets us to 3.5% grades.

As an aside, is there a good explanation why the A1A-A1A configuration is preferred over a BoBo configuration (unless the axle load would be too high, of course); a BoBo configuration would on the other hand also work better in curves due to the shorter wheelbase.