I have a coal dump being built and the grade looks to be about 5%+. Now no locos will be on grade, just ore cars pushed up grade, this is for about 24" and then flattens out. Doable as far as working? Don't care if proto typical (FSM kit is fantacy anyway), though a mockup looked fine.
Nothing wrong with that, even if a couple idler cars are needed to spot full hoppers. you could also lower the grade under the dump if your benchwork and layout allows.
This coal dump had joists notched and scenery ramped down to the lower area
If the 5% ramp looks odd, scenery. trees and other means to disguise it will help.
Modeling B&O- Chessie Bob K. www.ssmrc.org
Problem is that the dump ends up on a lake and as it is I eliminated the footings (they could be underwater). At the other end is a switch to the car float so I ended up with aprox 24" of space after the dock which needs to be level.