If you're using open grid or L-girder benchwork, in conjunction with plywood sub-roadbed on risers, it's fairly easy to introduce superelevation, along with natural easements into it.
With the risers attached to the sub-roadbed, but not to the benchwork, raise the sub-roadbed to the desired elevation, then fasten the risers which are just outside of either end of the curve to the benchwork. These should be perfectly perpendicular to the benchwork, and the roadbed throughout the total length of the curve should be temporarily supported by these two points. Now, locate the riser which is closest to the half-way point through the curve, and carefully raise it until the centre-point of the curve is level with the two endpoints. If your curve is on a grade (which most of mine are), then the riser and roadbed should be raised only far enough to keep the grade fairly constant. You can use lines and levels to determine this, but it generally works just as well to just "sight" it. When you have it at the proper height, make a reference mark on both the riser and the benchwork at the point where they will be fastened together. Now, grasping the bottom end of the riser, pull it to the outside of the curve. One of two things will happen: either the roadbed on the inside of the curve will drop, or the roadbed on the outside of the curve will rise. It's preferrable to have the outside rail higher, so adjust the vertical position of the riser so that the reference mark that you made earlier lines up on the inside of the curve. Adjust the amount of superelevation by eye, then, using screws, fasten this riser to the benchwork. Now, roll a train through the curve. The individual cars should gradually heel over as they enter the curve, and gradually return to vertical as they exit. If it looks good at the speed that you'd normally be running the train, then you're almost done. Otherwise, adjust that middle riser until you are satisfied. Then, with the test train safely out of the way, work your way around the curve, fastening the remainder of the risers to the benchwork. Do not attempt to move them either to the inside or outside of the curve, or you'll upset the natural easements on either side of the centrepoint, simply fasten them in place where they fall.
Here are a few examples, although the effect is most noticeable on a moving train.
The effect is pretty subtle here, as this curve (on a grade) is posted at 35 mph for freights and 45 mph for passenger trains.
This one is a little more obvious, even though the speed limit through the grade here is 35 mph.
This is the same curve, as viewed from the opposite end.
Even this curve, through the industrial area of Dunnville, is superelevated. The speed limit here is 20 mph for freights, and only 10 mph for passenger trains, due to the tight curves, and again, it's on a grade.
Wayne