Ok, Mark and Marc, I swapped out the photos above. I was able to add a passing siding by moving the start point for the grade and increasing the initial grade to 4.4%. That gives a total rise of 6.6% over the length of the overpass and the 2 grades. I also added a second siding inside the reversing loop. I could be wrong, but I think this is as close as I'm going to get to the original and keep the grades reasonable for the trains that will be run. The sidings can be lengthen by adding a curve to the ends, but that's not prototypical, so I didn't do that. Those and the top end of the passing siding can probably be smoothed out using flextrack during actual construction.
Oh, and the overpass is 6", so that might have to be adjusted too depending on the roadbed and sub-roadbed used in that area. 
