In reviewing this discussion and my original theory I would make one change. Somebody suggested (I can't find it right now) that the first turn would run through the long siding and leave the first cut at the east end of the long siding, and then the second cut would run through the long siding and leave its cut at the west end, escaping via the crossover. That sounds more logical to me.
Chris raised a question about retainers. I have no idea whether they used them going down the east side, it should be covered in the special instructions somewhere. It's a 1.42 ruling grade and you had one engine controlling around 70 cars. I'm traveling so do not have access to my copies of the special instructions.
Earls comment about a train running over the top without stopping is interesting. In my experience they always stopped for water first, so that they would have time to put more water in the boiler. I suspect toward the end all kinds of different things happened. And also before the drilling boom created the really long trains, there were probably the occasional shorter trains that might have been handled differently.
JBWX