How about this??
If I start the downgrade at line A there is at least 30 feet to line B to change 6 inches... I don't know what % that is but it would seem like enough room. Also the track coming off the turntable is conected only to the staging yard and I can make that whole RH/TT area any elevation it needs to be to make it work. I can lower the mains 3 inches and raise the turntable 3 inches if needed..
In the inset the line off the Y is nothing more than a reverse loop and from what I can see needs to drop at least another 5 inches between C & D which is about another 10 -12 feet .. might be a bit steep but it should work.
From what I can tell the turnouts that concern you are on the main before the underpass between the 2 red lines .. these are there to cross from track to track and can be moved to anywhere... actually the complicated slip switches are really not needed...and most of the turnouts except for the one leading to the Y can be relocated ... open grid bencwork should make the elevation changes pretty straight forward...
