Phase 2: Will a helix help in a tight spot?

The outer loop in the back yard, will eventually go out to the front yard (through the wall that divides the front and back yards)in the distance), cross the driveway and continue around the house, and come back through the front courtyard.

But for most running, I want it all secure and out of sight in the back yard.

Now,  the problem is how to get the track at 21" here back down to the ground? The track goes behind the fireplace youi see, and through the planter at the very back near the iron fence. Here you are looking back down grade from the west end of the fireplace, continuing downgrade east through the planter and then turning south paralleling the iron fence.

The track is at maximum height just this side of the fireplace, and levels out even with the decorative red brick top.

 Looking West at the same "wide spot" where the helix might work to bring the track down the 21 inches to ground level.

There's not a lot of space, but a helix came to mind, so I mocked up something to check it out.

Refining the idea

OK, so I think it might work. Now to make supports to the actual grade, have to tie it back into the main line on the ground.

It took a lot of balancing, and the Aristo joiners are getting pretty tweaked. Looks doable. The track is 8' diameter, and it's pretty close.

I used a 10 foot diameter switch to the main line:

At this point I took Aristo HW passenger cars, USAT streamliners, and container cars by hand (very carefully!) down to check what clearances I needed. I measured 4.5" from the outside rail. Tight, but they made it!

Add rail clamps and test!

OK, add a whole bunch of Split Jaw SS clamps. I actually ran a USAT F unit down and back up this!

Being a little fearful, I took 2 Aristo heavyweight cars coupled together and rolled them down, they worked, although the track flexed enough that the undersides touched the rails a couple of times. Same for the full length USAT streamliners.

Final decision: not the best solution

Looking at the grade and the curvature required, there was just no way long trains would go down this and up was impossible for more than a loco and one or two of cars.

Long cars would stringline.

It also completely obstructed the walkway. I did find a better alternative, but this was a good exercise. It could be done in about 8 foot, and would allow very short trains with short cars to go down.

Going up might be problematic, adding derailments as the locos try to climb the rails on a very steep curve.