Hi,
This stub double slip started out as a regular #6 stub switch. The track from the right foreground goes to a door in the basement. The track from the left foreground goes to the other end of the back yard. The track exiting the left side of the photo is the 13' loop to connect to the track in the left foreground.
This was all done in 4.75" gauge. I printed there photos in Modeltec Magazine with an article about the turnout. Unfortunately, I can not locate the other three photos.

I later added a loading track to the front yard. That is the track exiting the right side of the photo. It just laid out right into the existing stub turnout. With a 10% grade on the side of the house getting to the front yard, no running could be done on the loading track.
To keep the ties in place, the ties are connected on the left side with a 1/8" x 1" aluminum strip. The rail on the right side is correct for 7.5" gauge. It was used to support the ties on that side.
This first photo shows the turnout set for connecting the loading track to the foreground loop track.

This second photo shows the turnout set for connecting the storage track to the basement to the 13' radius loop track.

This third photo shows the turnout set for "normal". It connects the basement track tot he loading track and completed the back yard running loop.
Eventually, I converted my track to 7.5" gauge and dual gauged three of the four routes in the double slip. Only the route to the 13' radius loop was left 4.75" gauge.
I may be contacted at edgarcorny@dougsrrshop.com