Here is the 4' by 12' dogbone, using 18" curves.
Using #4 switches, we add a siding accessible from both ends. Note: this siding works like a wye, a type of reversing track. The inside switch and track must be insulated off and wired as a reversing track.
We add a simple spur inside the right loop
Sidings are added to the inside and lower middle, as well as the reversing wye in the left loop.
More sidings to serve various lineside industries. The dogbone in this configuration offers some interesting operational possibilities