Ever since I added a trolly line to my layout in 2017 I've been trying to figure out a way to include the line as part of the layout's main two circuits. The only thing that needed to be figured out is where to run the mainline currently sharing the trackage needed for the project.
I ended up having to make a custom cross section and add a variety of turn outs to one side and move part of the mainline over. This also allowed for the curves to be widened for larger locomotives operating on the layout.
Some tests revealed that the new line not only could support street cars and trollies but also small trains to change it up a bit. The new track relocated some shops to a better position too.