I lucked up with having just a couple of extra millimeters on three sides to even mount this thing.
It's over two feet away from the edge, so I mounted this to a small block of wood,
lined it up with the turnout as best as I could, then held it into place underneath with one hand,
and with the other hand, ran screws from the top down into that block.
It was not a happy experience.
Sadly, the turnout has always given me grief,
and it never wants to set to the passing siding (thankfully it doesn't get used that way much)
as easy as the other turnouts (all of which are far more accessible).
I'm going to have to do some work to the one of the points,
so the cars want to go that direction better...