A couple years ago, I read an article by Jim Barrett where he described building a concealed opening in a mountain.
When designing my new layout, I found that I had to locate a switch track not only under a 6' long tunnel in a mountain, but right in the middle of it!
I am so glad I followed Jim's advice by building a rather large removable panel just in front of the switch track! My wife helped by suggesting I use magnetic latches to hold the panel in place.
After two years, today I found that I needed to actually remove the switch track under the mountain for some maintenance as there was a short that I just couldn't figure out.
The track was removed, repaired and re-installed.
Here are a few pictures: