There was this engine I like very much which I placed on a hidden staging track someplace awhile ago for "safe keeping" and there were three special passenger cars usually assigned to it which I had been running behind other power several weeks ago.
Well, after a while away from home busy with another project I decided to couple them up but could not find them. Take away lesson. One MUST have cameras at both ends of all hidden staging yards.
Take away #2, hidden staging yards should not be too well hidden.
Take away #3, just maybe, hidden staging yards should have optional illumination.