However, Emsingen's entry signal A is out in the middle of the forest, and I do need the machinery to be accessible for servicing. In this case ended up fitting a sheet of styrene over the space, brace it with some wood, and cover the ends with stone sheet.
Placing the cover at the signal showed that I didn't get the cutout for the mast quite right and had to enlarge the hole. I'll put a telephone cabin in front of the hole, so that it's not quite as obvious. Yes, this is actually one of the triple-coil semaphors, so the cover needed to be quite big.
|Cover painted and topped with a thin layer of fine sand.|
The telephone box looks way out of scale. I wonder if this was a N-scale kit...