Yes,
In the depot (the one destroyed in the 50's), there was a semaphore on the north side of the structure extending through the roof. The pole going up had a ladder attached to it and a rectangular hole was cut in the roof. I do not know exact dimensions, but it appeared to be somewhere in the neighbor hood of 18" x 36" to maybe 24" x 48". The rectangle was long ways up and down the roof, not side to side...
Best I can tell, the roof was "sealed" around the hole, so little to no rain or other water would get inside the frame of the roof. This is only based on the few pictures I have seen, here is a snip of one picture that is not my property...
Casey Akin