Backgroud: I am writing a short story which takes place in rural southern Georgia (USA) and includes a lot of aspects of the railroad because railroads are historically important in this area of the country. I found in north-central Florida an interesting structure by the side of the traintracks which appears employed in some capacity to railroad business but I don't know exactly what it does. It is marked as the "Newberry D-D" on it in several locations and Newberry is in fact the nearest town to its location. There is a concrete block building and a pre-fab (newer) steel structure behind it which I assume to house electronics for communications or something. Can anyone help tell me more about these structures?
I have tried researching a lot of different information about railroad operations however most of what's online is about old-timey trains and little is germane to current operations and since I don't know the name of the structure, I can't really goole it either.
Below the cut is a photo of the structure in question:
Thanks so much for your help!