How neat to have seen that. You're right, turntables and roundhouses are rare and to find one in its native state is something special.
I so miss that sense of open discovery and uninhibited exploration that was commonly found decades ago. Railfanning is just not as much fun today. These days there are signs, fences and surveillance cameras everywhere. Too, more people are suspicious of people taking train pictures. A year or so ago someone called the railroad on me as a stood at a highway crossing waiting on a train. A railroad SUV pulled up and parked, but no words were exchanged. I think the Supervisor saw me, an aging grey-haired guy with a "real" camera standing in a safe spot and knew I presented no threat.