A side door into one of the roundhouse bays. Note the "Empty" and "Full" signs: I'll let you know if I ever find out what it is to which those signs refer.
Here's the track on the turntable of the roundhouse. The operator in the little green shack would rotate the turntable until its tracks lined up with those of the selected bay. Since some engines could not move in reverse, a turntable would sometimes be used to turn an engine arouind and put it back on the track from whence it came.
