Hello,
I have created a turntable for a train in Minecraft create mod. I will send you a link for a schematic download, but first you should know how it works. Only thing you do is by 3 buttons, rest is automatic, but still you should know when to press it. The train will be in normal train station, to start the train, press the button inside the train. Then the train will go to the turn table when it will stop by itself. Next to turntable there are 2 buttons, which are described with signs, one will start the turn table. Then when it is fully turned, the train is ready to go, press the second button labeled TRAIN GO. When the train leaves the turntable, the table will return to its original location, ready for another turn, and the train will return to the train station. Note that the train might get stuck at the rails, just give it a little push and it will continue. Also, the turntable is slow, and has delays, its to stop the machine from breaking up, also if it would go faster, the train would bug out and fall through the moving turntable.