Here some of my steam locos on my hand-made turntable (well, there are also a couple of non-Lima locos, I hope not to offend anyone..):

Yes, due to layout dimensions, I need an asimmetric solution. So I take a paper cake-plate, put on a thin wood panel, and I made an arrangment to let the turntable rotation. Then I create the tracks terminals, one by one in the required length (one was then modified after the purchase of the lok SNCF 141, the longest one...). Track terminals were then soldered to the control panel, where I used three positions switches connected to a green led (one led for each terminal). I have 7 tracks, so I used 4 switches. With one switch, I can control 2 near tracks, giving power to the upper or bottom track, or to no track (by using the middle position of the switch). Then I also added a red led to check the reverse track polarity; in fact, as you can imagine, the turntable may work in proper way only if the polarity of the rotating track is the same of terminals (when the polarity is reverse, the red led is switched on; so in this case,to avoid short circuit, I simply push the loco out from the turntable to the track; ok, is not the best of realism, but it works).



Here the result:

..and here the control panel with switches that let me operate the turntable supply (the green led switches ON when the terminal track is powered):