Although I am a 2 railer, if anyone can remember or might even still have a Cleveland Toy Company 24" turntable for Lionel trains, this may be of interest. I got this turntable in 1953. It has a deep aluminum pit shaped much like a barbecue pit of that period. The turntable bridge is a solid block of wood with cast plastic sides having enormously huge rivet detail. It also has two sets of angled ball bearing rollers that rode around the bottom edge of the pit. There was also a wooden block control house with detailed lithographed paper sides and roof, missing when I took this photo in 2004. The drive mechanism below powers a gear on a central post of the turntable bridge. Although powered with a single "D" dry cell battery, it's surprisingly strong and the bridge revolves at 1 rpm. It is a bit tricky to stop the turntable bridge to align with the tracks, but practice makes perfect.
To "scaleize" the turntable, some flex track was cut to fit around the pit bottom for the bridge support rails. The wood block bridge bottom ends were undercut, so the wheels would ride on the rails instead of the pit bottom. No need for any flanged wheels here, even prototype turntable bridges use wheels with no flanges. This also let the turntable bridge stay at the same height as before, to align with the layout tracks.
A strip wood deck was made. Every 4th tie on the pre-fab turntable track was removed so a longer tie to carry the walk way on both sides could be installed. A new control house was scratch built in styrene. It has windows from an old Train Craft tool caboose which did not need them any more. It was turned into a B&O flanger. Nothing goes to waste!
Close up of the new control house. The turntable deck safety railing is from Plastruct.
The odd oversized huge rivets were sanded off the original plastic sides. New styrene siding (.040" sheet) was cut to fit over it. Styrene "T" section stock was used for the braces. More styrene and ABS shapes ladders created the power gantry and pit access. The walkway at the top of the gantry is strip wood. On prototype powered turntables 600 volts is fed to the bridge for the traction motors below.
The engine house is in place, with its approach tracks and inspection pits. The pit bottom was detailed with tan paint for concrete, some ballast, dyed sawdust and some lichen for weeds. The pit walls are white, with black lines marking panel joints.
A final paint job and B&O 1930's style lettering for Safety First.
The original tethered control box from Cleveland Toy wasn't used. The turntable was hardwired to this control panel. The engine house and its surrounding tracks have a separate power supply. The engine house approach tracks are wired for transferring a move between it and the yard panel.
Here is the final setting of my 51 YO Cleveland Toy Co. turntable.