The hole is cut! What have others done to install their turntable? I'd like to learn from others experience before moving to next steps. What worked, what didn't? What did you use for support? How did you insure the turntable rail top matched the lead or radial track? Thanks for the tiops.
I wanted my 90'er slightly elevated so that the locomotives would not accidentally roll into the pit with the bridge no lined for the lead. So, I placed several 1/8" shims of vinyl commercial underlay under the lip in several locations, say about every 2-3". This arrangement meant that I had to create a slight grade up to the bridge lip, but with Code 100 Atlas track, it also meant that I had to create two parallel grooves for the tieless rails to use as guides and so that their top surfaces matched the smaller code rails on the bridge. I used epoxy to keep them in place in those two grooves. The grooves are shallow, perhaps 10 thousandths, and were created with a thin grinding stone in a Dremel type tool.
However, if your hole is slightly smaller than the outer diameter of the pit lip, that should suffice for support. You needn't build a cradle or anything as the lip is sufficient to support the TT and a good sized locomotive.
Follow the instructions about arranging the lead and any radials, including those in the bays of any engine house. You want the optical eye in a place where it won't be used as a radial, and you want the two dead spots where the rails split to be roughly 90 deg from the lead.
Since my approach tracks to the turntable were already mounted on Woodland Scenics Foam Track-Bed, I took a sheet WS foam road bed, cut out an appropriate sized piece from the center, and mounted the turntable through the hole that I cut in the foam sheet. That assured that the bridge track on the turntable would be at the same height as the approach tracks.
I also used CA cement (super glue) to secure the rails of the approach tracks (as well as the round house tracks) to the lip of the turntable. It was not enough to rely on the rails sitting securely on the lip of the turntable without some form of adhesive support. The rails had a tendency to move vertically and horizontally out of position.
Pay attention to the position of the "No Track" area, as well as the indexing LED. The No Track areas mean just what they say, and make sure the indexing LED is half way between track locations.
Also, with the larger one, you need to realize that you are limited to 60 positions. Each track is going to use up two of the positions, one for aligning each end of the turntable. If you're planning on more than 30 tracks (which I did, remember to count the approach tracks), a trick I used is to align tracks across the turntable. When you install any radial tracks, make sure they form a straight line with the turntable track. Install one of the tracks and set the table index for it. Lay the track directly across from it, aligning it on this mark and just tacking it into place. Swing the table to align the other end with the first track and make sure the tracks both align. When properly set up, you should be able to sight across the two tracks with the table track in the middle, verifying it's a perfectly straight line.
I have 2 of the Walthers turntables and use Midwest HO cork roadbed. To match the height of my tracks I used a strip of the roadbed wrapped around the turntable pit and glued to the subroadbed base. I use Walthers code 83 flextrack and just cut back the ties as they cross the pit flange. Everything matches up perfectly.
Thanks for the tip. I have a Walters HO 130 foot turntable that will be installed in the next 2-3 months. I am using 2 sheets of 1/2 inch plywood for the benchwork. I am using cork roadbed for the mainline and passing sidings. I use N scale cork roadbed for the industrial spurs. I have purchased sheets of cork roadbed for the yard but have not begun to install it. I am concerned about the height of the turntable pit and the approach tracks and roundhouse tracks. I hope that the cork sheets will be of the appropriate height for this. Any ideas?