The Austin Tinplate Trackers track spacing is 4 1/4" between each of our 4 mainlines. Some modules us the 5th track position so we have all 5 tracks on our corners and our lift bridge module. This allows us to be more flexible in our layout design. We also have a pass through yard that must be entered via tracks 123 and 5.
Attached is the track plan for our 5 ft. corners showing track radii and spacing. We used K-Line shadow rail / super snap track. We designed 6 ft. corners as well but our layout geometry would have forced us to build extra 2 ft. modules so we went with the 5ft. corners. Since building these we have not had any issues with trains clipping each other. Those in the club with 21" plus cars and articulated engines run on tracks 1 & 2.
We also have 4 45 degree corners that made a half circle. Two of them together make an 8 ft. square 90 degree corner. I cannot seem to find the diagrams on those corners but tracks 1 & 2 are extended 120's. They are extended by having straight sections before going into the curve. Track 3 is straight 120's. Track 4 is an extended 96 by way of a section of 120 in the middle. Track 5 is all 96's. These modules can also be reversed and create large sweeping 6 curves that all large engines and cars can negotiate with hitting each other.
Hope this helps.
