... minimum radius? Toy trains traditionally go down to 15" radius but unless you will be running only old toy trains I don't think you can sensibly go that sharp. Perhaps a suitable absolute minimum would be 450mm/ 18" radius? To get the easiest possible radius in the shortest turnout you need to select the non-prototype model switches in the list, and a generic type V-crossing. 2_011146_480000000.png Using the shortest 1:24 model switch and generic 1:6 V-crossing you can get this crossover: 2_011147_280000000.png 750mm radius in the outer double-track and 700mm in the inner double track. Generic V-crossings. The turnout radius in the outer turnout is just over the 18" limit at 464mm/ 18.3". This seems to be about as tight as you can sensibly go with kit-built models, and even then is likely to mean carving lumps out of them for loco bogies to swing, carving behind splashers for extra side-play on wheels, wires across the buffers to prevent locking, etc. Against ...