Bernd wrote:I should have mentioned that I was looking for an approximate figure. I was wondering if you had a piece of flex track what would the minimum radius be before you either broke the track or it was to tight to use realistically. I think I have my answer, 12 inch would be minimum. Thanks guys.
Bernd
It depends what you want to run on your layout.
Some HP Products engines would not run on that. 2-10-4 and 2-10-2 have minimum radius of 18".
NEM has this standardized (NEM 111), but it depends on the vehicle size and type of the track: main line/branch line/industrial siding.
It is a good standard, but 95% of the TT scale track manufacturers ignore it.
Use the recommended radii and it will be OK. Here they are in German version.
http://www.morop.eu/de/normes/nem111_d.pdfYou can find it translated somewhere on the board, I think it was in the topic about Kuehn's track system.