hi goedel -
thanks for that link - it all looks a bit complicated for me! i think ill lay the curved tracks loose on the boards, then put 2 of the longest carriages ill run on the curves and space the track apart sufficiently so that the coaches pass each other without hitting! ... my tight curves will all be hidden under tunnels anyway, so they wont be visible!.
that peco track gauge looks handy for the straight traicks though, thanks for posting that - and its so cheap so ill definitely buy one!
thanks again folks!, what a great site this is!