What is the difference between 0-27 0 and the other 0 guages

Thanks for the help. It seems a bit confusing but I think that I got the idea. At least I should be able to figure out which track I need. I will probably do what you suggested jaabat and keep the 0-27 I have and just replace the curves with 52 so that I can run my new locomotive.

Thanks again
emmar