From: utzoo!decvax!harpo!seismo!rocheste!heliotis Newsgroups: net.railroad Title: Re: HO scale query - (nf) Article-I.D.: rocheste.391 Posted: Mon Jan 10 09:44:05 1983 Received: Tue Jan 11 03:31:37 1983 References: uw-june.233 I recently went to a model railroading meet, and asked about the difference between "O" and "O27" scales. I was told that the only difference is in the height of the rails (I forgot the reason). O27 is newer. The "27" refers to the radius of the curved track. One can use the same cars on either system, I believe. Jim Heliotis