Are there 2 sizes in N Guage? Several years ago I purchased what I thought was an N guage engine model of the Jupiter. I was cleaning out my folks house and I found it but it was in bad shape , broken etc...  I wanted to replace it so I found 1 on Ebay in the original box. I bought it however its smaller than the one I had. The box says N guage but it's much smaller. Are there different sizes within a guage? I'd like to find a replacement for mine.