Sinclair, what I have there is G by Aristo-Craft, 0 by Marx, 027 by Marx, S by American Flyer, H0 by Athearn, TT by Lionel (a non-powered 1/120 scale they offered several years back), N by Life-Like and Z by Marklin.
Incidentally, Z is no longer the smallest electric-powered scale: there is now "T", about 1/2 the size.