Editing O scale (section)

===O-27 gauge===
''O-27 gauge'' is variant whose origins are slightly unclear. Some historians attribute its creation to [[A. C. Gilbert Company]]'s [[American Flyer]], but [[Ives Manufacturing Company]] used O-27 track in its entry-level sets at least a decade before Gilbert bought Flyer.

The modern standard for O-27, however, was formalized after 1938 by Gilbert, who scaled the locomotives and rolling stock to [[1:64 scale]]. After World War II, this practice was continued by [[Louis Marx and Company]], who used it throughout its product line, and [[Lionel, LLC|Lionel]], who used it for its entry-level trains. O-27 track is spaced at the same width as regular O gauge track, but is slightly shorter in height and has thinner rails than traditional O gauge track. A shim underneath the O-27 track enables the use of O and O-27 track together.

The O-27 name comes from the size of the track's curves. A circle made of eight pieces of standard 45-degree curved O gauge track will have a {{convert|31|in|mm|sigfig=3}} diameter. A circle made of 8 pieces of 45-degree curved O-27 track is smaller, with a {{convert|27|in|mm|sigfig=3}} diameter. Full-sized O cars sometimes have difficulty negotiating the tighter curves of an O-27 layout.

Although the smaller, tin lithographed cars by American Flyer, Marx, and others predate the formal O-27 standard, they are also often called O-27, because they also operate flawlessly on O-27 track. Marx may have dedicated its entire line to O-27, but only the [[Lionel Corporation]] remains to produce O-27 track and trains. Its tubular rail is a standard of the tinplate era.