Charles H is absolutely correct. LIONEL , in fact, made 'OO' scale
equipment in the Great Depression. This included a scale NYC "Hudson", which is interesting because they also introduced a
scale 'O' scale "Hudson" at this time. Both of these locomotives,
command astonishing prices on the "Collectibles" market.
They did not produce any 'OO' scale equipment after World War Two.
Carl Appel, now deceased, is probably the first well known
model railroader to emphasize prototype operations. His two
"NORFOLK and OHIO" model railroads were both 'OO' (i.e. 4mm=
1ft. on 19mm gauge trackage). Allen McClelland, Koester, and
others all credit him with leading the way. He was a W.V. jeweler by profession* , and used LIONEL 4-6-4s and Famoco 4-8-4s for
passenger and manifest freight service. He scratch built exquisite
N&W and C&O articulateds and other locos, when he needed to.
His fantasy empires were based upon the N&W and C&O operations in the Appalacians.
His last pike featured the Williamston, W.Va. N&W facilities which
were on a mid river island, among other things.
The scale may have not had many followers on this side of the
pond , but its follower(s) had a profound effect upon revolution-
izing how model railroaders approached the concept of a layout.
If you GoogleUp the "SCALE 4 Society", you will see that
that protoscale 'OO' is alive and well in the British Isles, and the
76:1 scale is very well supported by a host of models of all
kinds. LLedo's "Trackside" series is die cast vehicles made in that
scale, so the mid twentieth century and earlier epochs are
well covered. Protoscalers, regardless of scale, attempt to
model the exact relationships appropriate for that scale. Many
widely accepted train components are used throughout the
world that are not true to scale. Most notably by toy train makers,
but in some places the errors have become institutionalized
(e.g. 'N' scale in Japan, and U.K.), to the point that only by
going out of ones way to become a scratchbuilder, can one
have true scale components of ones prototypes.
Good-Luck, and yes, LIONEL manufactured 'OO' scale trains
at one time, - PJB.