O Gauge Coarse Scale
Coarse Scale is something of a misnomer. O gauge models were built to a range of standards with the toy-like products of Hornby, Mettoy early Marklin, Bing and others. Whereas Bassett-Lowke Leeds Model Company and Milbro worked to a more prototypical standard.
O Gauge was Common in the 1920-1950 but is much less so these days with most modellers electing to go for the smaller scales. The exception to this is, of course, the Collectors of older trains and some of the new products by ACE ETS Lionel and others who build models to a very high standard but their running gear is to Standard Scale enabling them to run on a wide range of track work that the ultra-fine models will not tolerate.
The "Hornby Railway Collectors Association of Australia is well known for this side of the hobby and a link to their web site is in the links page The following Gallery pages and videos illustrate this aspect of the Hobby
OO Gauge Collectible Trains
OO/HO Collectible is something of a misnomer also as many folks collect many different types of models
However, most people in the model railway field would think of Hornby Dublo, Triang, Marklin, Bing, and Early American Models such as Rivarossi & early Athearn to name a few as classic collectibles.
Mostly these were made from the toy market but with a nod to accuracy as time went on the level of accuracy improved and the models became more scale models until today when so many model trains on the market are not toys but high priced ultra-accurate models of the real thing
However, it is interesting to look back on some of these early models that still stand up to scrutiny and are still running after 60-70 years since manufacture. Their robustness may well outlive the finely detailed plastic models of today