HO-gauge railway modelling is possibly the most popular scale around, and as such is one of the best known, needing little introduction. It has huge support from model manufacturers and possibly the widest geographic spread of supporters.

HO-gauge is 1:87 ratio scale and converts to wargaming scale as 21mm, but fits comfortably with the actual wargaming scale of 20mm models.

Mainstream manufacturers (e.g. Airfix) often label their products as HO-OO and HO/OO scale, which is a misnomer as no such scale exists. The tradition seems to have evolved from a misplaced acronym function, in that it could stand for “Half Of OO-scale” hence the scale code pairings. OO-scale at 1:76 (24mm wargames scale) is significantly different in size to HO, but it’s certainly not a half scale to the larger size.

Creating new models for HO-gauge is difficult due to the scaling ratio, and as such there seems to be little direct support in the small and home-based manufacturing industry.

(page incomplete – more to follow)

Related Reading: