5.5 mm to 1 foot scale (1:55.4 or 1:55) is used for modelling narrow gauge railways.

[1] GEM produced kits for locomotives and rolling stock from the Ffestiniog and Talyllyn railways.

The tooling for the GEM kits was purchased by Malcolm Savage in 1996 and he reintroduced and upgraded the range.

More recently, 3D printing techniques have expanded the range of available models even further, while in the USA there's a quietly flourishing 3' gauge modelling fraternity, using OO track and mechanisms.

Historical and contemporary figures, buildings and accessories are all readily available from a variety of manufacturers.