5.5 mm scale

5.5 mm to 1 foot scale (1:55.4 or 1:55) is used for modelling narrow gauge railways. 12 mm (0.472 in) gauge track is used to represent 2 ft (610 mm) to 2 ft 3 in (686 mm) gauge prototypes. 16.5 mm (0.65 in) gauge track is used to represent 3 ft (914 mm) gauge prototypes.

5.5 mm scale

5.5 mm to 1 foot scale (1:55.4 or 1:55) is used for modelling narrow gauge railways. 12 mm (0.472 in) gauge track is used to represent 2 ft (610 mm) to 2 ft 3 in (686 mm) gauge prototypes. 16.5 mm (0.65 in) gauge track is used to represent 3 ft (914 mm) gauge prototypes.