HO

HO trains

H0 gauge (HO scale) is the most popular scale of model railway in most of the English-speaking and non English-speaking world, in the UK however, OO gauge -with trains built to a larger scale but using the same track as H0- predominates.

In H0 scale, 3.5 mm (0.14 in) represents 1 real foot (304.8 mm); this ratio works out to about 1:87.086. In H0, rails are usually spaced 16.5 mm (0.650 in) apart which models the standard railroad gauge of 1,435 mm (4 ft 8+1?2 in).