In the same scale standard-gauge trains are modelled on 16.5 mm (0.65 in) gauge track, known as H0. Narrow-gauge trains are usually modelled on 9 mm (0.354 in) gauge track which is known as H0e and industrial minimum-gauge lines are modelled on 6.5 mm (0.256 in) gauge track known as H0f gauge. HOn3 is used to model 3 ft (914 mm) gauge railroads in the United States and uses a track gauge of 10.5 mm (0.413 in).
Manufacturers
Model Railroads