HOn30 (also called HOn2½, HO9 and H0e) gauge is the modelling of narrow-gauge railways in HO on N () gauge track in 1:87 scale ratio. Definitions The term HOn30 (and sometimes HOn2½) is generally used when modelling American prototypes while H0e is used for European prototypes. In the Britain the term OO9 is sometimes used. All these terms refer to models of narrow-gauge railways built to the world's most popular model railway scale of HO (1:87) but using a track gauge of —the gauge used for N scale models of standard-gauge railways. OO9 refers to OO scale, 1:76.2, models on 9mm gauge track. Although the track gauge is 9mm, sometimes N scale track per se is not used because the ties or sleepers are out of scale and too close together. HOn30 track is available. HOn30 HOn30 is often used to model the gauge railroads in the US state of Maine. The first HOn30 / HOn2½ ready-to-run (RTR) brand introduced in the US was the AHM MinitrainS, initially manufactured by Egger-Bahn and later by Roco and Mehanoteknika Izola, also known as Mehano. Perhaps the most fascinating part of HOn30 is that RTR models are still scarce. One exception is The MinitrainS line that has recently been upgraded. H0e H0e is a gauge defined by the Normen Europäischer Modellbahnen (NEM). According to that standard, H0e represents narrow gauges between , though it is often used to represent gauge railways as well. In strict scale H0e represents a theoretical gauge of , which does not exist as a prototype. But this is very close to the gauge of the gauge railways most widely used in Germany, gauge railways Bosnian gauge most widely used in the former Austro-Hungarian empire, gauge rack railways in Switzerland as well as to the gauge used in parts of the British Empire. Development H0e scale was invented by Egger-Bahn in 1963 - for a long time out of production, but some of the Egger-Bahn line has been reintroduced by MinitrainS. Other manufacturers to produce HOe in recent years have included Roco, Liliput, Bemo and Tillig. United States In 1965 Bob Hayden and Dave Frary stumbled upon an Associated Hobby Manufacturer's AHM "MinitrainS" HOn2½ (now named HOn30) train set at a Woolworth's department store and decided to use it to model Maine 2-foot railroads in HO scale. The AHM MinitrainS line was introduced only a few years after N