H0 scale (HO)

H0 (“half zero”, 1:87, gauge 16.5 mm) is by far the most popular model railway scale — with a correspondingly huge choice of vehicles, track systems and accessories. It offers the best balance of detail and manageable size, but needs room: even a simple R1 oval (about 360 mm radius) occupies a good 1.5 × 1 m. Common track systems: Märklin C (three-rail), Piko A, Roco geoLine, Fleischmann Profi, Tillig Elite.