| TT Scale | |
|---|---|
 TT scale model railroad | |
| Scale | 1⁄10 in (2.54 mm) to 1 ft (305 mm) |
| Scale ratio | 1:120 |
| Standard(s) | NEM, NMRA |
| Model gauge | 12 mm (0.472 in) |
| Prototype gauge | Standard gauge |
TT scale (from "table top") is a model railroading scale at 1:120 scale with a track gauge of 12 mm between the rails. It is placed between HO scale (1:87) and N scale (1:160). Its original purpose, as the name suggests, was to make a train set small enough to assemble and operate on a tabletop.
The scale originated in the USA, but is today widespread mainly in Central Europe, thanks to "Berliner-TT-Bahnen", a defunct East German manufacturer of train sets in TT. It is the second-most popular scale in Central Europe and Russia, after HO, with several manufacturers based in countries such as Germany and the Czech Republic, and was reintroduced to the United Kingdom in 2022. Adherents to the scale maintain it is the smallest practical scale, especially for those who like to build models from scratch.
In wargaming, TT scale equals the 15 mm scale where the height of "standard" 180 cm (5 ft 11 in) soldier height is 15 mm (0.59 in). For British 3 mm TT scale, see 3 mm scale.