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.

In Europe, Rokal and Zeuke (which became Berliner-TT-Bahnen and ultimately Tillig) began production in West and East Germany respectively towards the end of the 1950s.

In West Germany, Rokal was sold to competitor Wesa (which marketed their own 13 mm-track, 1:100 scale), and production ended in 1969.

As the range became more and more comprehensive, offering not only trains and tracks but also accessories such as signals, lights and working catenaries, it became a serious contender to HO.

During the 1980s, train sets were also exported to the West, offered as simple and cheap entry-models to the hobby and earning East Germany much-needed hard currency.

There is also a number of Russian manufacturers such as Peresvet (Пересвет) and TT-Model (ТТ-Модель) which produce TT scale locomotives and wagons of various prototypes in many liveries and schemes.

With the emergence of 3D modeling software and 3D printing, many modelists in Russia have started to produce a vast variety of rolling stock and locomotives of their own in TT scale.

The reason for the slightly larger scale was that the available motors in the 1950s were too large to fit in the British loading gauge.

The simple solution was, just like in choosing OO over HO and as later would happen in N gauge, to make the trains slightly larger but keeping the track at international scale.

The aims of the society are to encourage modellers working in this scale, and it produces a quarterly magazine and assists with the production of locomotive and rolling stock kits, components and the supply of secondhand items and spares.

TT was reduced to a niche scale in Britain with the fall of Tri-ang, and remained so for a long time.

The company launched its new TT:120 scale 12 mm gauge code 55 track and UK prototype accessories.

[4][5] Writing in the Peco Publications & Publicity magazine, Railway Modeller, editor Craig Tiley stated, To explain: rather than perpetuating the hybrid combination of 3 mm:1 ft scale and 12 mm gauge track that was adopted by Tri-ang for its TT range during the 1950s and '60s, Peco has instead chosen the accurate scale and gauge combination of 2.54 mm:1 ft on 12 mm track.

In 2022 Hornby also announced their new TT programme with British trains, offering a wide range of locomotives, carriages and accessories, reintroducing the scale in Britain.

There is greater variety in the accessories market, where some companies have a long-time involvement with the scale and others recently started to support it as well.

Prototypes are mainly German and Central European, with a wide offering of models from Czech, Slovak, Polish, Swiss and Austrian environments.

Moreover, the British manufacturer PECO introduced Streamline Flexible Track and Medium Radius Turn-Outs with code 55 rail in June 2022.

These standards are generally the same for such elements as track gauge, scale ratio, couplings, and electrical power, and differ for clearances and other factors that are specific to the prototype being modelled.

In Japan TTm is also used to represent 3 ft 6 in (1,067 mm) gauge railways under the name "TT-9", and has had limited commercial support from manufacturers such as Tenshodo.