TT scale

TT scale is a model railroading scale, whose name stands for table top.

TT Scale
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TT scale model railroad
Scale110 inch to 1 foot
Scale ratio1:120
Standard(s)NEM, NMRA
Model gauge12 mm (0.472 in)
Prototype gaugeStandard gauge

Its 1:120 scale (from a common engineering scale where one inch equals ten feet) and 12 mm (0.472 in) gauge are roughly halfway between HO scale (1:87) and N scale (1:160). Its original purpose, like the name suggests, was to make a train set small enough to assemble and operate it on a tabletop.

TT retains a comparatively small niche in the United States and in the United Kingdom, but it is the second most popular scale in Central Europe and Russia. Adherents to TT maintain it is the smallest practical scale, especially for those who like to build models from scratch. TT scale was widespread in the Eastern Bloc thanks to "Berliner Bahnen", a manufacturer of the trainsets in TT scale.

In wargaming the TT scale roughly equals the 15 mm scale where the height of "standard" 180 cm (70.87 in) soldier height is 15 mm (0.59 in).


TT scale was invented in the United States by Hal Joyce, a former automotive designer. He founded a company, H. P. Products, in 1945, and the first advertisement appeared in 1946. The product line included locomotive kits, passenger and freight car kits, track and detail parts.

By the early 1950s it had a following, offering less detail than HO—considered by some to be an advantage at the time—and a lower price than most other scales. Numerous other companies began offering TT scale trains, track, and accessories as well, and TT scale became popular in Europe in addition to the United States. In the immediate period afterward, several other manufacturers also began production of TT items, notably the Kemtron Corporation (founded by Levon Kemalyan), which manufactured metal castings in several scales. In Europe Rokal and Zeuke (which became Berliner TT-Bahnen and ultimately Tillig) also began production.

By the early 1960s, TT had been eclipsed in popularity by N scale, which is smaller. H. P. Products discontinued manufacturing their TT line in 1968, and the related tooling and kits have been passed through several hands. In West Germany, Rokal ended production in 1969.

In the DDR, on the other side of the Iron Curtain, production continued. Berliner TT Bahnen, which had superseded Zeuke, widened its offer and exported trains and tracks over most of the Eastern block. As the offer 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 H0. During the 80s trainsets were also exported to the West, offered as simple and cheap entry models to the hobby and earning the DDR well needed hard currency.

With the end of the Cold War, the East German economy was liberalised. Berliner TT Bahnen started to update their offer, but soon ran into financial hardship. The company eventually ended up in the hands Tillig, still today the largest provider of TT equipment. The products were improved, with better technology and more details, to bring them up to date with the offer in other scales.

In the 90s and 00s several other companies started to offer models in TT. Major brands entering TT are for example Piko and Roco, but these decades also saw the emergence of brands such as Kuehn, Beckmann and Kres, which all have set their mark on the scale. Over the last decade interest in the scale has grown, and the offer is now bigger than in Z scale and comes close to rivalling N (at least for European models).

British TTEdit

British TT, TT3 or 3 mm scale
Scale ratio1:101.6
Model gauge12 mm (0.472 in) 13.5 mm (0.531 in) 14.2 mm (0.559 in)[1]
Prototype gaugeStandard gauge

British TT is 3 mm scale; that is, 1:101.6. The "Three Millimetre Society"[1] is a British-based society which caters for railway modellers of 3 mm scale. This society was formed in 1965,[2] eight years after Tri-ang Railways, a British railway manufacturer introduced model locomotives and rolling stock, in what was then a new model railway scale in Britain, known as 'TT' or 'TT3' in 1960. 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.


Currently Tillig is the largest company to make TT scale rolling stock. Most TT scale track sold today is also made by Tillig, which offers both standard model railroad track and an integrated roadbed track using Kato's Unijoiner system. But the growing interest for the scale has led to more manufacturers during the last few years, and the scale has also attracted some of the big actors within other scales. Roco launched their first TT products in 1998, and has a small but growing line. Smaller producers like Kuehn and Beckmann have widened their product lines in recent years, just like Dutch PSK Modelbouw and Czech MTB, which specializes in Czech, Slovak and Polish models.

Russian Peresvet is another manufacturer who produces TT scale models, mostly Russian prototypes. German large scale manufacturer PIKO has also started with a TT line, focusing mainly on German stock, and offer locomotives, wagons and several EMUs. Arnold launched their first new TT models since being bought by Hornby in 2014, and has a small but growing offer.

There is a larger 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 offer of models from Czech, Slovak, Polish, Swiss and Austrian environments. Suppliers of accessories are for example Auhagen, Noch and Viessmann. British Triang produced a Continental/French range but it was only made for a very short while.

The scale is uncommon outside Central Europe, but there are a few manufacturers in other parts of the world. One current producer of British TT is 3 mm Scale Model Railways[3] who supply updated GEM and BEC TT kits as well as a large range of Brass Etch and Resin body kits. American manufacturers include Possum Valley Models (kits), Sleepy Hollow/Gold Coast (ready to run and kits, Costal Engineering (kits) DnS TT Track and others.[4]

List of some TT manufacturers (not complete):

  • Auhagen - landscape material
  • Beckmann - trains
  • Fischer-Modell - trains
  • Gützold - trains
  • Herpa - landscape material
  • IGRA - wagons and buildings
  • Kres - trains
  • Kuehn - trains, track, accessories, digital system
  • MTB - trains
  • Noch - landscape material
  • Peresvet - trains
  • Piko - trains, digital system
  • PMT - trains
  • Polák - landscape material
  • PSK Modellbouw - trains
  • SDV Model - wagon kits
  • Sommerfeldt - catenaries
  • Tillig - trains, track, accessories, digital system
  • Viessmann - accessories, catenaries

Track systemsEdit

There are a handful of track systems available in the scale. Tillig offers two different tracks: with trackbed and without. The latter system is considerably more developed, while the former has a more limited choice but comes with two different kinds of track bed. Kuehn also offers a track system, which is slowly growing, adding more turnouts and other parts as time goes by. The old, u-shaped track of Berliner TT Bahnen is also still available, but usually not advertised.

Czech manufacturer DK-Model also offers a limited range of TTe narrow gauge track, consisting of points and flexible track.


Standards useful to both manufacturers and modellers are maintained by MOROP in Europe. 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.

TT scale locomotives are powered by DC motors which accept a maximum of 12 V DC. In traditional DC control, the speed of the train is determined by the amount of voltage supplied to the rails. The direction of the train is determined by the polarity of the power to the rails. Digital train control systems have, just as in other scale, become more and more common. The most popular digital control systems used in TT scale model railways is NMRA-DCC, most commonly using systems from Roco, Uhlenbrock, Kuehn, Piko or Tillig.

There are several coupling systems used in TT. Rokal and Zeuke had simple hook-and-ring systems for their model, but these are hardly in use anymore. Berliner TT Bahnen introduced a modernized coupling in the 70s, and this is still today the standard coupling on models from some manufacturers. The most common coupling today, however, is the Tillig close coupling system, and most ready-to-run models are equipped with this. There are also different systems for magnetic couplings, permanent couplings and so on, and some modellers also use Kadee-style couplings.

Practically all TT scale rolling stock made today is equipped with coupling pockets according to the standard NEM358. This means all modern models have interchangeable couplings.

Related scalesEdit

Variations include TTn3, where TT scale is run on N gauge (9 mm / 0.354 in) track for narrow gauge operation. In New Zealand, this is known as NZ120[5] and is growing in popularity as a means of modelling the nation's 3 ft 6 in (1,067 mm) gauge railway network. TT9 is modelling using British TT scale on 9 mm track to model 3 ft (914 mm) gauge lines.

TTe uses 1:120 scale on Z gauge (6.5 mm / 0.256 in) track to represent narrow gauges around 750 millimetres (2.5 ft).

Several scales also use TT gauge but with a larger scale to represent narrow gauge railways. The most common are HOn3½ gauge (which represents 1067mm gauge in 1/87 HO scale and H0m gauge representing metre gauge track also for 1/87 HO scale.

See alsoEdit


  1. ^ a b "The 3mm Society". Retrieved 2020-09-18.
  2. ^ "Over 50 Years of 3mm Modelling". The 3mm Society. 1997. Retrieved 2020-09-18.
  3. ^ 3mm Scale Model Railways.
  4. ^[dead link]
  5. ^ New Zealand Rail 120.

External linksEdit