Nominal size TT

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Model of an E 94 as a Bundesbahn BR 194 in nominal size TT
TT model railroad layout, Christmas 1971
Narrow gauge is also possible: TTm on Piko - N track
BTTB locomotives in size TT

The nominal size TT is a size for model railways standardized in the standards of European model railways (NEM) and the standards of the National Model Railroad Association (NMRA) . The standard gauge with a prototype gauge of 1435 mm has a model gauge of 12 mm and is colloquially referred to as TT gauge. The scale is 1: 120, which is derived from the ten feet to the inch ratio and corresponds to a standard engineering scale in the Anglo-Saxon region.

TT is the abbreviation of the English table top , which means table surface , but basically means: fits on a table . The space requirement of the systems is less than for the nominal size H0 on a scale of 1:87; on the other hand, more details are possible than with the next smaller nominal size N on a scale of 1: 160. TT is therefore also referred to as the center track .


The TT nominal size was developed in the United States in 1946 by Indiana engineer Hal Joyce and sold by HP Products, which he founded in 1945. In Germany it spread through the companies Rokal in the west and Zeuke & Wegwerth in the east. After Rokal went bankrupt in the late 1960s, the nominal size TT was practically extinct in the Federal Republic of Germany. In the GDR and the Comecon states, however, it spread through Zeuke & Wegwerth (which employed over 800 people in Berlin ). After the nationalization in 1972, Zeuke became the VEB Berliner TT-Bahnen (BTTB). After the fall of the Berlin Wall in 1989, BTTB was taken over by the expropriated owner Zeuke and then in bankruptcy in 1993 by the Saxon company Tillig and is still the largest full-range supplier of this size.

Since the turnaround, the market shares in West and East have slowly been converging, which in the case of TT has resulted in a massive decline in market share from 34.2 to 25.5% in the East and an increase from 2.8 to 6.7% in the West alone means between 2004 and 2006. Overall, the share remains practically constant at 7.3% (instead of 7.2). At the same time, the Tillig company is opening up the market in the Czech Republic by holding the annual club meetings both as an event in Germany and in the Czech Republic. In addition, there are also manufacturers of the former Comecon in other countries (e.g. Hungary: Deák, Russia: TT model Russia) for the nominal size TT, which thus contribute to its further spread.

With the appearance of a newly designed coupling - which was presented for the first time at the Nuremberg Toy Fair in 2006 - Tillig was able to replace the previous, less than prototypical yoke coupling from the 1980s with a modern and reliable design based on the NEM shaft .

In the current development, digital technology has also found its way into the nominal size TT. The decoders of the industrial suppliers are mostly equipped with the interface according to NEM 651 (also NEM 652). Recently, there have been new designs with the interfaces PluX ( 12/16/22 ) and NEXT 18, which allow further detailing of the functions.

Great Britain

In Great Britain - analogous to the nominal size 00 there - a different scale and the slightly different designation TT3 have become established. The nominal size is a size for model railways standardized by the British Railway Modeling Standards Bureau (BRMSB) , which is also known under the term 3 mm scale . The scale is 1: 100. 3 mm in the model corresponds to around one foot (304.8 mm) in the original. The designation of the nominal size TT3 continues to be used as a standard in Great Britain instead of the nominal size TT.


For the nominal size TT, the following model gauges are specified in the European Model Railways (NEM) standards on a 1: 120 scale :

track designation Model gauge Prototype gauge Use with prototype gauges
TT Standard gauge 12 , 0 mm 1435 mm from 1250 mm to <1700 mm
TTm Meter gauge 09 , 0 mm 1000 mm from 0850 mm to <1250 mm
TTe Narrow gauge 06.5 mm 0750 mm, 760 mm and 800 mm from 0650 mm to < 0850 mm
TTi (TTf) Field railway 04.5 mm 0500 mm and 600 mm from 0400 mm to < 0650 mm


In Germany, apart from the full-range retailers Tillig and Kuehn, rolling stock is also available from large-scale manufacturers such as Roco , Piko , Brawa and Arnold (Hornby), as well as from numerous small-series manufacturers such as BeckmannTT, Hädl, HERIS , KRES, pmt or Schirmer. After merging with Roco, the high-volume manufacturer Fleischmann stopped its short-term TT engagement or was taken over by Roco. Roco, for its part, announced in autumn 2018 that the TT range would no longer be produced there in the future.

In addition to rolling stock, the Kuehn-Modell company also offers components for digital technology and electronic accessories. The implementation of his own track system makes him the second TT full-range supplier after Tillig.

In addition to Auhagen , Busch and Noch are now also involved in the field of building models . In its range, Auhagen also offers models for this nominal size TT for double use H0 / TT, which are manufactured on a scale of 1: 100. Laser-cut technology is now also finding its way into building models.

TT accessories such as signals, overhead lines, lights, etc. offer companies such as B. Viessmann and Busch. The companies Erbert and Alphamodell offer signals in the TT gauge.


AKTT - Working Group TT-Modellbahn eV
The association was founded in 1977 to maintain (in West Germany) and spread the TT size. He is a consultant in plant engineering and for collectors. The association organizes seminars on all TT-related topics and annually organizes the large TT public fair as a forum for all TT products and as a meeting point for manufacturers and model railroaders. It is important to the association to preserve the family character of this event, because there is hardly any other gauge where manufacturers and model railroaders work so closely together. In addition to manufacturers and system builders, he represents the TT gauge at major trade fairs such as B. in Dortmund, Leipzig and Cologne and publishes the TT-KURIER in Thomas Bradler Verlag as the most important journalistic mouthpiece of the TT size. In addition, he looks after and supports regional groups, round tables and topic groups that deal with TT in many federal states and, if necessary, establishes contact with new members. The association maintains contact with the manufacturers and with the international sister organizations such as TTN, 3mm Society, TT-SIC and the like. a. as well as the TILLIG Club and coordinates activities with them in order to jointly bring the size TT forward.
FKTT - "Friends of TT modules"
It is not an association in the true sense of the word , but a loose association of modular railroaders of size TT. From October 9th to 12th 2013, the first international TT module meeting in Hungary was held at the "Temofeszt". The participants came from six associations from five EU countries. Participants were “FKTT” and “TT-Club Bayern” from Germany ( DR ), “sTTandard” from Poland ( PKP ), “zababov” from the Czech Republic ( CSD ), “Budpesti TT Baratok Klubja” (B.TT .B.) From Hungary ( MAV ) and the Bulgarian Model Railway Club ( BDZ ).
Emerged from the "Stammtisch TT Switzerland / Lake Constance region", which was founded on September 14, 2013 club now an integral part of the Swiss model train scene was. He is committed to spreading the TT gauge in Switzerland through exhibitions, publications and the promotion of young talent and has been very active in the field of exhibitions in Eastern and Central Switzerland in recent years. He also published several articles in the magazines "TT Kurier", "TT Total", " Eisenbahn Amateur " and "TILLIG TT Club aktuell". He works in the design and development of models based on the model of the Swiss railways. Since there were initially only a few models based on the Swiss prototype in the TT gauge (such as the BTTB Eaos freight car ), members of the association began to design models themselves . Manufacturers such as TILLIG or Hädl then use these models for example. Sometimes as special editions in small series (e.g. Agrola or AVIA tank wagons type Zcs). Members of the Fa. on the SBB Re 6/6 and on the SBB Re 460 .
What is special about the club is that it does not have a permanent seat. Since the members live decentralized throughout German-speaking Switzerland , the association meets four to five times a year at different locations and for various exhibitions. The annual summer excursion, which always follows the motto “Railway” and “Switzerland”, is also an integral part of the meeting. The majority of the members of the association come from the former GDR, but also from Switzerland and southern Germany.


  • Andreas M. Räntzsch: The TT-Bahn: History of the model railway on a scale of 1: 120. H - & - L-Publ.-Souvenirs, Schweinfurt 1996. - 84 pp. ISBN 3-928786-55-5 .
  • AKTT & Bradler-Verlag: "TT-Kurier" monthly. published booklet of the "Working Group TT-Modellbahn eV"
  • MBI Media GmbH: "TT-Total" 3–4 times a year published magazine.

Web links

Commons : nominal size TT  - collection of images, videos and audio files

Individual evidence

  2. Figures 2004: Archived copy ( Memento of the original dated June 29, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Figures 2006: Archived copy ( memento of the original from September 11, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / @1@ 2Template: Webachiv / IABot /
  3. ^ British Railway Modeling Standards Bureau (BRMSB), Standard Railway Modeling Dimmensions , accessed September 20, 2017
  4. 3mm Scale Model Railways , accessed September 20, 2017
  5. ^ When TT3 was the next Big Thing. Retrieved September 20, 2017 .
  6. Product range from Auhagen in H0 and TT. (No longer available online.) Archived from the original on October 21, 2009 ; Retrieved April 22, 2010 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /