The small footprint even of a double track line in Z Scale - which has an overall width of no more than 40mm / 1.6 inches - lends itself perfectly to a modular approach - just the ticket for someone wanting a layout which is not permanently on display but easy to set up and dismantle again in a sensible amount of time.
I initially went for a true minimum space formula with a width of just 6 inches (15 cm) for a double track line.

This still left some room for a scenic shoulder on both sides along the permanent way, but while this was okay for a flat Central Florida scenery, it proved too narrow for modules trying to replicate more varied terrain further North on the East Coast.

My accidental modelling thus led me in search of something just a little less minute, which is how I came across T-TRAK - a tabletop (hence the "T") modular system with individual modules which are a lot smaller than those of other systems.

(c) Unofficial T-Trak Handbook

(c) Australian T-TrakGroup

  Originally developed by N Scale modellers in Japan, the T-TRAK concept relies on the interlocking qualities of Kato Unitrack, which is the required brand of track (at least at the joining ends of a module). With the obvious similarity between Kato's N Scale and Rokuhan's Z Scale track (both have a moulded ballast base and a similar locking mechanism to join individual track pieces) the concept as a whole seemed interesting.

The Australian T-Trak Group has metric dimensions for Z Scale, and even though these are based on Micro-Trains track they are fully compatible with Rokuhan track. The depth of a standard module is set at 280mm with a width of 328mm; the track overhang on both module ends is a typical feature of T-TRAK which is supposed to ensure good interlocking (with e.g. Kato Unitrack) even between modules which aren't quite square (and therefore wouldn't fit well). The resulting small gap between modules is a defining trait of T-TRAK modules, but not everybody's cup of tea.

The modules are easy to build and comparatively easy to store, transport and set up. The "snap together" formula allows to put together layouts ranging from a simple circle to large complex layouts.

Developed for (and still overwhelmingly used for) N Scale, the idea has also been adapted for HO and Z Scale (recently incorporating the larger radii curves offered by Rokuhan by T-TRAK-Z), but given that I simply intended to have a modular layout which could be set up temporarily without much of a fuss I did not have to concern myself with the compatibility of parts of my layout with other modeller's modules - which is why I took the T-TRAK concept as a basis but introduced some changes according to my own preferences.

The most important change concerns the "interlocking" between two modules. I decided to use Rokuhan track for this modular layout; a close Z Scale cousin to T-TRAK's standard N Scale Kato Unitrack, it is fairly sturdy, but accidental knocking and damaging of protruding track was still a major concern.

The solution was to use the shortest piece of Rokuhan track - which measures 25mm - as a temporarily inserted "bridge" between two modules, thus setting back the tracks about 1,25cm from the edge of each module.

This change to the concept actually renders my modular segments incompatible with true T-TRAK modules but also helps to iron out the inevitable slight discrepancies to be found between individual DIY modules.



The modules essentially assemble into an extended oval layout, designed for continuous single line running with a double track passing loop at one end, measuring 65cm (25.6 inches) in width across the corner modules.

Expansion is possible by simply adding additional intermediate modules (only two of which are pictured here for the sake of clarity). The basic layout can also be shrunk to a basic oval by using just the two corner modules, although this renders the inner line of the double track segment non-functional.

  An important aspect of the modular segments is a strict adherence to level track, resulting in no inclines of the track itself while the scenery around it may rise and fall in all directions. Overall, this not only results in smoother operation but also makes connecting modules a lot easier.



page created 6 January 2016
last updated 6 December 2019