My Z Scale layout is very much the result of "trial and error":
much of what has materialized in the end happened to do so
because something else went wrong or didn't work at all -
or because I changed my mind.
Here's a brief account of how it all came together in the end.



Z is the smallest commercially established electric model railway scale with a ratio of 1:220 and a track gauge of a quarter of an inch (6,5mm) - making it only 72% the size of N Scale and a mere 40% of H0 Scale.
Z Scale thus offers the possibility of running trains in a confined amount of space which simply would not be possible in other modelling scales.

For example, the rather complex trackplan shown here only measures 24"x48" (60x120 cm) in Z Scale yet offers continuous running (even twice around) along with several spurs and the potential to model scenic variety.

You might just be able to shoehorn this into that space with N Scale but only by using very tight curves, markedly shorter straights, and foresaking much of the pointwork. And of course it would be absolutely impossible in H0.


Grey River Northern Trackplan (c) David K. Smith

It's almost something of a business card for Z Scale - the small round and round layout, as Z Scale allows for continuous running on a full circle of track with reliable operation of medium and larger locomotives in an area of approximately 20"x20" (50x50 cm); tight curves and short rolling stock will even find sufficient space within the confines of a briefcase.
German toy and train manufacturers Märklin, the inventors of Z Scale, have almost always emphasized the smallness far more than the option to model more in the same given space in comparison to N and HO.

But unless you are into gimmicky micro layouts in odd places, it is in fact precisely this quality of being able to model more in the same given space which makes Z Scale shine.

Z Scale really suits any prototype, but when it comes to the typically long drags and hauls seen on North American rails, the space saving qualities become truly apparent.


A long Norfolk Southern train of covered hoppers rumbles through Downtown Roanoke Va in May 2017

Z Scale is ideal to replicate just that - long trains speeding by or trundling by or awaiting their turn to get back on their way from A to B. You can cut down on the size needed for a layout yet still go for longer trains than the larger scales would commonly allow on anything smaller than tracks taking up the better part of a basement.
  This is because the overall footprint over ties of Z Scale track is only half an inch (12.4 mm) for a single line of straight track.

The width required by a double track line is no wider than a mere 1.4 inches (36 mm), or 1.6 inches (40 mm) when using track with a permanent plastic roadbed base imitating ballast.



The small footprint even of a double track line in Z Scale 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 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 the more varied terrain of East Tennessee, Southwest Virginia and West Virginia.

So my accidental modelling led me in search of something just a little less minute, and that 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 still 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, 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. Rokuhan track is fairly sturdy, but accidental knocking and damaging of protruding track was 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.
Another important decision is the choice of track. In line with the T-TRAK "snap fit" idea of using sectional track I opted for Rokuhan which is a close Z Scale cousin to T-TRAK's standard N Scale Kato Unitrack.
Rokuhan track is modelled on Japanese permanent way, which is closer to the European average of 2,640 ties per mile of track than the up to 3,000 ties on North American track (which Micro Track seeks to replicate).

In 1:220 scale this means 7 ties per inch on Rokuhan track and 10 on Micro-Track - the difference is readily visible, but careful ballasting and weathering of Rokuhan track goes a long way in disguising this.

Rokuhan also offers the most diverse track geometry and has gone beyond the common Z Scale "medium radius" of 195mm and "large radius" of 220mm (and used e.g. by the Australian Z T-TRAK standards) by adding 245mm and 270mm curve radii - which are my choice for corner modules in order to get the best operational and visual results possible.


Arguably the most important modules if you want to have an operational modular layout are the so-called corner segments - they join together to form an oval which allows for trains to be run. Obviously any intermediate modules will expand and enhance the layout, but there's no continuous running without the corners and their curved tracks.

  There is the option of building 180 or 90 degrees segments, but in order to keep the number of module connections to a minimum I settled for one 180 degrees double track and one 180 degrees single track corner module, both falling easily in line with the required ease of building, carrying, setting up and storing.

The corner modules measure 450mm x 650mm, a size which allows the use of Rokuhan's extra-large radius curves plus a standard 110mm straight track attached to both ends of the curve in order to ease the travel of trains into them.

The straight modules have a depth of 250mm which I found to be a good compromise between keeping down overall size and still provide some space for scenic modelling, especially on single track modules (the Australian T-Trak standard for Z is only slightly larger at 280mm).

The most basic setup for this modular layout thus consists of four modular elements: the two corner modules plus two straight modules, providing double track on one end and single track on the other.

Expansion is possible by simply adding additional modules. 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.



All images and graphics are (c) A. T. Wymann unless labelled otherwise

page created 23 April 2012
page updated 2 March 2018