Common questions, answered briefly

At the joining faces of a module — yes. The standard is built around the geometry of the Kato Unijoiner, which is what physically and electrically bridges one module to the next. Without Unitrack at the edges, your module simply will not connect to anyone else's.

Inside the body of a longer module, however, flex track is permitted. Peco and Atlas Code 80 are the recommended brands. If you go this route, you must adapt back to Unitrack at each end using a Kato #20-045 conversion piece. Peco flex needs roughly 3 mm of cork underlay to bring the railhead up to Unitrack height. Atlas Code 55 is too low and is not compatible — Unijoiners will not bridge the height difference cleanly.

Yes, but only at specific lengths. The total module length must equal a multiple of the standard single-module track length, minus the 2 mm Unijoiner gap. For N-scale that gives you 308 mm, 618 mm, 928 mm or 1238 mm. HO/OO modules step in 490 mm / 982 mm / 1474 mm. TT scale uses 413 mm and 828 mm. Mini-T uses multiples of 62 mm.

Anything in between will not join — a stack of modules at a meet relies on the cumulative track length being an exact multiple of 310 mm (in N) so that Unitrack pieces in adjacent modules line up. Build to one of the listed sizes or your module sits out the running.

To leave room for an actual scene. 300 mm gives you a usable foreground, mid-ground and a backdrop with real depth — meaningful scenery rather than a strip of grass. The extra depth is what makes Australian T-TRAK modules read as small dioramas in their own right.

The track geometry is identical to the international form. A 300 mm Australian module will join a 210 mm international module without any issue — the only difference is the depth of scenery behind the rear track. From the front, both modules look the same; from above, the Australian one simply has more landscape behind the trains.

Either, or both. The track standard and the connector convention are deliberately power-supply-agnostic — Kato feeders carry whatever you put on them. The most common arrangement at a meet is DCC on the rear (back) main and DC on the front main, so two operators can run side by side without conflict.

Whatever the choice, the front and rear circuits must remain electrically isolated from one another, regardless of which one is DCC and which is DC. The standard does not prescribe a particular DCC command station or booster — that is up to the host of each meet.

Every Kato feeder cable carries one blue and one white conductor. The convention is straightforward: the blue wire connects to the rail furthest from the layout's centreline. On the front main that means the front rail; on the rear main that means the back rail. The white wire goes to the inner rails — the two that run closest to one another.

If every modeller wires their module the same way, every module joins to the next without any polarity surprises. It is a simple rule that prevents the worst single category of fault on the day of a meet — a short the moment the bus is energised.

Yes — and many Australian modellers do. Use blue and white PowerPole housings to mirror the Kato wire colours, so the polarity convention carries through end to end. PowerPoles are robust, sexless, and easy to crimp or solder.

The only thing you need at a meet is a short PowerPole-to-RCA adaptor cable, so your home wiring interfaces cleanly with the standard Australian RCA bus convention. Let the meet coordinator know in advance that you are running PowerPole — they may ask you to bring an extra adaptor or two for the spare-parts box.

The baseline is a railhead height of 70 mm above the underlying table, with the levelling feet able to extend that to 100 mm. The fittings are M6 carriage bolts running in M6 tee-nuts at each of the four corners.

That 30 mm range is enough to take up any sag, twist or warp in a typical exhibition trestle — and it is what allows a long string of modules from different builders to settle into a continuous, level mainline without anyone shimming with packing.

A smaller-footprint variant of the N-scale standard. Mini-T modules are 150 mm wide, with track lengths in multiples of 62 mm and a 33 mm alternate track spacing. The rules on materials are stricter than the main standard: 12 mm hardwood ply only, because pine and MDF warp at the smaller dimensions.

The Australian Mini-T variant sits at 70 mm tall — the same railhead height as the main N-scale standard — so Mini-T modules can join into a regular N layout. The Japanese version of Mini-T is shorter, which is a quiet incompatibility to be aware of when sourcing reference designs from overseas.

Yes. Chapters H2 through H16 of the Australian guidelines cover HO and OO. The N and HO/OO chapters share the same introduction, electrical, control and meets material — the geometry chapters are the only ones that fork by scale.

HO/OO modules are 490 × 490 × 70 mm, with track centres of 60 mm and a front setback of 75 mm from the module front face to the front edge of the front track's ballast. Lengths step in 490 mm increments, exactly as N-scale steps in 308 mm.

Don't pull them apart by hand. Lifting one module straight up off another bends Unijoiners — and a bent Unijoiner will short, lose contact, or tear the next time you try to use it. Damaged Unijoiners are the single most common preventable failure at a meet.

The right technique is to slide a 300 mm steel ruler down between the two module ends, then twist it gently sideways. The modules spring apart cleanly with the joiners undisturbed. A long blunt knife or a thin offcut of timber works similarly, but a steel ruler is the standard tool.

Three things, and only three. First, respect the clearance gauges — 45 mm vertical and 12 mm per side for N-scale, 80 mm vertical and 30 mm outside / 20 mm inside for HO/OO. Second, keep loose scatter materials back from the joining edges; a stray lump of ballast wedged at the end of a module is enough to derail a long train. Third, write your name on the back of the skyboard so your module gets back to you at the end of the day.

Beyond those three, the era, country, prototype, level of detail and stylistic choices are entirely yours.

No. The Australian guidelines say nothing about era or country of prototype — and that is deliberate. A typical meet will see Australian outback diesels, Japanese Shinkansen, North American Class I freight and English branchline tank engines circulating on the same loop within the same hour.

What matters is the module geometry: the track, the heights, the electrical convention, the clearances. Get those right and your module joins the others. The trains running on top can be from any continent and any decade.

For exhibition use, yes. The convention is 200 mm visible above the box on N-scale modules, and 350 mm on HO/OO. Make the skyboard removable so the module still fits its transport tub for travel — most exhibition tubs are sized to the box dimension, not the box plus skyboard.

Paint the skyboard light blue. Keep the top corners square or rounded to a radius no greater than 18 mm. Corner modules typically don't carry a full skyboard — fill the gap with a hill, a forest, a tall building, or whatever scenic element bridges the visual line between the two flanking modules.

No. All mainline track must be level — a 0% grade — through the full length of the module. The Unitrack-to-Unitrack join at each module edge has to be flat and at the standard rail-top height, otherwise the joint shorts, derails, or simply stops a train cold.

You can run a hump or a small change of level wholly within a module if you bring the track back down to standard height before reaching the joining face — but in practice almost no one does this in N or HO/OO. T-TRAK is a level-running format. If you want grades, build a permanent layout.

The Australian T-TRAK community runs a groups.io mailing list — that is where new meets are announced, Module Information Forms are circulated, and most builder-to-builder Q&A happens. Most state-level model railway clubs also include T-TRAK builders, and a club night is often the easiest way to meet someone who can show you a finished module in the timber.

Major Australian model railway exhibitions usually have a row of T-TRAK modules running on one of the demonstration tables. Walk up, ask questions — Australian T-TRAK modellers are uniformly happy to talk about it.