Single straight
The HO/OO single is built around the 492 mm Kato HO straight, with a 1 mm overhang at each end so adjoining modules butt cleanly without the rails fouling. Two parallel tracks run at 60 mm centres — wide enough to clear most modern HO rolling-stock without rubbing, and matched to the standard Kato Unitrack double-track spacing.
| Length × depth × height | 490 × 490 × 70 mm | Module box outer dimensions |
|---|---|---|
| Track length | 492 mm | 1 mm overhang at each end |
| Front track setback | 75 mm | From front face of module to first track centreline |
| Track centres | 60 mm | Standard Kato HO double-track spacing |
| Vertical clearance | ≥ 80 mm | Above railhead, scenery and any structure |
| Side clearance, inner curve | ≥ 30 mm | From rail centreline outward |
| Side clearance, outer curve | ≥ 20 mm | From rail centreline outward |
| Track grade | 0% | Strictly level over the whole module |
| Skyboard, visible | 350 mm | Above module deck |
| Skyboard, total | 410 mm | Including the section sitting behind the deck |
| Skyboard stays | 2 × pine 42 × 19 mm | Vertical support battens |
| Levelling range | 70 → 100 mm | Adjustable feet, deck height above table |
Multi-length and corner modules
The HO standard exposes the same family of length variants as the N-scale standard, scaled around the 492 mm Unitrack module. Doubles and triples are exact integer multiples of the single straight; corners use Kato HO #2-210 / #2-220 curve sections at 550 mm and 610 mm radii to give a constant 60 mm track-centre spacing through the bend.
| Single straight | 490 × 490 | Track 492 mm |
|---|---|---|
| Double straight | 982 × 490 | Track 984 mm |
| Triple straight | 1474 × 490 | Track 1476 mm |
| Outside corner | 705 × 705 | No full skyboard |
| Inner curve radius | 550 mm | Kato HO #2-210 |
| Outer curve radius | 610 mm | Kato HO #2-220 |
| Narrow straight | 490 × 350 | Single / double / triple variants |
| Transition | 736 × 490 / 350 mm | Steps between full and narrow depth |
| Max rear extension | 650 mm | Behind rear track centreline |
| Front extension | ≤ 50 mm | Forward of the front face |
| Full-table cross | 1410 mm | Wide cross module |
Electrical and feed ports
HO follows the same wiring discipline as the N standard: a designated feeder track, a fixed wire-hole position, and a strict colour rule for polarity. The mechanical UniJoiner remains identical to the N-scale joiner, so a mixed workshop only needs one box of spares.
| Standard feeder section | Kato #2-151 | 246 mm half-length feeder |
|---|---|---|
| Standard plain section | Kato #2-150 | Half-length plain straight |
| Wire-hole positions | 96 mm and 156 mm | Measured from front face |
| Hole diameter | ⌀ 19 mm | Clearance for plug bodies |
| Polarity convention | BLUE → outer rails | Universal across N, HO and TT |
| Feed cadence (DC) | ≥ 1 / 9 m | At least one feeder per nine metres of track |
| UniJoiner | #24-815 | Shared with N-scale Unitrack |
Unlike the N-scale Unitrack rerailer, the HO version doesn't have rail-top notches that match the T-TRAK 60 mm track-centre spacing. To rerail rolling stock cleanly on a double-track HO module you will need a small 3D-printed jig (in Australia, expect to pay around A$15) sized for the 60 mm centres. Plan for one jig per club rather than one per module.