Almost every Irish modeller's first decision is which scale to start with — and almost always the choice is between OO (1:76, 16.5mm gauge) and N (1:148, 9mm gauge). For Irish-outline modelling specifically, the answer is more clearly OO than it is in the broader UK market. Here's why.
The Numbers
| OO | N | |
|---|---|---|
| Scale ratio | 1:76 | 1:148 |
| Gauge (track width) | 16.5 mm | 9 mm |
| Typical loco length | ~200 mm | ~100 mm |
| Min space for an oval | 8' × 4' (or 6' × 4' tight) | 4' × 2' |
| Cost per loco | €180–€350 | €120–€280 |
| Detail visible | Excellent | Good |
| Reliability of mechanisms | Excellent | Very good (modern); poor (older) |
The Irish-Outline Reality
Irish Railway Models (Accurascale) produces almost exclusively in OO gauge. The previous-generation manufacturer Murphy Models was also OO-focused. If you go N, your Irish-outline RTR options are dramatically smaller — you'll be reliant on conversions from British N-gauge models, kit-builds, or imports.
This is the single biggest factor for most Irish-outline modellers. If you want to model Irish prototypes specifically, OO is essentially the only sensible choice.
When N Makes Sense for Irish Modellers
- You have very limited space. A spare-room corner, a top-of-wardrobe shelf, a 4' × 2' under-bed plank — N gives you a credible layout in space OO can't fit.
- You want long trains for visual scale. A 12-coach passenger train is 2.4m in OO; in N it's 1.2m and easily fits a typical layout.
- You're modelling broader landscapes. N's smaller scale means your scenery dominates and your trains feel like part of a larger world.
- You're not married to Irish-outline RTR. If you're happy modelling generic British or European prototypes, N's range is excellent.
When OO Makes Sense (the default for most Irish modellers)
- You want Irish-outline RTR. This is the deciding factor for most.
- You have a typical spare-room space (8' × 8' or larger). OO fits comfortably.
- You value detail and weight. OO models feel more substantial in the hand — they have better motor reliability, easier maintenance, more visible detail.
- You want to easily mix and match British and Irish prototypes. OO is the standard British scale; ranges are vast.
- You'd benefit from club support. Irish clubs are mostly OO-focused. You'll find more help.
"I started in N because I had a small box room. Two years later I built a shed for the OO layout I really wanted. If you can fit OO, fit OO."
— common refrain at any club open meeting
What About HO?
HO (1:87, 16.5mm gauge — same track as OO) is the standard continental European and US scale. For Irish-outline modelling, HO is even thinner than N — almost nothing in Irish RTR. Skip HO unless you have a specific European-prototype project in mind.
What About Narrow Gauge (OO9)?
OO9 (1:76 scale on 9mm narrow-gauge track) is a niche but charming option for modelling Ireland's narrow-gauge railways — West Clare, Cavan & Leitrim, Tralee & Dingle, Bord na Móna. Mostly kit-built or scratch-built rather than RTR. Excellent space-efficiency. Best as a second project once you've finished a starter OO layout.
The Recommendation
Start in OO unless you have a specific reason not to. The Irish-outline range, the club support, the resale value, and the ergonomics all favour OO for new Irish modellers. N is a perfectly valid choice for tight spaces — but most Irish modellers who start in N for space reasons end up adding OO later anyway.
Ready to buy?
Once you've picked your scale, our retailer directory has the best Irish and UK options.
Where to Buy