Comparison
Rail codes compared
A rail’s “code” is its height in thousandths of an inch: code 100 rail is 0.100 inch tall, code 83 is 0.083 inch. A lower code means a lower, finer-looking rail. Here’s what each code works out to — and the full-size rail it represents.
| Code | Height (mm) | Height (inch) | Full-size equivalent | Height drawn to scale |
|---|---|---|---|---|
| Code 100 | 2.54 | 0.100 | 221 mm | |
| Code 83 | 2.11 | 0.083 | 183 mm | |
| Code 75 | 1.91 | 0.075 | 166 mm | |
| Code 70 | 1.78 | 0.070 | 155 mm | |
| Code 55 | 1.4 | 0.055 | 122 mm |
Which HO track uses which code
| Track | Rail | Source |
|---|---|---|
| Peco Streamline OO/HO (incl. SL-103 flexible track) | Code 100 | Peco: SL-103 Streamline code 100 |
| Peco Setrack OO/HO | Code 100 | Peco: ST-220 Setrack curve |
| Peco Streamline OO/HO “finescale” | Code 75 | Peco: Streamline range |
| Peco Streamline HO (North American style) | Code 83 | Peco: Streamline range |
| Atlas HO track | Code 100 and code 83 | Atlas shop |
| Trix C-track (2-rail) | 2.1 mm rail — the same as code 83 | Trix: C-track characteristics |
| RocoLine | 2.1 mm rail profile | Roco: track pages |
Peco sells transition track to join code 75 to code 100 and code 83 to code 100 (Peco: Streamline range). Checked 18 October 2026.
Reading the table
- Height is code ÷ 1000 inches, × 25.4 to get millimetres.
- Full-size equivalent is the model height × the scale ratio — so you can compare it with the rail on the railway you model.
- Before mixing codes or buying finer rail, check what your track maker and your rolling stock makers say about joining and running on it.
Which track systems use which codes? See our track & layout guides.
Where the numbers come from
The definition of rail code and the scale ratios come from these sources. Checked 18 October 2026.