OO GAUGE · REFERENCE
Hornby setrack reference chart
Part numbers and measurements for the Hornby OO setrack pieces used in the First Radius planner, and how they are designed to fit together.
Straights
| Part | Name | Length |
|---|---|---|
| R610 | Short straight | 38mm |
| R600 | Standard straight | 168mm |
| R601 | Double straight | 335mm |
| R603 | Long straight | 670mm |
Curves
Setrack curves come in four radii, each in a standard 22.5° piece and a 45° double piece. The diameter is measured across the middle of the track; add 29mm for the width of the track itself.
| Part | Name | Radius | Angle | For a circle | Circle diameter |
|---|---|---|---|---|---|
| R604 | 1st radius curve | 371mm | 22.5° | 16 pieces | 742mm |
| R605 | 1st radius double curve | 371mm | 45° | 8 pieces | 742mm |
| R606 | 2nd radius curve | 438mm | 22.5° | 16 pieces | 876mm |
| R607 | 2nd radius double curve | 438mm | 45° | 8 pieces | 876mm |
| R643 * | 2nd radius half curve | 438mm | 11.25° | 32 pieces | 876mm |
| R608 | 3rd radius curve | 505mm | 22.5° | 16 pieces | 1010mm |
| R609 | 3rd radius double curve | 505mm | 45° | 8 pieces | 1010mm |
| R8261 * | 4th radius curve | 572mm | 22.5° | 16 pieces | 1144mm |
| R8262 * | 4th radius double curve | 572mm | 45° | 8 pieces | 1144mm |
Points
| Part | Name | Straight road | Branch |
|---|---|---|---|
| R8072 | Left-hand point | 168mm | 22.5° at 438mm radius |
| R8073 | Right-hand point | 168mm | 22.5° at 438mm radius |
How the pieces fit together
- Each radius is 67mm wider than the one before. That is Hornby's standard spacing between parallel tracks, so a 1st radius loop sits neatly inside a 2nd radius loop as double track.
- A point is the same length as a standard straight. Its straight road is 168mm, and its branch is a 22.5° curve at 2nd radius, so a point can replace a straight in an oval without upsetting anything else.
- Two points make a crossover. Each branch steps the track sideways by 33mm, so two points of the same hand joined by their branches link two parallel tracks exactly 67mm apart. See the points guide.
* We are still double-checking the 2nd radius half curve and the 4th radius pieces against Hornby's own figures. All measurements come from Hornby's published product details.