I often get asked about the equivalent KATO unitrack radiuses (radii?) to other manufacturers track. Most often people are interested in PECO Setrack.

All track curves can be thought of as parts of circles. Track radius refers to the distance from the centre of a circle, to the centre line of the track making that circle.

I always advise to plan your layout using computer software such as SCARM or Anyrail, which have libraries of Unitrack pieces so you can experiment with how things fit together.

N gauge

Peco N gauge track is available in four different standard radiuses:

• 1st radius: 230 mm (9 inches)
• 2nd radius: 265 mm (10.375 inches)
• 3rd radius: 300 mm (11.75 inches)
• 4th radius: 330 mm (13 inches)

KATO N gauge Unitrack is based on a system where the standard track spacing is 33mm, so exactly the same radiuses aren't available. However, there are more options. The nearest are as follows:

• 1st Radius: 20-170 R216-45 Curved Track (4 Pcs.) - radius 216mm (beware it might be just too tight for rolling stock that need Radius 1 or larger).
• 2nd Radius: 20-100 R249-45 Curved Track (4 Pcs.) - radius 249mm
• 3rd Radius: 20-110 R282-45 Curved Track (4 Pcs.) - radius 282mm
• 4th radius: 20-120 R315-45 Curved Track (4 Pcs.) - radius 315mm - this is what's included in the standard M1 loop, and often the minimum radius for shinkansen type trains.
• 5th radius: 20-132 R348-45 Curved Track (4 Pcs.) - radius 349mm
• 6th radius: 20-140 R381-30 Curved Track (4 Pcs.) - radius 381mm (30 degree pieces, so you need 4 packs for a full circle)

20-150 R718-15 Curved Track (4 Pcs.) and 20-160 R481-15 Curved Track (4 Pcs.) have larger radiuses but are generally used in sitations where you're using #4 or #6 points and want to get parallel tracks.

20-172 R183-45 curved track (4 pcs), 20-174 R150-45 Curved Track 4pcs and 20-176 R117-45 Curved Track (4pcs) form the 'compact' range of KATO Unitrack. These have very tight radiuses (well below '1st Radius') so are only suitable for the Pocket Line trains, trams and other small locomotives with a short wheelbase. (You can think of them 0th radius, -1th radius and -2th radius if you like!)

OO or HO gauge

Peco (as well as Hornby and other manufacturers) OO/HO gauge track is also available in four different standard radiuses:

• 1st radius: 371mm (15 inches)
• 2nd radius: 438mm (18 inches)
• 3rd radius: 505 mm (21 inches)
• 4th radius: 572 mm (24 inches)

KATO OO/HO gauge Unitrack is based on a system where the standard track spacing is 60mm, so again, exactly the same radiuses aren't available. However, there are more options. The nearest are as follows:

• 1st Radius: 2-280 HO Unitrack (R370-22.5) Curved Track 22.5 Degree 4pcs - radius 370mm (beware it might be just too tight for rolling stock that need Radius 1 or larger)
• 2nd Radius: 2-260 HO Unitrack (R430-22.5) Curved Track 22.5 Degree 4pcs - radius 430 mm
• 3rd Radius: 2-270 HO Curved Track Radius 490mm 22.5 Deg.(4) - radius 490mm
• 4th radius: 2-210 HO Curved Track Radius 550mm 22.5 Deg.(4) - radius 550mm
• 5th radius: 2-220 HO Curved Track Radius 610mm 22.5 Deg.(4)
• 6th radius: 2-230 HO Curved Track Radius 670mm 22.5 Deg.(4)
• 7th radius: 2-240 HO Curved Track Radius 730mm 22.5 Deg.(4)
• 8th radius: 2-250 HO Curved Track Radius 790mm 22.5 Deg.(4)

You'll see that all of these are sold as 22.5 degree segments, so you'll need 16 pieces to make a complete circle.

Any questions? We're unable to help everyone plan a whole layout for free, but we're happy to answer queries or work together to find solutions to your planning problems! Get in touch.