G Scale Track Geometry

Last Updated: 11 January 2022


Introduction

Each G scale manufacturer typically has its own designation for the different diameters of curved track and switches. As you will see in each detailed list below, the same “R” designation does not always mean the radius is the same across brands. So my suggestion is to look at the actual values within each brand to see how the curves relate to each other.

Careful: don’t mix up radius and diameter, it happens easily. I’ve specified it everywhere, and triple checked it, but before purchasing anything, check a fourth time ;-).


LGB Track Geometry

Official Flyer (PDF)

Geometry Basics (radius in mm, to center)

  • R1 – 600 mm (Curves & Switches)
  • R2 – 780 mm (Curves only)
  • R3 – 1.195 mm (Curves & Switches)
  • R5 – 2.320 mm (Curves & Switches)

Market: Europe & US

PIKO G Track Geometry

Official Flyer (PDF) – Note: outdated as of 2021, the new R3 switches are not yet included in the flyer.

Geometry Basics (radius in mm, to center)

  • R1 – 600 mm (Curves & Switches)
  • R3 – 922 mm (Curves & Switches)
  • R5 – 1.243 mm (Curves & Switches)
  • R7 – 1.565 mm (Curves & Switches)

Market: Europe & US

Train Line Gartenbahnen Track Geometry

Official Flyer (PDF, DE)

Geometry Basics (radius in mm, to center)

  • R2 – 900 mm (Curves & Switches)
  • R3 – 1.200 mm (Curves & Switches)
  • R5 – 2.100 mm (Switches)

Market: Europe (Train Line Gartenbahnen a.k.a. Train Line 45) & US (via TRAINLI)

Thiel Track Geometry

Geometry Basics (radius in mm, to center)

  • 1.175 mm (Switches)
  • 2.000 mm (Switches)
  • 3.000 mm (Switches)

Market: Europe

USA Trains

Geometry basics (diameter!)

  • 4 ft diameter
  • 5 ft diameter
  • 8 ft diameter (Curves & Switches)
  • 10 ft diameter (Curves & Switches)
  • 16 ft diameter
  • 20 ft diameter (?? “#6” Switches ??)

Market: US


Out of Business: Aristo-Craft / Polk’s GeneratioNeXt

Flyer (PDF, DE) – This is a semi-official flyer, distributed (at the time) in the German market via Bachmann Europe a.k.a. Liliput.

Aristo-Craft is already long out of business, but their track is probably still available second-hand, hence I wanted to include it here.

Aristo-Craft track is manufactured to metric dimensions and originally based on LGB dimensions, yet Aristo-Craft has added much more radii.

Important to know: Aristo gave their own “X inch diameter” labels to them, which are not always corresponding to the actual feet/inches value, the metric dimensions are leading in this case.

Geometry basics (radius in mm, to center)

  • 4 ft diameter – 600 mm (Curves & Switches)
  • 5 ft diameter – 750 mm
  • 6,5 ft diameter – 975 mm
  • 8 ft diameter – 1.200 mm
  • 9 ft diameter – 1.350 mm
  • 10 ft diameter – 1.500 mm (Curves & Switches)
  • 11,5 ft diameter – 1.725 mm
  • 12,5 ft diameter – 1.875 mm
  • 14 ft diameter – 2.100 mm
  • 15 ft diameter – 2.250 mm
  • 16,5 ft diameter – 2.475 mm
  • 20 ft diameter – 3.000 mm (Curves & “#6” Switches)

Market: US