G scale Sectional Track Note, the numbers below are APPROXIMATE, not exact, there is variation between manufacturers. Check the exact numbers on the manufacturer's site. Pick your R number "R" number LGB diameter feet Piko diameter feet Train-Li diameter feet Train Line 45 diameter feet LGB radius feet Piko radius feet Train-Li radius feet Train Line 45 radius feet R1 4' 4' 2' 2' R2 5' 6' 2-1/2' 3' R3 8' 6' 6' 8' 4' 3' 3' 4' R4 ~11-1/2' 8' 5-3/4' 4' R5 15' 8' 7-1/2' 4' R6 R7 10-1/4' 5'+ Pick your diameter/radius Diameter Feet Radius Feet LGBR Number Piko radius feet Train-Li diameter feet Train Line 45 diameter feet Aristo Craft USA Trains 4 2 R1 R1 4' 4' 5 2-1/2 R2 R2 5' 5' 6 3 R3 R3 R3 6-1/2 ~3-1/4 6.5' 8 4 R3 R5 R4 8' 8' 9 4-1/2 9' 10 5 10' 10' 10-1/4 ~5 R7 11-1/2 ~5-1/2 R4 11.5' 12-1/2 6-1/4 12.5' 14 7 14' 15 7-1/2 R5 15' 16 8 16' 16.5 ~8-1/4 16.5' 20 10 20' 20' Link to Piko track planning guide: https://cdn.shopify.com/s/files/1/1960/4221/files/99350_G-Track_Flyer.pdf?9757276037842777937 Link to LGB: Notes: There is no R4 curved track from LGB There is no even numbered curved tracks from Piko What a mess huh?