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Wanted to create a post for reference on what the LGB/Piko R1, R2, R3, R5, R7 values actually translate to in ft/mm AND also bring awareness that what LGB calls R3 and R5 is DIFFERENT than Piko. This is important because MTH lists the minimum diameter curves their engines can take in terms of R2, R3, R5 etc based on the LGB meanings, not Piko. The bottom line is you should always do the actual measurement and rely on the actual ft/mm. Always remember that it is a good idea to run your engines on curves a little wider than that stated absolute minimum rating, regardless of who made the locomotive. This will help ensure you avoid problems such as binding when running. Track Curves - LGB: From LGB's web site https://www.lgb.com/fileadmin/media/lgb/produkte/produktinformationen/LGB_Gleissystem-Info.pdf - LGB website - https://www.lgb.com/products/product-information/overview-of-the-track-system/ Direct link: LGB_Curve_Calculations.pdf R1 = 600 mm (Radius) / 1200 mm (Diameter) R2 = 780 mm (Radius) / 1560 mm (Diameter) R3 = 1195 mm (Radius) / 2390 mm (Diameter) R5 = 2320 mm (Radius) / 4640 mm (Diameter) Translated into imperial: R1 = 23.6 inches (Radius) (1.97 ft) / 47.2" (Diameter) (3.93 ft) R2 = 30.7 inches (Radius) (2.56 ft) / 61.4" (Diameter) (5.12 ft) R3 = 47.05 inches (Radius) (3.92 ft) / 94.1" (Diameter) (7.84 ft) R5 = 91.35 inches (Radius) (7.61 ft) / 182.7" (Diameter) (15.23 ft) Track Curves - Piko: Piko website: https://www.piko-america.com/collections/g-scale-g-track (see R curve & MM values listed on each curve) R1 = 600 mm (Radius) / 1200 mm (Diameter) R2 = ??mm R3 = 920 mm (Radius) / 1840 mm (Diameter) R5 = 1240 mm (Radius) / 2480 mm (Diameter) R7 = 1560 mm (Radius) / 3120 mm (Diameter) Translated into imperial: R1 = 23.6 inches (Radius) (1.97 ft) / 47.2 inches (Diameter) (3.93 ft) R2 = ?? R3 = 36.22 inches (Radius) (3.02 ft) / 72.44 inches (Diameter) (6.04 ft) R5 = 48.82 inches (Radius) (4.07 ft) / 97.64 inches (Diameter) (8.14 ft) R7 = 61.42 inches (Radius) (5.12 ft) / 122.84 inches (Diameter) (10.24 ft)