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 i