... problems- they will go round almost any radius unless very long wheelbase. You might have problems with couplings and buffer-locking. Generally it is 6-coupled or 8-coupled steam locomotives which create the limiting condition. For the shortest turnout with the largest radius, you could: 1. set a generic type V-crossing (or curviform, but not for crossovers). 2. use a short curved switch. For example, these are both above 30" radius using the GWR range of curved switches: 2_311944_200000000.png Although the one with a 10ft switch is a fraction longer and smaller radius, I think I would prefer it for the easier deflection angle of the longer 10ft switch. But neither of them are going to look very good in a running line. Short 1:5 turnouts are normally found only in yards and sidings. How much space do you have for something longer? If you have several turnouts in succession can you merge two of them into a tandem? Running line turnouts are not usually shorter than about 1: ...