Prepare yourself for a lot of different opinions on this one.
Here is my take.
Regarding minimum radius, 16" is below minimum standards for HO scale. 18" is widely considered to be the bare minimum. 22" to 24" radius works well for short equipment. 26" to 28" radius is better. 30" to 32" is best for a minimum radius. If you want maximum flexibility and the space to pull it off, 34" to 40" radius would be highly desirable.
As far as equipment goes, if you are running steam, every pair of driver wheels requires a broader radius. For example, an 0-4-0 will negotiate 18" radius, but a 4-6-2 really needs 22" to 24" radius to perform well. A 4-8-4 really needs 26" to 28" radius to perform well. A 2-10-2 or 2-10-4 really needs 30" to 32" radius to perform well.
As for diesels, 4-wheel (2 axle) trucks perform well on 18" radius and broader, but a 6-wheel (3 axle) truck diesel really needs 30" radius and broader to perform well.
Just my based upon my own personal experience.
Rich
Alton Junction
Hello Everyone,
Is there any correlation between lenght of rolling stock or locomotive and minimum track radius in HO scale? For example, a 40' hopper car would run well on a minimum 16" track curve or a 72' locomotive would run well on a minimum 22" track curve.