Golden Rule

[TinGoat]

With Harold's discovery of 5.5mm / 55n3 I was reminded of the following information:

I'm passing this along from Brian Fayle who has it from Steve Bennett, a well known Brit modeller, who got it from some guru. It works:

The Golden Rule for a Loading Gauge is:

WIDTH 3.25 times track gauge

HEIGHT 5.25 times track gauge