Huge amount of information presented here - at pace, but very well communicated. Always a pleasure to find a channel taking the intelligent approach, rather than the simplistic - two 'naturals' in front of the camera- wisely left to do the talking! Look forward to Pt.2. Thanks for sharing.
In Australia under our Boiler Code mandates that the bottom of the Water Glass must be 10% of the crown to the top of shell above the top of the crown sheet.
There's one thing I was always curious about when it comes to models. For traction engines or other model engines, they're classified by inches like 2" or 6". What exactly do they measure that is 2" or so on for the models?
The scale of the engine is the size comparison compared to the full size engine, i.e. 6" to the foot means it is half the size of the original or 1 in 2. 4" scale is one third or 1 in 3.
As Grahams Engineering said, the scale is x-inches to the foot so 2" is 1/6th scale, 6" is 1/2 etc. For rail however, the scale is given by the wheel gauge. So a 5" loco will have wheels with flanges 5" apart, there's also 3.5" and 7.25" that are quite common (10.25" less so)
