Ok,How do you time a run under steam?
Does the clock start and stop once the loco starts to move,
and then the water level gets to the bottom of the sight glass.
Or,Untill you run the boiler completely out of water?
In my experience at steamups, runs are timed from the moment the loco starts to move, until it runs out of fuel and stops.
I believe this is the generally accepted definition of "run time"..the time the loco is actually under way and moving.
the "warm up" time isnt counted..and most engines are designed to run out of fuel before they run out of water..
this is a good thing!
its not good to run out of water while still having fuel burning, heating a dry boiler.
And --- For engines that can be (for all practical purposes) run indefently such as Coal and Alcohol fired engines, where water can be added while under steam, the run time is measured from when the train gets underway until the operator decides to quit.
More and more gas fired engines also have the capability to keep up steam indefently but when adding fuel the fire must be shut down for safety reasons.