Re: 493 Video

Will is correct.

The problem that steam locomotives face ultimately comes down to a large disparity in temperature from the firebox to the boiler, one way or another - be it:

- sucking cold air through the firebox when the locomotive is working hard
- running low enough on water to expose the crown sheet to the steam space with a raging fire

etc. There's probably several more examples, but the issues come when you can't keep the temperature consistent. For a static test fire, where you can't even get the draft anywhere near working hard on the road - you aren't going to be boiling off THAT much water or making that much of a problem.

The fire brick acts more like a capacitor, holding in heat for a while and slowly giving it off. It wouldn't cause an issue after time even if the water level dropped just due to the nature of conductive heat transfer.

Mark Huber
Hyce on YouTube