Here is the answer that I got from Google AI.
Yes, the Union Pacific Steam Team keeps the fire lit or "banked" in the Big Boy No. 4014 overnight when it is on tour. [
1,
2]
- Banked Fire: The crew keeps a slow, low-intensity fire burning in the firebox overnight. This ensures the boiler stays warm, reducing the time needed to raise steam the next morning and preventing structural stress on the boiler caused by rapid heating/cooling cycles.
- Oil-Fired System: Since its restoration, the 4014 is an oil-burner, which makes managing the overnight fire easier than the original coal-firing method. The oil burner is tuned to a low setting to keep the engine "alive".
- Overnight Watch: The locomotive is not left unattended. A "watchman" or member of the Steam Team oversees the locomotive to ensure water levels are maintained in the boiler and the fire remains safe.
- Boiler Car "Howard Fogg": As part of the support crew, the boiler car Howard Fogg is often used during tours to provide steam and keep the 4014 hot when it is not operating. [1, 2, 3, 4, 5, 6, 7, 8]
If the engine were to go completely cold, it would take a significant amount of time and care to bring it back to operating temperature (up to a full day).
Here's a shot of the "Howard Fogg" boiler car that is referenced, that I took. Just a partial since I was standing too close to the track.
View attachment 264721
Howard Fogg is one of my real regrets.
Mom was a professional artist--a painter--and she sold some 2,500 compositions over the course of her career. She also knew Howard Fogg*, and at one point she managed to wrangle from him an opportunity for me to tour his studio, and even have some of his time just for me, then a mere aspiring artist (I draw, but was never a painter). I was seriously depressed at the time by the impending demise of the D&RGW, so much so that I had to just walk away from the hobby completely few years later.
Which I did, not long after the D&RGW bought the SP. I was as surprised as anyone at that one, and for a short time found some enthusiasm again, but when it became clear the black and aspen gold would be phased out completely it really was the last straw for me. So I just quit the whole thing.
To my great regret, I did NOT take Howard up on his offer. Dearly wish I had. A real opportunity declined by a fool, that one. What was I thinking?
It was my nephew, then six, and his growing enthusiasm for model trains who got me back into this thing, starting around 2006 when I took him to his first Rocky Mountain Train Show in Denver. That was the beginning of HIS collection, and I dug out my own and gave it to him not long after. We built it up over the years, though his own interest waned a bit after we started building a small layout for him. But I figured it would come back once he got older, and still do believe it will once he gets through medical school, residency and sets down roots somewhere--probably the east coast, unless things change. Or the west coast if his girlfriend gets her way. All good.
In the meantime, I'm curator of what little is left after the burglaries, so I'll move on ahead at whatever pace life allows. And if I can just get a reliable tow vehicle I'll invest in a trailer...and start doing the traveling Free-moN trainshow stuff. Or at least try to. Start small, with no trailer (and even though I have to pull other utility trailers regularly just to maintain this place...and the other), but maybe it'll grow into something larger. We'll see.
[* Fogg was one of the best known railroad artists in the US, for those who might not know]