This is more of a technical observation than a stylistic one, but I was impressed if they used on-location sound for this. This was before tape recording (perhaps before portable recording technology, in general). If, indeed, the sound was dubbed (e.g. via Foley techniques or similar) then I'm even more impressed, as they had it very well synchronized.
I don't think I would have thought of this in terms of film noir if it hadn't been mentioned that way. I suppose the opening shot of feeding the firebox suggests the inferno, with the engineer and firmen in Vulcan/Pluto roles, and the tra