She's a beauty, many thanks for the video. She has a nice elegance to her too, unlike a lot of north American steam locos. I have one 4-8-4. a BLI Southern Pacific GS4. It's a rare one in that it actually works properly! Diecast, smoke unit, sound and very smooth.
[video=youtube;HRF76IzPT-Q]
I don't think she's as pretty as yours though! I think A4Mallard took some close up pics of this, I have none myself.
I have a couple of other freight kettles but I really like the balance of American 4-8-4s.
And yes, that is a Rapido steam generator I believe?