Thanks for the video(s), i have a fascination with steam locomotives, and this entire series is absolutely fantastic.

hmm this don't look that old, like 70's or 80s maybe, the introspection and display of tools is a bit different then how we did things in the states, the flue welder I believe was different here and completely automatic but used induction heating I believe in the latter years of steam in the usa, and stays here are also welded but they also cut off the ends and hammer over the ends to lock them in place caulk them tight and then welded to thermally bond it to the sheets and the stay itself. and we also safe end our tubes and reuse them if possible up to 6 times after each need of occasional regulated inspection for us its 15 years or 1472 operating days, if I had to guess though this was in east Germany the footage being shown or maybe Poland, but they are very detailed about the parts and processes in the documentary superb even talks about sanding the flues to clean them, you will often hear about sanding the flues but they don't tell you why.

how much steam boiler capacity required for steam locomotive