Earlier threads here have discussed locomotive grease, how it was "brewed" to custom formulas, and how it is often a lost art. This photo series from The Guardian offers a view into these grease makers.

https://www.theguardian.com/artanddesign/gallery/2022/aug/16/give-grease-a-chance-inside-an-oily-pittsburgh-factory-in-pictures-gordon-parks

Interesting, thanks for posting. Ned

Those are really some superb photographs. Well worth a look, and thanks for posting the link Dr Harrod.