Brilliant detail. Love it.
Remember roundhouses and the like are/were smoky, dirty places. The older they are, more dirtier. Oil, coal dust, ash etc. got everywhere. Timber framework was almost black in several places. The excellent looking platform would have people up and down it over the years. Dirty boots and greasy hands leave their mark.
The comments are definitely not a criticism, just observation of a locomotive shed near where I live. A little extra to the ordinary makes a scene extraordinary.
Keep up the excellent work.
David