I think this was brought up before, but I do want to gauge other's interest in dynamic weathering anyway. Since we have systems to make trains wet and also snowy (except for GWE stuff. That is snow-phobic) it should be possible to modify existing tech to allow trains to have varying levels of dirt, smoke-stains, rust, shiny-ness, and other weathering. And since GWE has train washes, those could even be used to remove dirt (but not rust, of course), make trains shiny, and wet too (they don't even make trains wet right now.) Anyway, dynamic weathering is a nice way to increase variety in paint jobs without needing to make tons of different textures for clean, dirty, really dirty, etc. and would also be a good way to combat the usual "I think the trains in this pack are too dirty!" "Oh yeah? Well I think they are too clean and shiny!"
I agree by adding this feature would add a more realistic look as locomotives will get dirty through their journeys. Adding a task within the game where you would be responsible for running the loco's through a train wash to clean them off.
It would be awesome, but because of licencing limitations will not be possible for many locos/wagons. For many licences DTG is only allowed to portrait them in clean and undamaged fashion. Snow and rain may be the only allowed weathering effects. That's also the reason that there is no real crash/derailment simulation. (source: MattPeddlesden's streams)
Well, I don't mind not being able to crash or derail the train to be honest. I wouldn't mind being able to apply a layer of dirt to the entire game though. I understands that train companies want their traction displayed at its best but my view of a railway is one of grit and grime. I've always been dubious to how effective a train wash is.
If companies only want 100% clean stuff, DTG should be in some big trouble now. Have you taken a close look at...any of the locomotives? There is dirt and grime all over TSW, even with paint peeling on YN2 locomotives. That's not 100% clean in my book. Then there's some dirty stuff in TS2018 too-like the extremely dirty versions of the DBS 67 and OBB 2016. DTG would not go out of their way to add those in if it was not allowed. Also, keep in mind that Matt is not the one who does licensing, and not all companies license in the same ways. He might be thinking of some anecdotal time where one company said "that's too dirty" and is using it as excuse to push off mentions of more dirt. The human brain loves to turn an anecdote into all inclusive evidence.
Good grief! Please allow our dear developers to concentrate on truly important essentials rather than distracting them with "realistic" fluff and window dressing.