Realistically, when a train is used for an extended period of time (I’m talking in years) it starts to get a lot dirtier and messy than when it was delivered. This is due to the train picking up a lot of grime and mud from the ground, and when the train passes at high speeds on a rainy day, you can see it starts to spray wet dirt around, that gets stuck onto the trucks, fuel tank, and other underbody (as well as upper body) components. This gives it the “weathered” look, as how railfanners call the process. I would like a feature that lets us have the same realistic effect on trains in TSW. This can be toggled on or off in the settings menu for those who like to keep their trains brand new. It would make a nice feature in TSW 2021 or future versions of the game to make it more realistic. Another thing, as you can see in TSW, when a train starts to emit large amounts of exhaust (when a train revs up to high throttle in TSW you can see the cloud of exhaust), it tends to gather up around the exhaust stack and around the engine doors. A feature like this would be great for TSW and would make the trains look more weathered out, as you can see on top of real locomotives there is a black spot on the exhaust silencer. Of course, everything can be toggled on or off in the menu.