You can create an empty "New Folder" in an assets file
You can drag any file, into that "New Folder", and it will be hidden there, as Trainz can't see it in the "New Folder"
You can copy the whole config file, and paste it into the "New Folder" ... and edit away at the config file in the assets main file
If you ever mess up, and want the original config file back again ... you can drag it back out of the "New Folder" and drop it back in the assets main file
You can also do this with images, reskins, sounds ... etc ...