config is in every asset used in Trainz. In content manager find the asset and right click "edit in explorer". You will find a notepad file named config. Open it up and edit out the tag. Then save, close and click "commit" in TS12 or "submit edits" in TS19.
It shows up in railyard but does not load at all. CM 3.7 says it has incorrect textures or something? whatever the case it shows up red (Faulty in CM 3.7) in surveyor.
N3V doesnt want you to use some assets like certain speedtree groups as they are really bad on performance but there already in game so they display but you cant use them. As for other assets (like the CB&Q SW7) especially in earlier titles I think they were either Easter eggs or used in special sessions for those titles. Or unused content left in the game. Remember in TS04 and TS06 there were scenarios, I think that's where they were used.
