I'm looking for some kind of tutorial on how to open script files (which are apparently mostly in OUT format) for rolling stock. Is that even doable and are we allowed to modify scripts? How can I even open them?
Most developers encrypt them, as it is their intellectual property they want to protect, so others don't steal it for their creations. For more info, Google and Youtube are more helpful than this forum.
I've not said it would. But how can the developer be sure everyone is as honest as you? So it's locked, as next to the models, it's the most precious work.
I guarantee 100% that it is possible, you are allowed to change them, after all it is just a game and you are not going to hack NASA. If you have programming knowledge, with the help of hooking and detouring methods you can flash the lua codes back to the source code again.
Hacking/reverse engineering is of course possible, you can do that with anything if you have the required knowledge and resources, what we are talking about as you damned well know is .out files are not editable on a normal user level and being "allowed" as you put it is relative to your intentions regarding intellectual property. [EDIT - Jan - Inappropriate]
Fortunately for those providers who use .out format scripting, Wellington won't "spill the beans" as there's no profit there for him.
As I said, you can get the know how via Google and Youtube. It's not one click and it's done, but if you want to, you can learn it.