Would I have permission to modify the mod? I was thinking of adding my own train variants for my world. I couldn't find anywhere else to put this, so I put it here

I would strongly suggest using the Resource Pack Creator item to add new trains, however you can fork the mod and add trains that way, only bear in mind that it's a lot of work to keep your own branch up to date with all the new features and other people may be hesitant to download the forks. If it's a train you can find irl in London, New York or Hong Kong it may well get added to the main mod.

Well, we are Getting a Train from León and Germany

Well, we are Getting a Train from León and Germany

Sorry forgot to put the rest of the comment lol, as I've already said, the trains are specific trains for my world and it's extremely unlikely that they will be added

Nevermind, I just realised it's open source, if there's any issues with making my own then just put them here and I'll delete it

You can do so by just making a resource pack; @jonafanho has a tutorial series on how to do this.

Yes, the video is here: https://www.youtube.com/watch?v=QH1O-y6kPSk&list=PLp0jZgheSlXv_vjilwnbrOtdbmgvz1VkC
The mod is licensed with the MIT license, which means you can look at the source code and existing models.

I would strongly suggest using the Resource Pack Creator item to add new trains, however you can fork the mod and add trains that way, only bear in mind that it's a lot of work to keep your own branch up to date with all the new features and other people may be hesitant to download the forks. If it's a train you can find irl in London, New York or Hong Kong it may well get added to the main mod.

Ok thanks, and I doubt it will be added officially as it's a train service for my world, with names from cities.