Is your feature request related to a problem? Please describe.
Not really. However, it can be quite time consuming to add slightly modified versions of custom train models to the mod.

Describe the solution you'd like
I wish that templates can be added for the RP creator. How it works is basically when you open it, there should be a GUI with the names of the trains that are in the base mod. When you click on a train, the train would show on the resource pack creator and the player can edit the model based on the template that spawns.
For example, if you click an M-Train Small, the M-Train texture, model and its structure for the Small version is loaded and you can modify it to your liking.

Here is a mockup of how the template screen could look like.

This does not need to be high priority and thank you for the mod :)

looks nice

Could also be expanded to custom railway signs too.