would u make an optifine version that would make the models appear after you rename a furnace minecart as a red train, blue train or yellow train

also make a green train, vanilla minecarts will be still on place but furnace minecarts renamed will have the custom model.

maybe you could even add some train cars, like a passenger car for a regular minecart and a boxcar for a chest minecart and they can be obtained by renaming too

But you should add compat for the On a Rail datapack because when i use that command the locomotive appears simply as an floating furnace