See title, and investigate other possible upgrade/recycling paths.

idea:

• use the kit system for all the 4 variants.
• when you want to replace a track, use the kit to replace the track. however there is a disadvantage that you will not get back the original track.
• Edit: the kits are easy to craft. same recipe as the other kits but with their variants.
• edit2: track replacer cart are allowed to use kits to replace the tracks.

The code is not easily co-opted for that, it would need to be a new item. Neptunepink suggested making Rails upgrade items, the problem is the cost disparity.

You could always up the amount of rails you get from the rails recipe.

You could try something like this and similar for normal -> electric and maybe
reinforced -> reinforced electric

I guess that works, not really compatible with the track relayer though.

@CovertJaguar I suggest making rails consumable like tools, each is good for 16 blocks of track. It should be able to upgrade both iron and hs track types.