You're absolute right but what are the useful categories? There is no committment between the modder and normally they defines mostly one with their own name. Do you think about the categories "Raw Material", "intermediate Goods", ""Manufactured Goods" and "Finished Goods" as he described them on transportfever.net?

The mod itself is awesome but all those mods requires a new game.

how could this be done? Ill check the mod documentation again this week as I haven't read it in around 2 years to see if I can find the solution