Hello JATMN and firstly, you did an amazing job with Yuoki industries. I do have a request however as it seems you have nice control over LUA and might find a annoying bug
It is the Uranian train in Youki Railways... let me check the name of it: UP-Engine-Header. It takes 50 fuels but it does not use them and stops out in nowhere, claiming it has no fuel, but still when I check it, it has 50 uranian fuel cells. I exchange them now for steam engines instead but I do wanna use them for quick runs still... :/

UP-Engine-Header

Looks like this is related to the fact that Yuoki's Uranium train does not actually have an output slot for used fuel cells.

Ill need to check if this actually an issue in vanilla as well or if a 3rd party mod is forcing that this is an issue.

Looking at recipes.. I think the most practical thing would be to make Uranium Trains use Nuclear Fuel cells vs the current Uranium Fuel cells.. they dont have a required waste production.. though I am not sure that all mods have Nuclear Fuel cells..

Should be fixed now in 0.2.23
Still uses Uranium fuel cells.. but now it gives back the used-up fuel cells as expected.