TL;DR
Be able to read and make a signal of a vehicle/cargo inventoryWhat ?
For Car and Tank : when we plug a tile of belt under a vehicle, my suggestion is to have a third option after the belt reading, but instead of reading what is in the belt, the option allow to read the car or tank inventory on that tile of belt.For train cargo wagon : be able to plug a wire on a rail section, this signal will read the cargo inventory like a belt do, but for the cargo only, not for the whole train.
or if those options are not possible, a item like this mod allow to have : https://mods.factorio.com/mod/Inventory%20Sensor add in the classic game
Why ?
I know that my suggestion can be achieve with a mod, but we are here to give consistency to the basic game. When I'm trying to push into a full vanilla build, sometimes i can't achieve with the vanilla tools what i'm trying to do(mostly car on belts automation part), or with too many intermediate (so useless complexity) compare to the starting idea which is simple.This suggestion give a true tool to deal with a problem i got about saturation (production control) of an item and a easy way to make my trains departure condition if just one cargo is empty (not easy to make "balancing" with train/car on belt transition)
This request is also slightly related to this thread viewtopic.php?f=6&t=71855 with the big idea to have useful tools in the logic network to deal with car on belts and the "item flow".
