[Idea] Read individual cargo wagon contents

[UnseenFactory]

You can read the contents of the full train via the train stop, but what if you can read the contents of an individual cargo wagon?
This might help with making balanced train (un)loaders. I barely use circuit networks, but if people like the idea I can try and make mod out of it.

You can't connect wires to a train directly (which makes sense), but what if you can connect a wire to train track and it will output a signal when there is a wagon it?
Because there can be 2 wagons on one track you should be able to connect 2 wires as well.

Any other ideas or suggestions about this are welcome.

[disentius]

would this help?
https://mods.factorio.com/mod/Inventory%20Sensor

[UnseenFactory]

Oh haha, it already exists.
Probably way better made than I would be able to
Thanks! I'll go check it out.