Inserters moving stacks into nearly-full cargo wagons...

[Moosfet]

I decided try the one-inserter one-chest train unloading shown here:

https://www.factorio.com/blog/post/fff-140 -- look under the heading "circuit network examples"

It works fine, but it seems there's a rather obvious missing feature to go along with it, which is being able to do the reverse: Loading various different items into a cargo wagon using one inserter and one chest.

The problem is that, say there's a slot for repair packs that has 1 remaining, and you've researched some inserter stack bonuses, so your lamest inserter is going to pick up two items at a time. All will go well until it gets up to 49, then the inserter picks up two more repair packs, loads one into the cargo wagon, then stops with the other in its hand, despite there being plenty of other item types it could load into the cargo wagon. The same thing happens when loading items into the car's trunk.

I'd call this a bug, but it's really more of a missing feature: The inserter should be smart enough to know that it can only load one more item into the cargo wagon. It does, after all, know what types of items it can load, and it already looks at the quantity since it knows if it can load any items or if the slot is already full (in which case it decides to load a different item), it just fails to use that information to decide how many items to pick up and instead always picks up a full stack.

EDIT: ...or, well, repair packs stack to 100, but you get my point: It would get to 99, then stop with the extra repair pack in its hand.

[ssilk]

I think this is similar: viewtopic.php?f=5&t=27545 Train stations and circuit networks [0.13]

[Jupiter]

What you can do is create another inserter right next to your loading inserter that first takes any remaining items out and recycles them (perhaps feeds them back to your loading mechanism). Then you would have the loading inserter wait until the unloading inserter is done. To detect that it is done you can check whether it's hand is empty even though there is a wagon in front of it, which in turn you can detect using signals outputting their status.

[MindChanger]

Me and some people are creating train suppliers.
viewtopic.php?f=8&t=28268

U can take a look and if you like that then you can just use one of our systems!