Factorio Forums

In the attached screenshot the inserter wants to grab a coal from the exit tile of the underground belt. This setup *usually* works. It works with a long handed inserter in the same position. It works on the entrance tile of the underground belt. It works as pictured when the items on the belt are moving. It only ever fails, that I can reproduce, for a normal inserter with a north-facing underground conveyor exit with items stalled on it.

PS: In many other situations an inserter will start animating but fail to grab an item from the underground entrance, because the item disappears before the inserter can grab it. Those first few frames of animation do play in the situation of this bug report, but only occasionally, not consistently.

Not sure, if this is a bug. Because you need to use a fast inserter here. And if you are low on power even fast inserters can't grep things from normal belts. It's also documents (more or less)
https://forums.factorio.com/wiki/inde ... ound_belts

I think this is a very special detail in the belt physics, which is needed to know, when making very special setups. The difference between advanced and expert.

I believe it is a bug, and I have noticed some little problems with this as well, sometimes I need to add one more belt to the last exit of coal for this setup to work.
And it doesn't always depend on the speed, it might get stuck when the items are not moving anymore.
I will try to find some solution ...

Fixed for 0.9.1, the collision boxes are now set in a way, that it is also possible to insert into the underground belts.