[0.17.50] Mirrored fast inserters on express underground do not pick up

[RVice]

0.17.50

I created a blueprint that drops fast inserters on opposite sides of an express belt to insert into a steel furnace. I have multiple copies of the blueprint down with many of them working. I wonder if it is the inserters competing for a resource on the express underground. Ripping up the underground and putting it down again seems to allow the inserters to work again.

When I have a chance to get some more time in, I'll see if the problem comes back. Maybe inserters should not work on the express undergrounds (this would eliminate the space-saving blueprint I have).

[EnigmaticAussie]

Do they pickup at all?
Or do they "chase" the items on the belt?

[Rseding91]

Thanks for the report however I'm quite sure this is not a bug. Express underground belts have a very small window for an inserter to grab an item and if an inserter doesn't move to it in time it will miss the item. That's nothing new and has worked that way since forever.

Unless it's something other than that, this is just how it works because inserters chase items on belts.

[RVice]

I understand the "chase" but they are not moving at all and sitting on the underground belt. They do work when I first placed everything down.

Here's additional information that I recall from last night. There was a backup of ore to the input of the chain of steel burners. The ore goes to the last steel burner where it ends in an upward underground belt. Seeing the block where the ore meets the first underground near a power pole I wondered what was happening. Tearing up the underground belts and replacing them got the system running again.

In this case, the ore is "stopped". However, the inserters are not picking up from the underground belt.

Maybe the issue is with "stopped ore on an underground belt"?

[RVice]

Close this as not-a-bug. Found the problem, had construction robots on the belts. Doh.

Reason replacing the underground belts worked, it picked up all the construction bots on the belt. Solution, put a filter splitter prior to remove undesired inputs.