Single side loading to underground belt

[Amarula]

When loading on to an underground belt facing the same direction as the inserter, the load is placed on the right side of the belt as expected.
However, when the underground belt is facing away from the inserter, the load is placed on the left.

I had hoped to be able to use an underground belt to unload from a train, using the inserters on one side of the train to load the right side of the belt, and the inserters on the other side of the train to load the left side, resulting in a fully loaded belt. Instead, both sides load the same side of the belt, requiring splitting and merging to load both sides of the belt. If you insert on to a regular belt feeding in to the underground belt, both sides are loaded as expected.

I don't see anything in the wiki documentation for belts or inserters that captures this behaviour, possibly related to the side blocking of the underground belt?

It would have made such a lovely compact train unloading setup...

Single side loading.png (1.05 MiB) Viewed 980 times

[PyroFire]

It only takes 2 stack inserters to get a fully compressed blue belt (one side).
I see you've got 6 inserters there across the 3 trains per belt lane.
Bit much?
Thought i should point that out.

Also this is normal and has nothing to do with whatever this "side blocking" thing you're talking about is.

[Pi-C]

When loading on to an underground belt facing the same direction as the inserter, the load is placed on the right side of the belt as expected.
However, when the underground belt is facing away from the inserter, the load is placed on the left.

I've asked about the same thing some time ago. Got some ideas how I could load both sides of a belt in the following postings.

I don't see anything in the wiki documentation for belts or inserters that captures this behaviour, possibly related to the side blocking of the underground belt?

It's here:

Inserters only place items onto one side of the belt, either the far side from the inserter's perspective or if the belt is going the same or the opposite direction as the inserter the right side from the belt's perspective.

It would have made such a lovely compact train unloading setup...

That's what I thought, too, at the time.