Several trainstations & empty barrels

[One33Seven]

Hi,

In my factory I have one huge oil processing plant with 20 refineries and lots of chemical plants, responsible for all my plastic and sulfur production. This plant is of course very oil hungry and so I also have several oil outposts which pump up crude oil and put them into barrels ready to be shipped to the plant via train. At the plant the full barrels are offloaded and the empty barrels are loaded into the same wagon.

Because the oil flow at these outposts isn't the same what tends to happen is that all the empty barrels get stacked up at the outpost with the lowest oil flow clogging the whole system. The empty barrels can't be unloaded so the wagons don't have any space for the full barrels and thus no full barrels are loaded and everything stops. Because of this none of the other outposts get any empty barrels and thus the whole oil flow stops.

So an obvious solution is to put more empty barrels in the system but this only shifts the problem to another outpost. Over time the outpost with the lowest oil production gets the most barrels and the outpost with the highest gets almost no barrels.

I'm looking for a smart way to distribute empty barrels over all these outposts.

/EDIT:

To clearify, I have one platform at the plant where all the trains stop. I have 3 trains running to 7 outposts. 1 going north, another going south/east and another going south/west. Each train stops at 2 outposts except the one going north which stops at 3 outposts. The wagons are used both for empty and full barrels. There are no separate wagons for empty and full.

[flyco]

Why don't you use smart inserters/intelligent chests to unload the empty barrels from the train and use a circuit network condition on the inserters so they will only work if there are less than, say, 1000 empty barrels in the chests?

[Neotix]

Long ago (before combinators and mods with tank wagons) I used tanks on outposts to store Crude Oil and smart inserters to unload empty barrels only when in that tanks was enough oil to fill all of them. In that way when train arrive and in tanks was enough oil, all barrels was filled. When outpost didn't have oil, then train pass by.
Also in base i unloaded full barrels only when in tanks was enough space.

[One33Seven]

Why don't you use smart inserters/intelligent chests to unload the empty barrels from the train and use a circuit network condition on the inserters so they will only work if there are less than, say, 1000 empty barrels in the chests?

Hi,

Thank you for the suggestion. I have thought about that before but the problem is that I do not know which train is at the station platform that moment. I have one train platform which is shared by all the trains

[ratchetfreak]

at the outpost have the smart inserter only pull out empty barrels when there are less than X in the buffer chest.

In the wagons reserve some slots for full barrels.

[twepy]

A very simple but effective way of collecting oil is using dedicated cars for either full or empty barrels. At the main base you load wagon 1 with empty barrels and wagon 2 stays empty, then at oil stop 1 a inserter unload empty barrels from wagon 1 and a second inserter loads the filled barrels on wagon 2 and repeat this on every stop. Back at the main base you unload the wagon 2 and restock wagon 1, the chance of this stalling is very slim.

The only thing left is limiting the amount of barrels unloaded at each stop, this can be done with a circuitnetwork and a smart inserter or limiting the amount of slots of empty barrel chest.

[terror_gnom]

when you click on a slot of a cargo wagon with the middle mouse Button, you can set a filter. Only "filtered" Item may be insertet in that slot. So you can divide your cargo wagons 50/50 with empty and full barrels.

To prevent deadlocks on the transport belt at the outpost, I´m running my belt in a 8-like shape, so that the empty barrels are at ne near side of the factory and it is always able to unload full barrels to the far side of the belt.