Oil transporting tips!

[MisterSpock]

This is how i transport oil from my outpost to the base: (no mods)

1) The loading system at outpost


Here you can see im reserving half slots for the empty barrel and the rest for the filled barrel. Intelligent inserter make sure that only the right barrel is moved.





2) The unloading system at base


In close look you can see im using the requester chest to request 100 empty barrels. The problem is that empty barrels can block the system, if the chest is full. So i have a yellow inserter on my assembler with an active provider chest, to counter the overflow. Im sure logistic system would be better, but i was to lazy.





3) The system can support 2-3 trains. For more a buffer is needed. Like this:

[ratchetfreak]

so closed system at the outposts but an open one (under and overflow of empty barrels is accounted for) at the base.

[MisterSpock]

so closed system at the outposts but an open one (under and overflow of empty barrels is accounted for) at the base.

exactly!^^

[Gus_Smedstad]

I'm assuming you're deliberately avoiding belts because of lag / frame rate issues. And that you must have a mega-mega base, because generally speaking, even one level-3 assembler unloading oil barrels produces oil at a tremendous rate. Personally, I've never had a need for more than 1 train hauling two cars, one for empty barrels and one for full ones.

The issues I've had to address in transporting oil by rail were all about the empty barrels:

1) A source of new, empty barrels when the system needs them.
2) Limits on oil outposts so they don't take more empty barrels than they need - this is a non-issue when they're producing a lot of oil, but becomes important when a station has only depleted wells and produces only a few barrels between train visits.
3) An assembler unloading oil barrels will stop if there's no place to put the empties, and so a full output buffer can bring the system to a halt.

(3) means it's a good idea to limit (1) to producing what's actually needed, rather than just flooding the system with empties. (3) also rears its head if you were once pushing a lot of oil through the system, and thus had a lot of full barrels, but production slacks off enough so that what were full barrels now become empties waiting to be used.

Generally I've had a system where there's an assembler making empty barrels, and a smart inserter poised to put barrels into one of the output boxes only if the box is almost empty. The blue requester chests you're using have the same function though usually I'd have the limit at 4, not 100. I suspect the difference is that you're relying on logistic bots, which can be slow an irregular, so you need a bigger buffer. If there's a belt system moving new empty barrels from the assembler to the output, 4 is usually plenty.

For (2), I like to set up smart inserters linked to the local oil storage tank. If the outpost doesn't have at least 100 units of oil waiting to fill barrels, it doesn't unload empties off the train.

(3) has sometimes been an issue for me. An active provider chest is a reasonable solution, though I'd probably set it up differently. For example, I might set it up to take out of the output box with a smart inserter linked to that box, so it only takes barrels out if there are 400+ barrels waiting.

[nobodx]

On 2:
Can't you just use combinators to calculate the amount of (empty) barrels needed at the outpost ?

[MisterSpock]

On 2:
Can't you just use combinators to calculate the amount of (empty) barrels needed at the outpost ?

im not sure, keep in mint that this station is used by multiple trains and outposts.

btw: even with 4 outpost there is no problem with this system.

[ThaPear]

I'd like to take a look but postimg doesn't work at all for me. Could you upload them to another host (for example imgur)?
Postimg gives 504 Gateway Time-out on each image

[Gus_Smedstad]

On 2:
Can't you just use combinators to calculate the amount of (empty) barrels needed at the outpost ?

There are a few issues. Combinators can only see things in chests, so you'd have to avoid belts. Spock's oil outpost doesn't use belts, but I usually do, and it's much simpler moving train output to an assembler for loading if you use belts. Often, the calculation is irrelevant - the result is going to be either "nothing" or "all the barrels you can unload before the train departs," depending on whether the oil wells are still producing at normal rates.

The important thing is mostly to deal with the case where the answer is "nothing."

[katyal]

At work so I can't check but I believe you can hook up storage tanks to combinators

[ratchetfreak]

indeed and you can guestimate how much is on the belt (there is only so much room on the thing)

[Wolfwaffe]

Uh, i just use assembly machines on both ends, unload empty and full barrels straight into them.

[Gus_Smedstad]

Uh, i just use assembly machines on both ends, unload empty and full barrels straight into them.

That's fairly inefficient for a variety of reasons.

It limits train loading and unloading significantly. You can't load / unload any faster than the assembler can process, and you lose most or all of the container-to-container transfer bonus. Oil flow becomes highly irregular as it only moves when the train is in the station. Your only way of adding barrels to the system in an automated way is to load directly on to the train, which means you can't detect when more empties is a bad idea. Your oil unloading can come to a screeching halt if the car for empties fills up, since the assembler won't unload if it can't get rid of empties.

Even a single box as a buffer fixes most of those problems, though it means you're loading / unloading at about 1/7th the speed that's possible.

[voyta]

Even a single box as a buffer fixes most of those problems, though it means you're loading / unloading at about 1/7th the speed that's possible.

And where on earth you need 7 inserters worth of barrel moving? One rocket per second factory?

Edit: You could utilize it "slightly" sooner:
7 inserters * 10 items moved per second using inserter bonus * 25 oil per barrel = 1750 oil/s
1 rocket defense per minute factory (http://imgur.com/a/xcYxk) needed 425 oil/s (however that still used pipes rather than clunky barrels)
So that's about four "rockets" per minute. Of course rocket launch uses different amount of oil than rocket defense but it won't be order of magnitude difference, is my guess, and I'm too lazy to count that now.

Edit2: rocket+satellite seems to need 51200 oil "fractions" which translate roughly to 50k crude, which means 7 inserters can keep the pace of 2 rockets per minute. Again crude (pun intended) estimate, not searching for optimal cracking rates, not counting productivity modules, etc.

Side note, having rockets twice as oil hungry as rocket defense is kind of sad, because expanding the oil production is the least automatable of the mass-scale production tasks in Factorio, due to rigid placement restrictions on pump jacks.

[Gus_Smedstad]

It's true that oil cargo volume is much, much smaller than iron or copper ore. The "only one inserter" comment was a bit of a knee-jerk response, though I stand by the big difference between a basic, single-box buffer and direct loading.

You could theoretically need high oil volume if you're one of those people who insists on steam power all the time, no solar panels. They exist, though I'd never do that myself.