Balance Fluid Train Unloading Station

[Spaghettificator]

Hello!
I'm currently trying to figure out how to evenly discharge a 20 fluid car train carrying oil from really far away and then load them in small 1-2 fluid trains in the main base.
My problem is discharging them evenly. My OCD dosen't allow me to just unload them without being even on all cars!
So i was trying to follow this tutorial on reddit:

https://www.reddit.com/r/factorio/comme ... receiving/

But i'm having problems understanding what they are saying, eapecially the user talking about multiplying the number of tanks by the negative. I think he skips some steps along the way because no matter what i do, it doesen't seem to work properly.

Maybe some lf you guys have some idea how to do this?

Thank you for the help and stay safe!

[wobbycarly]

I'll try to help, but I can't easily add pics right now, so it might be a bit unclear. I've recently watched people play like this, and also started incorporating similar unload balancing to both liquids and solids.

A few assumptions I've made. 1) you have 1 pump from each wagon into 1 tank per wagon. 2) the train will sit at the station for as long as necessary, and you want to empty the tanks (not the wagons) evenly. 3) you also have pumps on the output side of the tanks.

If any of these assumptions are incorrect, you may need to tweak this a little. Eg, if you want to unload the wagons evenly, just change which pump is wired.

First, link up all the tanks with a red wire. Optionally attach it to a pole (so you can see the total) and then wire to the input of an arithmetic combinator. Set the combinator to input "each" and DIVIDE by the negative of the number of tanks. Output OIL. To see the result, hook the output of the combinator to a different pole with a red wire. If the tanks are full you should see -25k OIL on the red signal.

With the same red wire output, run this to each output pump of the tanks.

Now using a green wire, hook up each pump INDIVIDUALLY directly to the tank they are connected to. Again, assuming the tanks are full, each green wire will be outputting +25k OIL. So each pump gets -25k on the red wire and +25k on the green wire, net result 0.

Set the pumps to run when OIL >= 0. They will immediately start pumping and will keep pumping IF THEY ARE AT OR ABOVE the average value in all the tanks. eg, if you had 5 half-empty tanks when you started the wiring, the value on the red wire would be ((15*25k)+(5*12.5k)/-20 = -21.875k). The content of the tank is added (25k) to this value, resulting in 3.125k for the fuller tanks. Only these will pump until all tanks are at the average, and then they'll all start running again.

Hope this helps - have fun!

[Ranger_Aurelien]

If I really wanted to drain a train quickly What I would do without using logic network would be to have two (or three) pumps per car direct to a tank, then a pump direct to that tank pushing out to a second tank. That second tank then will have a pump to normal pipeworks to a really large communal linked storage tank solution. You then pump from that to your smaller outgoing trains in a similar multistep system. Try to minimise the amount of normal pipe as they have small fluid flow capacity.

so:
traintank > pump1 > tank1 > pump2>tank2>pump3>pipe[...]pipe>pump4>silosystem

The first tank1 is to try to keep empty and be able to drain the train in as short a time as possible. The second tank2 is to be a buffer to keep tank1 empty and then trickle it to the storage system through normal pipes. You then reverse the pump system at the other side so you keep buffers full to fill trains as quickly as possible...

But I acknowledge there is no "balancer" system to keep them even if the solution backs up, but as long as the mast holding tank is not full these buffers should move quickly.

Note fluid speed details:
https://wiki.factorio.com/Fluid_wagon

YMMV


(edit: added link)