Train Waiting Yard

[paouk]

Hi there.

I'm new here in terms of account registration but i've been playing factorio since its release on steam.
I love the game, the devs, and all the comunity it has generated, One of the best ever for an indie videogame.
(from Italy so...sorry for eventually bad english)

In topic. I made a pseudo-symmetric smelting station. Every train (Input ores/Output plates) enter the station from middle south.
In my intentions here, the trains Input-ing Copper Ore would wait on the left side and the Iron trains on the right,
always leaving middle lane clear to trasint.

I can also accept the trains waitin on te sides regardless of the materials, but i need the middle lane to be used only for routing manouvers throught the different sections of the station.

The situation in the pic. instead, is all i can obtain every single idea i was able to try.

Can you gently suggest how to put signal/chains to obtain that result(if it's possible) ?

Thx

[blizgerg]

My understanding of train behavior is that the trains use a shortest path algorithm to find the shortest non blocked path. The path through the center is the shortest non blocked path. It is also the path that gets the train the closest to the station before it has to stop and wait. Though, I am unsure if the path that gets the train closest before having to wait matters to the pathing algorithm.

I wonder if there is a way to make the pathing algorithm consider a path as having a large penalty?

[searker]

The pathing algorithm gives more weight to a track if there is a station on it that is not used by the train meaning such a track would appear longer to the pathfinder than a track without said station.

Due to that, it might be enough to add a station in the middle and not use it in any schedule (i.e name it "Z_DontUse").
If that doesnt work, you´d have to add a station at the end of each stacker (thats what the "waiting yards" are mostly called) and add them to the schedules of the copper and iron train respectively. Since stations cant be placed on diagonals, you´d either have to change the outputs (left and right of the copper train in your picture) respectively or add a station to each lane in the stacker.

Another solution would be split the shared track between each stacker and smelter into a track which goes only from stacker to smelter and one that connects the current middle lane with everything but the smelter.

[Selvek]

I don't think putting a station on the middle track will work. Every train will path around it, and unless all the "waiting" tracks are full, the train will go through the shortest "waiting" track rather than the center track.

I have to ask, though, is there a real issue with how it exists right now? Sure, trains will wait in the center track, but them doing so will not block anything.

[searker]

I don't think putting a station on the middle track will work. Every train will path around it, and unless all the "waiting" tracks are full, the train will go through the shortest "waiting" track rather than the center track.

This is basically what OP wants. Obviously, any train that should only use the middle lane would have to stop there, but ore trains would ignore it.

The current issue as far as i can see it is the fact that the fork in the north does not only serve the smelters, but also other stuff. If 7 iron trains were to block every lane from the middle onward to the right, no train could get to any station that shares its input with the bit leading to iron smelting.

[paouk]

Thank you guys!

Another solution would be split the shared track between each stacker and smelter into a track which goes only from stacker to smelter and one that connects the current middle lane with everything but the smelter.

Thanks seaker for your suggestion. I honestly don't like the idea of putting fake stations to "trick" the pathing algorithm, it sounds like a "pork-around".
This one i quoted, instead, it's way more interesting. I think it could be possible to connect the middle track one step further of the ore station track.
I have to study this option a bit in relation with my production needs. Like you've already seen, this is the most trafficated section of my rail system and it's going to grow more.

The current issue as far as i can see it is the fact that the fork in the north does not only serve the smelters, but also other stuff. If 7 iron trains were to block every lane from the middle onward to the right, no train could get to any station that shares its input with the bit leading to iron smelting.

It is correct, but WOW.. 7 trains of input? I think they would saturate that smelters anyway.


Anyway, I thought the trains did what they could to reach the "nearest" blue chain signals, following the path until the very next signal block is unclear to proceed. Am i right ?


Thanks all again!
This game, simply can't get annoying XD

[paouk]

Also, I cant't understand this behavior:

The situation at the stations ahead is the same you could see in the first post, same test saved game, so the copper ore unloading station is busy but the waiting area is all clear.

I tried having only chain signals on the middle track in order to give logical priority to the signals before the stations. It result in this.

20170510001806_1.jpg (876.49 KiB) Viewed 9021 times

Looking at that situation i decided to put a direct signal on the entrance track, just ahead of the main line junction and before the 3way-fork.
I was expenting the train would have choosen right or left grenlit chain insteat of stopping that way.

20170510001826_1.jpg (808.41 KiB) Viewed 9021 times

Could you enlighten me about this? I can't figure out if it is the expected behavior, or if i just messing up something.
Why it choose the blue signal insteat of one of the greens?

Thx

Goodnight (here)

[orzelek]

I believe that pathing algorithm likes only shortest path. Longer paths are not taken into consideration even if they would take you closer to goal.
I would think that standing train penalty on middle rail should be enough to bump trains onto sidings but it seems it isn't. Or it's not being applied properly.

[Dojums]

i use an extra stop in my stacker, to prevent them taking the shortest routes...

Ore loader -> ore stacker - > ore unloader

this will prevent them taking the middle lane when stackers are empty

this will also allow you to keep them there, until a certain condition is met at the unloading station ( combinator stuffs )

if you need some help on it, i don't mind taking a look in your game, maybe help you sort some of your questions around the signals

you can contact me on steam: Dojumsz

[mrvn]

Try putting only chain signals on the middle track but normal signals on the waiting bays.

If that doesn't help here is something that will work for sure:

Put an extra stop "xyz (waiting yard)" each on every waiting bay and have the ore trains go to that station first with 0s of inactivity. Then ore trains will for sure enter a waiting bay and never use the middle track. The drawback is that they won't even use the shorter middle track when possible and will always stop in the waiting bay. Wastes a bit of time to break to a stop and accelerate again.

[paouk]

Thank you all guys!

Considering how many of you suggested the "stacker stop", i had to reconsider my opinion on that solution.

I actually ended up putting some "Copper Stack" stations on the left and "Iron Stack" stations on the right.
Then i set a stop on "passed time 0s" to all the trains that need to unload their ore at the smelters.

The result is impressively good!

Not only for aesthetic reasons, monitoring the yard in use for few minutes i noticed a very good improvement about the traffic (therfore in the throughtput) for the Output stations.

Now it works perfectly smooth, having input ore trains choosing their side at the entrance and decelerate to the waiting area, immediately leaving greenlit the middle transit lane.

Thanks again, i was loosing my mind in this rail section

[Dojums]

Now you see how it works, you can set circuit conditions coupled with the stations that it will only leave the stacker if station supply < X amount

and wire that to your stacker stops

[mrvn]

Now you see how it works, you can set circuit conditions coupled with the stations that it will only leave the stacker if station supply < X amount

and wire that to your stacker stops

Why ever would you do that? Simply set "inventory empty" as train stop condition and limit your buffer chests to X. Or enable the unloading inserters only if the amount in all buffer chests is < X. No point having all trains waiting at the stacker stop, one can wait at the unloading station itself.

That is unless you unload multiple goods at the same station. In that case you can allow only those trains to leave the stacker stops that can be fully unloaded and no train will block the unloading station because you have too much of one item and no enough of another. But having stacker stops in that kind of setup kind of defeats the purpose. (Fast) inserters and wooden chests are not that expensive and you might as well change the stacker stops to unloading stops.