high capacity unloading station

[Nexarius]

This unloading station is capable of full compression 24 blue belts balanced output.
It's too big even on max zoomed out view for a complete screenshot because it has a waiting area for 20 trains.

blueprint

Seriously?! The blueprint string is too long

https://pastebin.com/raw/6HGmQpBX

[mrvn]

Lately, and since underground belts are longer, I've been wondering about the need for waiting bays.

Why have trains sitting in waiting bays? They could be unloading. You have 6 double sided unloading stations and 20 waiting bays. Now if you got to to 12 single sided unloading stations you still have the same throughput. What if you go to 24 unloading stations? If at least half of them have trains in them then at all times then you don't need the buffer chests. That means you only need 3m separation between tracks (well, 4m since 3m isn't possible), which is the separation your waiting bays have. So basically convert all your waiting bays into unloading stations.

To save resources you could also unload half the station to the left and half to the right. Use underground belts in the middle, then fast underground belts and express underground belts on the outside.

[evildogbot100]

Waiting bay are much thinner than actual station, also for a station that thin, the throughput is severely limited. Also without waiting bay, you rarely able to make a station has near 100% uptime (duration it is loading/unloading). Since the throughput of a station also depends on its uptime, it is a waste to not fully saturate a station usually. Thus the waiting bay.

[DaveMcW]

The main purpose of waiting bays is protection from traffic jams. You can have 5 trains sharing an unload station, and normally only 1 is there at a time (the others are travelling or loading). But if all 5 trains arrive at once, you need somewhere to put them.

[Nexarius]

How do you want to make 24 stations with no waiting area and have at least half of them with a train at all times? That can only work if the travelling distance of the trains is so short that it's almost useless anyway.

When I used this station in my world the waiting bays were empty most of the time but still necessary because if the ore is filled up the trains will come to the station and need a place to wait otherwise it will a very long traffic jam.

[mrvn]

Waiting bay are much thinner than actual station, also for a station that thin, the throughput is severely limited. Also without waiting bay, you rarely able to make a station has near 100% uptime (duration it is loading/unloading). Since the throughput of a station also depends on its uptime, it is a waste to not fully saturate a station usually. Thus the waiting bay.

Except they aren't. Not with one waiting bay every 6m like in this setup. The idea also isn't to have all unloading bays 100% saturated but to have enough trains in enough unloading stations to saturate the belt.

Think about it this way. The trains are always the same speed, take the same time to get to a mine, load ore and return. But time spend in a waiting bay is time wasted. Now you unload the train directly. Even though unloading will be slower, because no buffer chests are used, I think overall that probably evens out.

[Nexarius]

Unloading would be slower -> time wasted

Why should we do that?

[mrvn]

The main purpose of waiting bays is protection from traffic jams. You can have 5 trains sharing an unload station, and normally only 1 is there at a time (the others are travelling or loading). But if all 5 trains arrive at once, you need somewhere to put them.

Yes, you need to be able to handle all trains being stuck at the unloading station. That's why I suggested changing the waiting bays to unloading stations and not suggested to remove them. The number of trains that can fit in the station at the same time wouldn't change.

As for there only being 1 train at the station: That depends on the time it takes to unload and the number of trains you can fill with ore. Unloading 1 train into 12 buffer chests per train car takes something around 6 seconds with maxed out stack inserters. Unloading onto 6 belts take significantly longer. Add to that that you have more trains unloading than the belt can take and the ore will back up. Trains will be unloading much slower in my setup. This gives the ore mines more time to fill their buffer chests though. So less time spend waiting for the train to fill at that end.

But from my experience what you want is to have trains arrive faster than the belt can take away ore. Because if you don't produce enough ore then no amount of buffer chests or train efficiency will prevent the smelters running out of ore. You want trains backing up. You want the waiting stations to be always filled to some degree. When you reach that point the buffer chests will overflow and the unloading of trains will slow down to the belt speed. So if that is the goal then why have buffer chests at all? I think buffer chests only help when you don't have enough trains because the extra loading/unloading speed lets you get away with less trains.

[quote="Nexarius]
Unloading would be slower -> time wasted

Why should we do that?
[/quote]

Ideally the ore/s unloaded remain the same. But now it would be unloaded from more trains in parallel. The time for each train would go up, true. But the time trains are stuck in the waiting bay would be saved. And the time spend moving between the waiting bay and the unloading bay is eliminated.

So on the negative side:
- trains spend more time unloading
- more train stops
- no buffer chests

On the the positive side:
- trains don't waste time in a waiting bay
- trains don't spend time moving between waiting bay and unloading station
- less inserter per train station
- no buffer chests

One other advantage of this idea. With all trains having an unloading station you can disable stations at mines until they have enough ore buffered to fill a train. Hopefully there always is a mine with enough ore buffered at all times and the next empty train would drive straight to the nearest ready mine. And if not then that is a clear sign more mines are needed. You could set up an alarm to tell you when more mines are needed (e.g. empty train waiting for more than a minute or more than 5 empty trains waiting).

[Xtrafresh]

The reason to have separate waiting bays and unloading stations is to make sure the trains are unloaded one by one. In your 24-station unloading grid, you'll end up with 24 trains, all with a handfull of stuff, waiting to be unloaded. The trains that get to unload first at the earliest point on the belt) will empty out quick, and all the other stations will just be filled up with trains that can't unload. In essence, your 24-station area will effectively be an non-buffered 6-station unloading grid, plus an 18-bay marvel of stagnant wasted resources, trains and space.

Back to OP: Nice design, 24 belts, whoa!

[schaf]

Hi,
I just build this massive Bahnhof and have question.
On wich trainstation do i send the train, or it dosen't matter on wich I will send the train and the circuit choose a free trainstation?

Thanks for this work!

greetings schaf

[Nexarius]

You should give all stations the same name thats all

The circuit is just there to force the trains to use both the 3 right stations and the 3 left stations and not just have all trains go to the left most station all the time. (red lamp = disabled station)

[schaf]

Great @Nexarius, work like a charm!

One little thing, There are requesterchests on the station, should they put a request when the output on end of the belts are low, b/c the requst chest put no request on.

greetings schaf

[Nexarius]

They will request whatever is on the output belts. I added them to remove any excess ore that is in the logistic system (only useful when you don't use bot based smelting systems).

[p4nda]

hi
you have same thing for high capaticy loading?