Trains - supply-push, or demand-pull?

[AileTheAlien]

Couldn't find any threads with this, so hopefully this isn't covered somewhere else...

Is it generally easier (or more efficient? or faster? or...?) to have trains based on supplying the needs of each manufactuing zone, or to have each train supplying one material to multiple zones?
i.e.
- One train for iron plates, going to several manufacturing zones / train stops, one train with green circuits ...?
or
- One train carrying all the ingredients for making green circuits pulling from multiple supply areas, one train pulling all the ingredients for blue science from multiple supply areas...?

My hunch is that the first option is easier to keep track of, and have fewer trains, since every train just has a new stop added to its route, for every zone that needs that material. The second option seems like it would have a tonne of trains, but they could all be shorter, and could stay parked at their drop-off destination to keep the congestion down on the train network. Maybe my intuition is wrong, and they're equally valid / efficient / etc.

Thoughts?

[Kelderek]

I prefer simplicity whenever possible and trains are a good example. There's no best way to do it, it's all a matter of preference. Any issues of congestion will depend on your layout and how well you planned the flow.

In my games, all my trains have a single cargo type with a few exceptions. An example of a multipurpose train for me is my defense supplier: a small train that delivers items needed at my defensive positions (walls, turrets, construction bots, ammo, etc.). I usually like to use the main bus method for belting resources in a local area. If I set up a separate manufacturing area, then I also set up a separate bus too and use trains to deliver the most basic ingredients. I have been playing for years and have yet to use trains to move things like green or red circuits, but I have tons of trains for ore, smelted plates, coal, stone, uranium, oil, acid, etc.

As your volumes increase then you would benefit from transporting intermediate items instead of just raw materials. You can cut down metal trains by half if you smelt your ore on site near your mining drills before loading it onto trains.

[iceman_1212]

The question of "how to design a train system" is secondary to the question of "how to design a factory". As you'll see from the many different styles of factories that people post, there are varying opinions on what's the most efficient. The metric that is most important is throughput, i.e., are you able to get your stuff to where it needs to be. In my experience, train networks are rarely the throughput limited step for most factories.

The way you're thinking about it is right imo - after you decide how to structure production for your current base, you'll know how to set up trains.

I have experimented with a couple different setups:

(1) train network used only for hauling ore and oil to main base (i used this style for my starter science bases in 0.14),

(2) one train network for hauling ore to central smelter followed by a separate train network for distributing plates, intermediates and final products (i.e., separate subfactory for greens/reds/blues/RCUs/etc),

(3) smelting + production of key intermediates on site (i.e., at the mine) followed by distribution to subfactories.

(Note: #2 and #3 were set up in the late game.)

I'd encourage you to play around with different factory structures as well as different train/train station configurations (RORO vs. terminus, top-and-tail vs. trains with all locomotives facing one direction, etc.).

[Frightning]

Couldn't find any threads with this, so hopefully this isn't covered somewhere else...

Is it generally easier (or more efficient? or faster? or...?) to have trains based on supplying the needs of each manufactuing zone, or to have each train supplying one material to multiple zones?
i.e.
- One train for iron plates, going to several manufacturing zones / train stops, one train with green circuits ...?
or
- One train carrying all the ingredients for making green circuits pulling from multiple supply areas, one train pulling all the ingredients for blue science from multiple supply areas...?

My hunch is that the first option is easier to keep track of, and have fewer trains, since every train just has a new stop added to its route, for every zone that needs that material. The second option seems like it would have a tonne of trains, but they could all be shorter, and could stay parked at their drop-off destination to keep the congestion down on the train network. Maybe my intuition is wrong, and they're equally valid / efficient / etc.

Thoughts?

demand-pull is better imo because it avoids the potential issue of one process starving another. You can also customize the train length and other parameters to accommodate different usage levels (e.g. probably only need 1-1-0 for something like Transport belts, but you will probably want more than a 1-1-0 for Steel plate for instance).

[Aeternus]

I prefer both push and pull for different purposes.
Mines deactivate their station until a cargo is available. My mines are labeled with the same station name so trains will service any mine of the same type. I still need to make a system that prevents more trains going out in search of resources then there are active stations available - but I got some ideas on how to do that.
Anything else gets a push - shoving more resources and half fabricates into a midsized buffer until the whole thing is saturated. Once the buffers start to drain I know production isn't keeping up, and I can expand/tweak whatever is not doing enough. It's not exact science that way, but a buffered approach can handle interruptions in the system and/or brief resource shortages.

[SpeedDaemon]

For production zones/sub-factories, I almost always "pull." Since 0.13, I don't even use buffers most of the time, but just have the train wait until something runs out, then circulate to the the output stations of other zones to refill. If necessary, I'll have more than one train, so by the time one needs a refill, there's a full one waiting behind it to pull in. Just set the wagon filters so that things all run out about the same time. This way, if that zone isn't working, the trains all fill up and pull in to the siding, which reduces unnecessary traffic.

(Disclaimer: I usually play with Bob's Mods, so a given production zone may have to import as many as 20 different raw materials. Having that many different trains try to get in to "push" supply would be a mess)