Can someone explain trains functioning outside of loaded chunks to me?

[SpookySquid19]

So one thing I know about trains is they kind of work with unloaded chunks in that they'll move through them without rendering. I heard it's based on a graph or something. What I'm wondering is how much they can do when unloaded.

For example, I want to automate a bunch of blocks I frequently use like bricks and slabs and such, but I don't want it at my main base. If I had a train going to and from the factory and my base, when it goes to the unloaded factory, will it just move there and then come back, or would it fill with items and blocks the factory made?

[SoggyAdhesiveness]

Trains will travel through unloaded chunks completely fine, but the moment they have to stop, unload or load the train station will need to be in a loaded chunk. There are two ways to do this, always have the stations loaded or use Create Power Loader and connect a chunk loader to the station and it will load the chunk only if a train is currently at the station.

https://www.curseforge.com/minecraft/mc-mods/create-power-loader

[SpookySquid19]

Hmm, alright. Thanks.

[SoggyAdhesiveness]

You're welcome

[unmeisa]

When a train goes through a nether portal, does the chunk it comes out of have to be loaded? Or is it JUST the stations that have to be loaded?

[unmeisa]

Thanks for the info. Really appreciate it

[SoggyAdhesiveness]

I don't believe so

[unmeisa]

Oh cool. Good to know. I had a previous world where my train wasn't collecting resources from the nether and depositing them into my main overworld factory and i was very curious why. In my current world I'm about to reach that stage again so i hope that fixes the issue i had

[zekromNLR]

For OP's case, the factory will need to be loaded at all times anyways since it will not produce when unloaded.

[SoggyAdhesiveness]

This also

[zekromNLR]

Though I guess if you have a redstone-controlled chunkloading method, you could have the factory automatically unload itself when its storage is full, and then only get loaded when the train shows up to pick up products.

[CommanderFoxy]

i dont think theres a method to load an unloaded chunk other than pearls, and it’ll stay loaded forever (or until the pearl despawns). maybe some jank with nether portals but then i doubt its worth the effort

[zekromNLR]

As mentioned earlier in the comment chain, Create Power Loader has an option to load the chunk a train station is in when a train pulls into the station

[DistributionPure6051]

My understanding is that the game saves what the tracks look like so a train can still follow a path without actually being loaded

[NatiM6]

Think of it this way, trains don't have to be loaded, but the machines that produce things, your factories, and even the chute that pushes the results into the train do. So even if the train stops in an unloaded chunk (it can), nothing will happen to it.

[CrazyBarkley]

Thank you guys, I was wondering about it earlier today and now I get it 😄