Trains

Trains move large quantities of material over long distances, which belts cannot do efficiently. They arrive around the purple-science era and scale the late game.

Trains solve a problem belts cannot: moving large quantities of material over long distances. A belt is fine for feeding a smelter column a few tiles away, but stretch that belt across the map to a distant ore patch and it becomes slow, expensive, and a maintenance headache. A train hauls far more, far faster, between fixed stations. Trains become important around the purple-science era, since rails are a Production (purple) science ingredient, and they are the backbone of any factory that outgrows its starting patches. The 2.0 update added elevated rails for free, which makes routing across a sprawling base much cleaner.

How a rail network runs

You lay rails between stations and give each station a name, then set a train a schedule that routes it between those names: load at one, unload at another, wait for a condition, repeat. Naming is the key idea, because many stations can share a name, and the network sends a train to whichever one is available. That is what lets a single fleet of trains serve a growing number of identical ore outposts without rerouting anything by hand.

Stations, signals, and scheduling

A train schedule is a list of stops with wait conditions: leave when full, leave when empty, leave after a timer, leave when a circuit condition holds. Combine that with the circuit network and stations can be enabled or disabled by signal, so a train only travels to a station that actually needs material. That single trick, disabling an outpost station until its buffer runs low, is what keeps a large network from filling with trains running empty back and forth.

The combination of named stations and circuit-controlled enabling is what makes a train network scale. Trains go only where material is needed, and you add outposts without redesigning the schedule.

Where trains fit in a run

Trains arrive naturally with purple science, because rails sit in that pack’s recipe, and that timing lines up with when your factory starts reaching for ore patches too far away to belt. Early on, belts and the main bus are enough. The moment you are belting ore across a long, awkward distance, that is the signal to lay rail instead. From there, trains carry the heavy bulk flows, ore and plates, while belts and bots handle the short-range distribution inside each build.

Watch out for

Laying track before you need it. Trains are a mid-game tool, not a starting one, and a rail network you cannot yet feed is wasted effort.
Skipping signals and scheduling discipline. An unsignaled network deadlocks the moment two trains contest the same junction.
Running trains to stations that do not need material. Without circuit-controlled station enabling, a big network clogs with empty round trips.