Factorio – How to Train (Useful Tips)

Beginners Tips to Train / Rail

Trains are a topic which many new-ish players shy away from. They seem complex because what happens with them does not always have visible causes and we don’t get obvious visible results when we set them up like we do with belts and inserters. Still they only have a few basic rules they follow. Understanding those rules makes it possible to create some really strange, and quite useful, things with the rail network.

Unless you have a specific question about one place in your train setup a screenshot probably won’t make a difference. The game, in the Tip and Tricks section does have some mini tutorials to help learn about trains.

Perhaps knowing the rules trains follow, explicitly listed, will help. Or, at least get you far enough into trains to have specific problems which can be solved with help from others.

The basic, and absolute, rules which trains follow are:

• The locomotives only “drive” forward (they can be pulled backwards but then they are not part of the control of the train, just an extra heavy empty cargo wagon)
• The signals and train stops on the right-side of the in-control locomotive are the important ones
• Any train signals on the left side of the in-control locomotive act like “Wrong Way” signs for trains unless the is also one on the right side exactly opposite it.
• Train signals, either kind on either side, divide the tracks into “blocks”
• In automatic mode, no train will ever go into a block where there is already a train.

One special point about the “rules” is that they are ignored when the player is driving the train on manual mode. The system will detect a train in manual mode and change signal conditions when it is a block, but you can “run the red light” any time you want, and it is possible to manually drive a train into one which is in automatic mode.

Again, since I don’t know what parts you do, or do not, understand, I’ll just stick with the basics and word it as if you don’t understand any of it. What you already know can just be ignored.

Rail signals are what create the “map” of the rails as seen by the train control logic. Each signal “guards” the block after it. Rail signals, the regular ones with 3 lights, will be red if there is a train, any part of one including the last inch of a cargo wagon, anywhere in the block it guards. The signal will be green if the block is empty, and no other trains have reserved it already. All trains will stop at a red signal. All trains will continue on a green signal. The one train which has reserved the block will go on a yellow, all others will stop.

Rail chain signals, the ones with only 1 light. will follow the same rules, and trains will stop or go using the same colors. The difference is that chain signals will also check the next signal. If the normal rules would make the chain signal green, then it will copy the color of the next signal on the track. If the signal would be yellow under the normal rules, the chain signal can still turn red if the next signal is red.

Chain signals have a fourth color, blue, which is for cases when the signal could be green, or could be red (or yellow). The “block” after a any signal includes all the track, no matter how long or short, between the signal and any next signal. A block can include a split into 2, or more, directions, and each of those directions can have a signal. Empty of full for that block is the same rule as any block, one piece of any car on any track in the block means the block is not empty. Picking which signal is the next one depends on which way you want to go. If the chain signal would be green under the normal rules and there are more than one “next” signal then it will turn blue if at least one of the next signals is green and at least one is not. A blue signal means there is at least one way to continue, but not all paths are open, and the train has to look for the open path, and stop or go based on which path it wants to take.

There are a few things the game does to help make placing rails and stops easier. When you are holding a train stop in the cursor near a track, it will show where the train would stop, which way the train would be going. It also shows the next few wagons in the train. The settings menu will let you change how many “cars” will show here, and with signals, when the “train” is shown for you. If you are holding a rail signal, or chain signal, in the cursor near a rail it will show green squares any place that signal can be legally placed. It also will show a white square on the opposite side of existing signals to show where it could be placed to mark two-way rails. The game will also show all the existing blocks using colored lines. The colors mean nothing, and they can change often. The only “meaning” of the colors is to show where each block starts and stops, the same as using colors on a world map to show the different countries. The game will use as few colors as possible, which could be 2 colors repeated over and over. When placing a signal the game will also show which way the train would be going to read that signal and where the train would be if it had to stop there with white rectangles for the cars.

That’s all the “rules” there are in the game. Any other rules are ways people have decided to build the network. Some are basic, and avoid problems. One of those is the mantra of “chain in, rail out” which means to use chain signals at the start of, and any where inside, an intersection and rail signals at the exit from the intersection. That helps avoid deadlocks where two trains get stuck trying to move across each others paths. It is a good rule to follow, but explains nothing if you don’t already know how the signals work to begin with.

Perhaps, with this information, you can get far enough into building train systems that you can see mostly how they work and if you do have problems they will be specific and answers which help can be found.