Factorio Forums

Basics
Once you have researched the Electric Trains technology, you can start crafting a bunch of overhead line poles and a few electric locomotives. Then, it's time to power up your first railway. You can use any railway you've already built, normal trains can drive on the powered sections just fine.

Placing a pole is just like placing a rail signal. In fact, there are even poles that have integrated rail signals. However, for the standard poles that don't have a signal, it doesn't actually matter, on which side of the rail they are placed.

Poles can be placed up to 16 tiles apart, but in a curve a pole needs to be at most 3 tiles away from that curve. As it is currently (0.16) not possible to draw the wire whenever it can connect, there is a warning message instead if the poles are too far apart. This can be turned off in the mod settings if you find it too annoying.

When you placed down the poles and they connected successfully, you'll see green particles to inform you that the connection is established and the green rails are now powered. Conversely, if you remove a pole, red particles show you the change to the unpowered state. If you want to see, which rails are powered or unpowered after the fact, you can use the Overhead line debugger. Simply select an area with it, and all rails show their powered state. This can be especially useful when designing intersections.

Speaking of intersections, it can get pretty messy if you install a wire on every path the train can take; on some intersection designs it is even impossible. You can consider to only power a part of the rails though: When a train travels through the intersection, it usually has enough momentum to make it through without stopping. Or, if you want to be on the safe side, just add a locomotive in either direction on either side of the train.

If you want to have signal wires between your poles, you can just install them like you would on normal power poles. The mod also offers an option to automatically install circuit wires between newly placed adjacent poles.


Once you have built a network of powered rails, you can finally add your locomotive. Simply place it on the powered rail and you're done! Of course, only if your power poles are actually connected to your power network: You can easily do this with a vanilla power pole next to it. Now, your locomotive will never need to refuel and can simply drive on and on and on (As long as you don't have a blackout of course). You'll also find that the overhead lines have a power coverage area, just like normal power poles. This allows you to place entities like lamps or inserters next to the rail without needing additional powerpoles.

There are currently three tiers of locomotives with the following characteristics. (Acceleration is compared to a vanilla locomotive running on coal)

• Tier 1 (Electric Locomotive): Power usage 600kW, Top Speed 285 km/h, Acceleration 150%
• Tier 2 (Advanced Electric Locomotive): Power usage 1.2MW, Top Speed 311km/h, Acceleration 200%
• Tier 3 (Modular Locomotive): Power usage 1.8MW, Top Speed 311km/h, Acceleration 250%, upgradeable with modules

The modular locomotive is a special one: It has an equipment grid, which can take specialized modules to improve it's statistics. You can place up to four modules in the locomotive. An info text will pop up once you close the GUI to inform you of the new stats of the locomotive. There are multiple different setups you can try:

• Add three speed modules and an efficiency module for trains that need to go long ways and have a long time to reach maximum speed
• Add three productivity modules and an efficiency module for trains that need to start and stop often and need high acceleration
• Add two efficiency and two battery modules to get a locomotive that can drive a long time without the need to be under a powered rail
• Experiment yourself! There will be a setup just right for your needs.

Entities
A powerpole consists of multiple entities that work together. First, we have the placer entity. This is the thing that is placed by the item, but is never actually used ingame. It's use is mainly to allow it to be rotated in 8 directions and to get the UI for placing a rail signal (even though a standard pole isn't one). Once the placer is built, it is immediately deleted and replaced by the actual entities.
The first is the base, which is either a constant combinator for the standard pole, or a signal for the signal pole. The purpose of the base is mainly the signal behaviour for the poles that need it. It also doubles as the attachment point for the circuit wires.
The next entity is the power consumer, which is also visible in the power GUI. The entity itself is rendered as the vertical part of the pole.
The wire holder is separated from the pole, as it needs to be on a higher render layer: The holder is quite high, so it always needs to be rendered above trains. The issue is, that the Factorio API doesn't allow modders to freely choose a render layer of every entity, therefore the wire holder is an additional one. It doesn't serve any purpose other than visuals.
The final entity is the attachment point for the copper wire. It is a completely invisible medium power pole that is placed somewhere on the rail. (It actually has a small selection box in order to allow the player to change the wiring if something with the automatic placement goes wrong).

So, overall, a pole consists of a total of four entities.
You might wonder why I didn't just use a normal power pole type and be done with it. The issue with that was, that power poles rotate whenever they want to get the "best" wiring pattern. You cannot at all force them to stay in one direction, what I obviously need for the overhead lines. Therefore, the only power pole I used is completely invisible.

Powering the trains
It would be easy if a train could simply plug in to a power area and just... work. Unfortunately, trains are locked to a burner power source. Therefore, I somehow needed to refill the fuel tank all the time. I decided to do a refill every second to save UPS, but that is configurable too.
I created a dummy fuel item, which has as much energy as a locomotive is supposed to store. This item is set to be the fuel of the locomotive. Note that it isn't actually placed in the inventory, as the electric locomotive doesn't have one, it is just set as the "currently burning item". It is set only if the fuel has run empty, which might happen when the train loses power shortly.
The next step is to find out whether the train is actually below an overhead line. To make things easier, the mod keeps a cache of all rails that are powered (remember the green icon?) and maps them to the closest power consumer in a power pole. The locomotive to update then simply checks what track it is standing on, looks in the map and if it finds a power consumer, it knows it is powered. Then, the burner fuel is topped up from that pole and the next locomotive can be handled.
All of this is unfortunately quite complicated, but it somehow works quite well.

The modular locomotive
This one is even more hacked together than the other locomotives. First, I needed some kind of inventory for the modules. Luckily, you can give locomotives an equipment grid, so I used that. However, the equipment you put in there obviously cannot change the locomotive's base stats as these are defined in a read-only prototype when the game starts.
The only way to change the acceleration and speed of the locomotive is via fuel items. Therefore, I created a bunch of dummy fuel items that are swapped out whenever the module configuration is changed. This is also the reason for the hard cap to four modules: If I allowed more, the amount of dummy items would simply explode.
If you know your math, you can calculate that with four modules picked from five options (no module is also an option of course) without taking the order into account, there are already 70 different dummy fuel items. With only one module more, there would be 126 items needed, with two more even 210! I found it quite unreasonable to create that many (pretty much unused) items, which is why the module count is capped at 4.