From Novice to Journeyman by /u/grays42

Transcription

1 Factorio Train Automation From Novice to Journeyman by /u/grays42

2 Introduction Welcome to the Factorio Train Automation tutorials! This series is separated into three parts: Novice, Apprentice, and Journeyman. Each part will help you understand more complex workings of a functioning rail network in Factorio. Before we get started, please make sure you are viewing in a slideshow format. Many of the demonstrations will not flow smoothly if you are scrolling with a mouse. For PDF readers, make sure you choose single page or fit to page view. If you are viewing on imgur, make sure you put /all at the end of the album address and choose Fullscreen at the right.

3 Part 1: Novice Stations, Signals, and Blocks Let s begin with Part 1! Before we dive into automation, you should first learn to run a train manually. Lay some track down, put down an engine, and move around. You ll need to fuel it with this symbol: Enter gets in/out, W-A-S-D moves and turns. W is always forward from where the train faces. Set up the intersection to the right and move around on it to see how trains can navigate merges and crossovers. Once you re comfortable, let s automate a train!

4 Part 1: Novice Stations, Signals, and Blocks To automate a train, first place a station along the track in front of the train (can t go backwards). Notice the arrows? That s because stations can only be approached from one direction. Give your station a name by clicking on it. Next, click the train and use the train scheduler to add the station with! (You can delete it with ). will begin automation and will revert to manual operation. ( picks a specific station if you have a long list of them.) Press to automate your train!

5 Part 1: Novice Stations, Signals, and Blocks And away it goes! Easy, right? So what happened here? The train actually did two things: 1. It first had to find a path to the station by tracing a line through all areas it is explicitly allowed to go. (It will display No path if it can t find a route.) 2. It then began to move to the station, stopping for any areas occupied by other trains. In this case, it encountered no other traffic and just went to its station. It will stay there for a number of seconds set by the train scheduler. So how does a complex train system meet these two objectives?

6 Part 1: Novice Stations, Signals, and Blocks Enter: the signal! When you place one, you ll notice it s one-way, like the station. This is the first function of the signal: explicitly allows the train to use the track in that direction. Trains will never go through signals that don t point the correct direction. Trains that can t find a correct signal will not be able to find a path! A signal on each side of one spot allows trains to travel in either direction along the track:

7 Part 1: Novice Stations, Signals, and Blocks The second function of a signal is to prevent collisions by breaking up groups of track into sections called blocks. A block is any number of tracks crossing, merging, or splitting that is bounded by signals. If the block in front of the signal is not obstructed, the signal turns green. If there s something blocking the track, the signal is red.

8 Part 1: Novice Stations, Signals, and Blocks Here, you can see the blocks identified as boxes. Red boxes are obstructed and green boxes are available to be entered by trains. Even though this second train isn t even on the path to the station, it s still in the third block. This prevents collisions!

9 Part 1: Novice Stations, Signals, and Blocks Also, remember that our signals are one-way. If we put signals in the other direction, the lights on those will show occupied blocks in that direction.

10 Part 1: Novice Stations, Signals, and Blocks Creating and managing blocks are the basic function of signals and a fundamental aspect of all rail networks.

11 Part 1: Novice Stations, Signals, and Blocks So what happens if we automate that train? I want to get to that station.

12 Part 1: Novice Stations, Signals, and Blocks Trains in Factorio will always move to the last available block on the path they have chosen. In this case, it will move to the end of the second block and stop until that block is clear. The next block is occupied.

13 Part 1: Novice Stations, Signals, and Blocks Also, trains will always select the shortest route given multiple options.

14 Part 1: Novice Stations, Signals, and Blocks If that route becomes obstructed somewhere, it will calculate a new path, as long as it has an option to change to a different block somewhere down the line.

15 Part 1: Novice Stations, Signals, and Blocks But what happens if its final block is obstructed?

16 Part 1: Novice Stations, Signals, and Blocks The train will choose its best path and wait at the final block for the obstruction to clear.

17 Part 1: Novice Stations, Signals, and Blocks Last example: We have two trains going in opposite directions, and a third line cuts across both. They should be able to safely cross at the same time.

18 Part 1: Novice Stations, Signals, and Blocks However, the center is all one block. If one train enters, the second has to wait.

19 Part 1: Novice Stations, Signals, and Blocks Any time you want to allow for multiple trains to pass, you can separate sections of track into their own blocks with more signals. Like this. it s a trap!

20 Part 1: Novice Stations, Signals, and Blocks * Both can pass through at once. Everyone s happy! *Actually, we have now exacerbated a huge problem. More on that next. This concludes Part 1: Novice! (ignore that guy, he s fine.)

21 Welcome to Part 2 on your path from Novice to Journeyman! In this section, we will discuss intersections and chain signals. In Part 1 we covered the basic components of a simple rail network: stations, signals, and blocks. Using these, you should be able to get trains from point A to point B fairly easily...assuming nothing else is moving in the network. When you involve two, four, or twenty moving trains, things get considerably more complicated. But we will come prepared! Let s begin with the intersection we fixed at the end of Part 1.

22 An intersection is defined as any group of crossings and merges where a train can encounter a train from a different line. We set this up in Part 1, but we have a problem that we didn t notice.

23 We re in the same situation as before, with our train wanting to get to the station.

24 This time, though, the train can t get to its station. There s another train there--it could be out of fuel, loading ore, or just waiting.

25 Our train doesn t know that. It sees a green signal and pulls out into the intersection.

26 Now our train, who could have waited before the crossing, is blocking the intersection...and another train is coming.

27 So our northbound train is now also stuck, and the problem just keeps getting worse as another train approaches.

28 So now our problem with just one line is a problem for three, when those other two could have been moving freely even with one stuck situation. This kind of issue can quickly spiral into a deadlock, where every train is blocked by at least one other train. It all started when our first train entered the intersection and couldn t exit.

29 From this example, we can come up with a rule we can enforce for all trains so that they never encounter a situation with a blocked intersection:

30 From this example, we can come up with a rule we can enforce for all trains so that they never encounter a situation with a blocked intersection: Golden Rule Trains must never enter intersections that they can t completely exit.

31 From this example, we can come up with a rule we can enforce for all trains so that they never encounter a situation with a blocked intersection: Golden Rule Trains must never enter intersections that they can t completely exit. The Golden Rule of intersections? Great! So...how do we enforce that?

32 Enter: the chain signal!

33 Enter: the chain signal! Chain signals have all of the existing functions of regular signals.

34 Enter: the chain signal! They make blocks and check for obstructions just like regular signals.

35 Enter: the chain signal! However, they also look ahead to the next signal and turn red if it s obstructed!

36 Now let s go back and re-signal our intersection. Our intersection encompasses every encounter between different lines. Remember the Golden Rule! The train must only proceed if its exit block is clear. Can I exit this intersection?

37 We want to make decisions based on the exit blocks to the intersections, so we put regular signals on those. The behavior of those signals determines what everyone approaching the intersection is looking at.

38 Now we want to address the incoming traffic and tell them to watch what happens to the exit block so they know whether it s safe to enter the intersection at all. We do this with chain signals before every crossing. Nope! That chain signal is red. My exit isn t clear.

39 Great! Now our intersection is completely safe to use without deadlocks. The blockage cleared up and the train is ready to move forward into our completely safe intersection. Except...what if another train is passing?

40 We re back to our original problem that the intersection is one big block! The first time, we solved this by placing a signal in the middle, but that caused a deadlock. Fortunately, we now have a much better option.

41 By placing a chain signal, not a regular signal, in the center of the intersection, we have safely split the eastbound and westbound lines so traffic can flow freely without causing deadlocks!

42 Notice what happened here, though: This isn t really a clear block! The upper block being occupied is telling the northbound line that it is not safe to enter, but allowing traffic through the eastbound line. This incredibly powerful behavior is what enables huge intersections to be safely used by many trains at once.

43 From this we can deduce several Principles used to enforce the Golden Rule.

44 From this we can deduce several Principles used to enforce the Golden Rule. 1. Signals before the exit blocks of the intersection. As previously discussed, the exit block is the only thing that a train heading to an intersection should be concerned about.

45 From this we can deduce several Principles used to enforce the Golden Rule. 1. Signals before the exit blocks of the intersection. 2. Chain signals every other time a line crosses or merges with another line. An intersection only begins when one line encounters another. At the moment this occurs, until reaching the exit block signals, every encounter must have a chain signal. We never want the train to be able to enter the intersection without taking into consideration what is happening at its exit block.

46 From this we can deduce several Principles used to enforce the Golden Rule. 1. Signals before the exit blocks of the intersection. 2. Chain signals every other time a line crosses or merges with another line. 3.??? There s a third intersection principle, but it s actually outside the intersection, so we ll cover it in Part 3 when we start having intersections interacting with one another. Hint: it enforces the last part of the Golden Rule that requires you to completely exit the intersection.

47 There is one unusual exception to these Intersection Principles: merges at the exit block of an intersection. In both of these examples, three trains need to merge into one exit block. In the top example, we ve put regular signals exiting the intersection, whereas in the bottom, we ve used chain signals.

48 What we ve done on top is turned the entire merge into one giant exit block. For the bottom, we have three chained blocks.

49 However, when any one of the three enters the exit block, both configurations perform exactly the same way. This is because these three lines share a single output. So for the case of exit merges only, the merges can be combined into one large exit block. (Note: This is a shortcut! Either option will function just fine.)

50 We have one last thing to discuss about chain signals before we move on. A train approaches a chain signal we will place here before the lane splits. What color will it be? Hints: A chain signal will act like a signal and be green if its block isn t occupied. A chain signal turns red if its block, or the block following it, is occupied. However, one exit block is green, one is red. So which will the chain signal be?

51 Neither. It turns blue! What does that tell the train? I need to see my next block, is it clear? Um...maybe? It depends on which way you re going. You figure it out!

52 In Factorio, a moving train already knows the path it wants. A blue chain signal tells the train to check the next block in its individual path, because chain signals are global, not per-train. The chain signal itself has no idea which path the train wants to take, it just knows that some exits are obstructed and some aren t.

53 Next, we re going to create a one-way spur coming off of a block in an existing double-track network. (Don t worry about the double-track bit For now we ll discuss network types in Part 3.)

54 First, we need to figure out where we will put our connecting rails; we only need two, because there are only two ways to get to the new line. These need room for signals. (This will require some trial and error.)

55 Now, we need to identify: Where is the intersection? The only place the intersection actually exists is the group of crossings and merges where one train can encounter a train from a different line. We have one of each. Splits are not part of the intersection because there is no chance for one train to encounter an occupied block until the next signal down the line.

56 As we discussed before, we can consider this merge at the exit to be one big exit block. Again, this is an optional step. Chain signals will also work exactly the same way, it will just make the exit block further down the line.

57 (Enforcing Principle #1) Now we need signals on the exit blocks. One of them is already provided because we re modifying an existing block. We could actually back this up to just after the crossing if desired. It actually does give us more room in the larger network, so let s go ahead and do that.

58 (Enforcing Principle #1) Now we signal the northern exit block.

59 (Enforcing Principle #2) Finally, every time an interior rail encounters a different line, it needs a chain signal. In this case, there s one other encounter in the intersection, so we need a chain signal for each line leading to it.

60 And we re done! That was easy, right? Let s try it out. Here come two trains.

61 The westbound train arrived first, so the chain signal sees an obstruction and stops our northbound train.

62 Our train sees that its chain signal is green, indicating that all the blocks through to the exit block are unoccupied. It begins to move into the intersection.

63 The train crosses into the intersection, and now occupies two blocks. This means we haven t yet cleared the lower, eastbound line. In a real situation, this signal leading to the exit block would turn red, because our northbound train has reserved its path through the intersection so it doesn t get stuck.

64 Now that we ve cleared the bottom block, the lower line becomes available for other traffic.

65 As we move into the exit block, we still occupy the last bit of our intersection, so we can t clear the westbound lane yet.

66 We ve cleared the intersection! We have now restored traffic through the eastbound and westbound lanes. Note the chain in the center, though; it s informing any new northbound trains that it can t use the intersection yet. Side note: As a rule of thumb, it is generally preferable to place your exit signals as close to the intersection as possible, so that exiting trains clear mainline traffic faster. We did not do so in every case for this example so that the signaling demonstration is easier to understand.

67 Here s a complete summary of the process we use to signal an intersection: 1. Identify the intersection. This is the group of encounters (merges and crossings) where two trains from different lines can meet. a. Splits don t count because there s no way for two different lines to meet. b. Merges at the exit only may be treated as one exit block because the lines all the way through the intersection share one output. 2. Place signals before the exit blocks for each line exiting the intersection. 3. Place chain signals on each line leading to an encounter. And that s it! Using those steps, based on the Principles, which enforce the Golden Rule, you can correctly signal any intersection. Remember that we re missing one Principle; we ll learn about it in Part 3, when intersections interact.

68 Let s do one more example before we finish. Let s signal a T-junction for a double-track network. This may look more complicated, but we can easily signal it using our same steps.

69 First, we identify the intersection. This is the group of encounters where trains from two different lines can meet.

70 Three of these encounters are merges at the exits, which we can consider parts of the exit blocks. We will not need chain signals here.

71 Now we identify and signal our exit blocks. (Smaller for clarity, but normally you d want to push these back)

72 Finally, we chain signal all other encounters between different lines. (Sometimes the positioning can be tricky because you can t place a signal in the middle of a curved piece of track.)

73 And that s it! We re done! You now know where to place signals in any intersection. This concludes Part 2! You can now put intersections anywhere you want to in your network! it s a tr yes, I said that on purpose, because we're discussing that in Part 3. Go away.

74 Part 3: Journeyman Rail Systems and Networks Welcome back to the final part of our series! In Part 1 of this series, you learned the basic concepts of stations, signals, and blocks. In Part 2, you learned how to build intersections and use chain signals. So far, everything we have done has been in a vacuum; we haven t made a rail network and have had no discussion of how these pieces interact. Now we need to tackle problems on a larger scale. Let s get started!

75 Part 3: Journeyman Rail Systems and Networks Almost everything we ve made so far has been one-way. Let s discuss why. Suppose I want to connect these two sections of my network that are some significant distance apart. (far apart)

76 Part 3: Journeyman Rail Systems and Networks We could use our intersection we made in Part 2, but it will only allow for travel in one direction. What if we want two-way travel?

77 Part 3: Journeyman Rail Systems and Networks We can certainly build it! We just follow our intersection steps. But, watch what happens when a train uses it.

78 Part 3: Journeyman Rail Systems and Networks The instant that the train enters the exit block, the entire line becomes obstructed. The other train has to wait on the mainline! No amount of signaling can prevent this. The entire line is one giant block.

79 Part 3: Journeyman Rail Systems and Networks Have you ever stopped at a construction light that turns a two-way road into a one-way road? That s what a two-way rail is like, except all the time. So, never let two-way rails merge with your network at more than one intersection. (Two-way rails are fine for spurs and stations.)

80 Part 3: Journeyman Rail Systems and Networks Instead, every mainline (general transit line) in your network needs to be at least two one-way lines. This is called a double-track network.

81 Part 3: Journeyman Rail Systems and Networks It is also important to distinguish between two types of double-track networks: left-hand drive (LHD) and right-hand drive (RHD). There are no significant advantages or disadvantages for either, but the signaling for all intersections is completely inverted, so it is important to be consistent with whichever orientation you pick for your network. Left-Hand Drive (LHD) Right-Hand Drive (RHD)

82 Part 3: Journeyman Rail Systems and Networks Next, let s make a station in our network! We re going to use a standard one-way intersection to get to a station off of a RHD double-track, just like we did back in Part 2. This time, though, it can t exit; trains can only move forward.

83 Part 3: Journeyman Rail Systems and Networks In order to get back onto the mainline, we have to choose a rail system. The two rail systems available to choose from are: The terminal system* The loop system There are advantages and disadvantages to both systems. *The terminal system is often mis-stated as double-header, which means trains with two front engines.

84 Part 3: Journeyman Rail Systems and Networks The terminal system involves trains with engines at both ends (actually called top-and-tail trains, but we ll just call them terminal trains). Stations and spurs for this system are on two-directional lanes and need a two-way intersection to get back on the mainline.

85 Part 3: Journeyman Rail Systems and Networks Terminal system implementations are more compact than loop system implementations and involve fewer blueprints, so most Factorio players tend to prefer them. On the other hand, terminal trains accelerate more slowly due to the added weight, requiring more engines for larger trains, which involves larger blocks and larger stations. (Also, they re ugly.*) * 2-headed trains have no style or soul. There, I said it. -Zisteau

86 Part 3: Journeyman Rail Systems and Networks Loop system implementations require extra rails to allow the train to turn around. They occupy considerably more real and require more estate consideration for For these reasons, loops pathing/deadlock tend not to be as popular issues. as terminal systems for general-purpose use.

87 Part 3: Journeyman Rail Systems and Networks Loop stations can also be implemented with a second one-way intersection, but this causes real estate problems as well. In the end, the choice is Also keep in mind that terminal yours, and since both work trains can use loop stations, but on a double-track network, loop trains (one engine) can t back you can use either for your out of terminal stations. more specialized stations.

88 Part 3: Journeyman Rail Systems and Networks Now let s talk block size. Small blocks are usually fine, but in some cases can cause problems. We re going to use this loop station as an example, but this can happen on any intersection if not managed properly. We have an obstruction: There s a train out of fuel on the eastbound mainline.

89 Part 3: Journeyman Rail Systems and Networks The train gets ready to get back onto the mainline, and its signal is green because its exit block is clear.

90 Part 3: Journeyman Rail Systems and Networks However, it s too big to fit into the exit block, and now the tail of the train is sticking into the intersection. This is a big problem because another train is coming.

91 Part 3: Journeyman Rail Systems and Networks So what was once a problem for just the eastbound line is now also a problem for the westbound line, which otherwise would have been able to pass through.

92 Part 3: Journeyman Rail Systems and Networks To fix this situation, we have to make our exit block bigger. If the entire train fits, it will prevent the westbound lane from being blocked*. Naturally, moving around all of this track is very annoying, so it would be better for this not to happen in the first place. *as long as this station is only used by one train. (See links in the epilogue.)

93 Part 3: Journeyman Rail Systems and Networks Well, good news! This just happens to be our final Intersection Principle! 1. Signals before the exit blocks of the intersection. 2. Chain signals every other time a line crosses or merges with another line. 3.???

94 Part 3: Journeyman Rail Systems and Networks Well, good news! This just happens to be our final Intersection Principle! 1. Signals before the exit blocks of the intersection. 2. Chain signals every other time a line crosses or merges with another line. 3. Each exit block must be at least as long as the longest train that will use it.

95 Part 3: Journeyman Rail Systems and Networks 1. Signals before the exit blocks of the intersection. 2. Chain signals every other time a line crosses or merges with another line. 3. Each exit block must be at least as long as the longest train that will use it. Following these Intersection Principles for the Golden Rule will make your rail network almost* immune to deadlocks, as long as you have enough blocks.

96 Epilogue So what s next? Well, now you know how to build deadlock-resistant* rail networks to connect all of your outlying outposts up to your main production hub. There are going to be congestion concerns as your network gets bigger, but there s a lot of subjectivity to how to handle those, which is outside the scope of our tutorial. There are all kinds of community resources, but now you have the tools to understand those pictures of giant intersections and how they work. So congratulations on making it this far. You are now a Journeyman rail network designer! Now, only practice and patience will make you a Master.

97 External Links *It is important to note that high congestion and multiple trains using some stations can still cause deadlocks. For more details, see Antaios guide to Stations, Junctions, and all things deadlock on the official forums. As as your network grows, you will need to learn techniques to manage congestion. There are also a few mods that enhance the rail design and management experience that you might be interested in: The Fat Controller is incredibly useful for remotely managing your trains. Fully Automated Rail Layer (FARL) will place rail and blueprints while you drive, making rail-laying in the late game much faster. Resource Spawner Overhaul (RSO) spaces out ore patches and places rich ore patches much further from the initial spawn, making rails necessary.

98 Credits Special thanks to the redditors of /r/factorio who contributed advice, corrections, and suggestions in discussion threads while I was building the tutorial series: /u/ak47_killstreak /u/artorp /u/chummchumm /u/freetambo /u/michael_lewandowski /u/qulqu /u/calbrenar /u/cosmicosmo4 /u/ichthyos /u/redditnamesareshort /u/teammisha /u/dartonrejen /u/kann_ /u/michaelthe /u/chocki305 /u/maxcreeger /u/nihilrexgaming /u/rootnegative /u/uffefl /u/para_lu /u/strangepostinghabits /u/w3y And of course, thanks to the developers of Factorio for making a fantastic game!

99 Goodbye! /u/grays42