Satisfactory – In And Around The Lake

“… mountains come out of the sky and they stand there!”

Yes, ha ha, the song “Roundabout” by Yes (ha ha) earworms me every time I think about building roundabouts in Satisfactory. Maybe you, dear reader, are young enough not to have this problem. I envy you your youth and your lack of Jon Anderson’s voice in your head.

Anyway.

It’s been a wee bit since my previous train-related Satisfactory post and in that time I’ve given myself plenty of roundabout-making practice. I can confidently refute part of the advice I gave previously about “not crossing the streams tracks,” as long as you pay attention to the following general workflow. (Fear not, I’ll go into detail later on.)

• Stick with a two-lane track network, as discussed in the previous post. Trains should always only ever be heading one way along a given length of track. (Reminder: Right-hand drive is ideal due to how signals hang off the right-hand side of the track.)
• You’ll want a 9-by-9 foundation square around which to build your roundabout. It can be extended in either direction (or both) as needed, but the technique will take some adjustment if you do. (More on that, shortly.)
• For each direction from which you want trains coming in and for each direction to which you want trains exiting, add some foundations at that corner.
• Place unconnected lengths of track at the midpoints on each side. For a 9-length side, go from the middle of foundation #4 to the middle of foundation #6. (This is what you adjust if you extend a side.) What this gives you is something for your inside curves and your entry/exit runs to snap to.
• Connect your “middle bits” with curved tracks to complete the “round” part of your roundabout.
• Extend from the appropriate “middle bit” junction out to your exit/entry path.
• Place signals! There should be a Path Signal at every entryway, a Block Signal at every exit route, and absolutely zero signals inside the roundabout itself.

Believe it or not, that’s all there is to it other than hooking up your entries and exits to the rest of your network. You can use this to make a two, three, or four direction roundabout. (Why bother with a two-direction roundabout? So you can provide loopbacks for trains that re-enter the network from a station facing the wrong direction initially to get to their next destination.) Heck, one of the roundabouts I built this afternoon is a two-point-five direction setup. (There’s an extra “in” from my Aluminum Ingots factory.)

But you’d like some pictures, I wager. And I’m happy to provide them. First up, the basic 9×9 square. Note that I’m building this as a bespoke example setup so it’s not actually connected to my rail network, which is why you will see error indicators on the Block Signals later on.

Boring, but essential. Next, the extra bits for entrance/exit rail routing.

We don’t need to use all four directions, but I place them as a matter of habit unless I know for certain I won’t want them later. Now, for the sake of the YouTube this example build I’m going to highlight the “middle” foundation along one of the sides, like so:

Sadly, you can’t just snap from center to center to center and make a big circle. I mean, you can try, but you won’t be able to use those junction points to enter and exit the roundabout. There’s a limit to how many rail segments can snap together at one point. So it’s best to simply avoid that potential headache. Now, for a 9×9 square you’ll start at the middle of the foundation tile just off to each side of this center tile. If you’re expanding into a larger square/rectangle, what you need to know is to start your middle rail section 2.5 tiles away from the corner (not including the corner piece itself) and end it 2.5 tiles away from the other corner, as illustrated:

The reason for the 9×9 minimum is due to the minimum length of a rail segment, which is just about 2 foundation tiles’ worth.

Make four of these, one for each side, and you’re well on your way to a roundabout.

Now, connect each segment with curvy tracks.

The loopy part of the roundabout is complete!

Now for the entrances and exits. Run straight segments out from the appropriate nearest junction points from the middle rail sections on each side where you want traffic going in/out of the loop. Note that you want to leave a junction point near the roundabout itself. Or to put it another way, run these straight segments to points just outside of the original square.

Why?

You don’t want these “inside” the loop or it won’t work, but if you make the nearest junctions too far away you’ll increase the wait times for trains queued up to enter the roundabout. As soon as a path is cleared a train will be allowed in. Placing the exit Block Signal as close as you reasonably can will increase your transit flow. (Of course, if two queued trains are going to exit in the same direction one after the other, the second train won’t be allowed into the roundabout until the first has made it past the next Block Signal down the line after exiting. As noted in the previous trains post, if you think you have enough Block Signals, maybe you don’t…)

The same applies for the inbound Path Signal placement as well. The further away your waiting inbound train is from the actual roundabout, the longer it’ll take to get through the system.

This is, of course, when you can choose how many directions you want now versus later. In this case I figured three directions was plenty enough to get the point across. The foundations for the 4th direction remain in case I want to expand the network in that direction later, hypothetically.

(In reality I’d delete all the foundations and place pillars underneath for the aesthetic, which is why I couldn’t make this post with an existing roundabout: All the foundation tiles are gone!)

I didn’t want to place signals at the ends of tracks, so I extended things a bit to give myself something to work with. In your mind’s eye, picture these going to/from the actual live rail network.

It’s time for signals! At the junction points just outside the “main square,” place one Path Signal along each inbound track and one Block Signal along each outbound track. Note which side of the track the signal ends up on; you want it on the right side from the approaching train’s point of view.

Lather, rinse, repeat until all your entrances and exits are signaled. Note that as you place signals, the game will try to show you where the borders between blocks are by highlighting each block in different colors.

Say what now, you ask?

Not that you need to understand all of this in order to make a working roundabout, but it helps to understand why you do not want to place any signals within the “main square”: The game considers each section of connected rail, regardless of how many individual pieces of track make up that section and so long as everything is “touching” (so this includes merges and splits and criss-crosses) as a “block” when divided by Signals. What a Path Signal does is reserve a route through a given (complicated) “block” to prevent collisions.

The Path Signal doesn’t perform this “reservation” action until a train has moved onto the “block” leading up to that signal. So, a trick for making sure you don’t risk simultaneous reservations (which shouldn’t happen anymore, but why take the chance?) is to make sure the placement of each Block Signal “before” each Path Signal for trains nearing the roundabout is a slightly different distance further back. That way a train with a long “block” before the Path Signal will get its reservation “first” versus another train that only had a short stretch of track in which to make the reservation for its Path Signal.

It’s complicated, yeah. You’ll get the idea once you watch the trains doing their thing in your shiny new roundabout. Which, by the way, is all done! Enjoy watching your trains trundle back and forth and round and around! Heaven knows I lose plenty of time doing so after I finish one of these.

Are there other ways to do complex intersections? Oh goodness yes. This is merely one way to do one particular function that is very useful to how I play the game. Your mileage may vary, and you should (once you get comfortable with the concepts after some practice) play around with things and see what else you can come up with.

Now, if you’ll excuse me, I need to get that old Yes song out of my head…